GUIDELINES for the HUMANE SLAUGHTER of ANIMALS General Introduction in 1963, the AVMA Convened the First Panel on Euthanasia

Home , Animal slaughter, Casting (fishing), Dead on arrival, Priest (tool)

1 GUIDELINES FOR THE HUMANE SLAUGHTER OF ANIMALS

2 General Introduction

3 In 1963, the AVMA convened the first Panel on Euthanasia (POE) to provide

4 guidance to veterinarians who perform or oversee the euthanasia of animals. In 2011, the

5 AVMA POE determined that there was a need to address and evaluate the methods and

6 agents that veterinarians may encounter during end of life issues for animals that fall

7 outside of euthanasia. The Guidelines contained with this document relate to Humane

8 Slaughter. The Panel on Humane Slaughter (POHS) Guidelines represent the first

9 iteration of its kind for AVMA in the area of humane slaughter of food animals. Content

10 of the Guidelines reflect AVMA’s on-going concern for both the ethical consideration

11 and the treatment of animals at the end of life. In the case of humane slaughter, the

12 POHS is dedicated to ensuring that no unnecessary pain or distress is inflicted on

13 conscious food animals prior to, during or after slaughter procedures. The POHS

14 Guidelines are part of a triumvirate -- the other two parts being the AVMA’s 2013 POE

15 (AVMA, 2013) and 2014 Panel on Depopulation (POD) (in Press).

16 The treatment of animals is increasingly becoming a subject for public debate and

17 discussions, especially in light of growing concerns about industrial forms of agri- and

18 aqua-culture, and food safety. The public and the scientific community are also

19 increasingly interested by the possibility of significant cognitive, emotional,

20 psychological, and social abilities in other species. Commensurate with waxing attention

21 on how their meat is raised, processed and prepared, the public has shown greater interest

22 in whether and how sentient animals are treated and the extent to which respect towards

23 animals are reflected in different human-animal situations. Elevated concern exists about

24 the environments in which food animals are raised and maintained, the quality of their

25 lives (including how animals are handled and managed), and the ways in which they are

26 terminated. The latter half of the 20th century and the first two decades of the 21st have

27 seen the proliferation of the scientific study of animal welfare to meet public concerns

28 regarding the ethical treatment of, especially, animals raised and slaughtered for food and

29 those used in biomedical research (Fraser, 2008). Attention to questions about the moral

30 status of animals has meant that veterinarians and others have had to demonstrate to the

31 public due diligence in their professional roles. Approximately 10-15% of veterinarians

32 are involved in promoting the health and welfare of animals that will eventually become

33 food (AVMA, 2008).

34 The POHS has endeavored to identify and apply the best research and empirical

35 information available to the humane slaughter of the different species of animals

36 considered in this document. To date, mechanical/physical, electrical and controlled

37 atmosphere/gas methods are employed to bring about physical disruption, hypoxia, or

38 neuronal depression in animals meant for slaughter. Social discussions regarding the

39 ethical care of animals will influence future recommendations. The AVMA encourages

40 its members to employ scientific knowledge and expertise to protect and promote animal

41 health and welfare in the service of animals and the public at large.

42 These Guidelines do not debate the use of animals nor do they delve into the

43 morality of killing animals for food or fiber. The POHS’ focus is on what should happen

44 to animals when slaughter is their ultimate fate. When animals are designated for

45 slaughter, they should be treated with respect and handled appropriately, and the

46 slaughter process should limit the harms experienced by these animals. Humane

47 slaughter methods and agents bring about the rapid loss of consciousness and the

48 complete loss of brain function in an animal designated primarily for the food system.

49 This means minimizing (and where possible eliminating) distress, pain, and anxiety

50 associated with the process of terminating the lives of the following species of animals:

51 hoof-stock (cattle, bison, horses/mules, sheep, goats, swine, deer, elk); poultry (chickens,

52 turkey, pheasants, ratites, geese, ducks); fish and rabbits. The ‘process of termination’ ,

53 as defined here, encompasses the period from which a farmed animal designated for

54 human food consumption is off-loaded at a slaughter facility until it is verified to be

55 unconscious and ultimately dead and ready for the food chain.

56 While the POHS is motivated by both the ethics and the science of animal

57 welfare, members of the Panel are also sensitive to adjacent concerns and dimensions

58 related to the humane slaughter of animals. These considerations include public health

59 and safety, food safety and quality, environmental and economic sustainability,

60 production adequacy and sustainability, occupational health and impact on the labor

61 force, international animal welfare and trade standards, and religious and cultural aspects.

62 That said, this document is not primarily concerned with meat quality or food safety. The

63 primary responsibility of doing what is in the animal’s best interest under the

64 circumstances (i.e., using the most appropriate and painless slaughter method possible,

65 and considering the context of animal welfare in the United States), should not be

66 outweighed by meat quality or economic arguments.

67 In addition, these Guidelines do not address methods and techniques involved in the

68 termination of animals hunted for food (subsistence or otherwise) or animals raised for their

69 fur or hide. The Guidelines for euthanasia should be consulted if individual animals are

70 deemed inappropriate for the food chain. The Guideline for depopulation should be

71 consulted in the event that zoonotic disease, foreign animal diseases, or other diseases of

72 concern to population health is suspected.

73 Historical Context, Membership of the Panel and Notes on the Current

74 The 2012 POHS Guidelines includes a wide breadth and depth of expertise in the

75 affected species and environments in which humane slaughter is performed. These

76 Guidelines span over a year’s worth of deliberation by more than 15 individuals, including

77 veterinarians, animal scientists, and an animal ethicist. Members of the Panel received

78 invaluable input from AVMA members and others during a designated comment period.

79 The scientific integrity and the practical utility of these Guidelines are a direct result of

80 member input and suggestions from others concerned about animal welfare of food animals

81 and the slaughter context.

82 In these 2012 Guidelines, humane slaughter methods, techniques, and agents are

83 discussed. Illustrations, diagrams, tables, and related graphics have been included to assist

84 veterinarians in applying professional judgment. Species-specific information provide

85 detailed guidance for terrestrial and aquatic species that are farmed and slaughtered for food.

86 While some slaughter methods may be utilized in euthanasia and depopulation,

87 recommendations related to euthanasia and depopulation are addressed by either the POE

88 or POD Guidelines. The POHS Guidelines specify appropriate slaughter methods and

89 agents, and are intended to assist veterinarians in their exercise of professional judgment.

90 The POHS Guidelines acknowledge that the slaughter of food animals is a process

91 involving more than just what occurs to an animal at its death. Apart from delineating

92 appropriate methods and agents, these Guidelines also recognize the importance of

93 considering and applying appropriate pre-slaughter and animal handling practices. Thus,

94 these Guidelines offer information regarding the handling of animals before and during

95 humane slaughter because veterinary responsibilities associated with slaughter are not

96 limited to just the moment or procedure of killing an animal. Information about

97 confirmation of death has also been included.

98 Statement of Use

99 The POHS has designed these Guidelines for use by members of the veterinary

100 profession who carry out or oversee the humane slaughter of hoofstock, poultry, rabbits and

101 fish. The POHS’s objective in creating the Guidelines is to provide guidance for veterinarians

102 about how to prevent potential pain and distress of animals that have been designated for

103 slaughter in accordance with the Humane Methods of Livestock Slaughter Act (HMSA).

104 As stated above, these Guidelines do not address methods and techniques

105 involved in the termination of animals hunted for food (subsistence or otherwise) or

106 animals raised primarily for their fur or fiber.

107 Veterinarians experienced in the species of interest should be consulted when

108 choosing a method of humane slaughter, particularly when the HMSA does not currently

109 cover the species being used such as with poultry and fish. In order to limit potential

110 harm to animals and personnel involved in the slaughter process, slaughter methods and

111 agents should be selected with a view towards maintaining a calm animal. Species

112 specific anatomy, physiology, natural history, husbandry and behavior, may assist in

113 understanding how various methods and agents may impact an animal during the

114 slaughter process.

115 Veterinarians performing or overseeing humane slaughter should assess the

116 potential for species-specific distress secondary to physical discomfort, abnormal social

117 settings, novel physical surroundings, pheromones or odors from previously slaughtered

118 animals, the presence of humans, and other factors. Other considerations include human

119 safety, availability of trained personnel, potential infectious disease concerns,

120 conservation or other animal population objectives, regulatory oversight, availability of

121 proper equipment and facilities, options for carcass disposal, and the potential secondary

122 toxicity. Human safety is of utmost importance, and appropriate safety equipment,

123 protocols, and expertise must be available before animals are handled. Advance

124 preparation must include implemented protocols for addressing personnel. Once an

125 animal has been slaughtered, death must be carefully verified. All laws and regulations

126 pertaining to the species being slaughtered must be followed.

127 Humane slaughter must be performed in accord with applicable federal, state, and

128 local regulations governing occupational health and safety. The AVMA encourages all

129 personnel responsible for humane slaughter to review current federal, state, and local

130 regulations. Special attention to species requirements during handling, stunning and

131 rendering an animal unconscious should be observed.

132 Evaluating Slaughter Methods

133 Some methods of slaughter may require physical handling of the animal. The amount

134 of control and the kind of restraint required will be determined not only by the species, breed

135 and size of animal involved but also the level of excitement and prior handling experience of

136 the animal and competence of the person(s) performing animal slaughter. Proper handling is

137 vital to minimize pain and distress in animals, to ensure the safety of the person performing

138 euthanasia, and, often, to protect other people and animals.

139 Selection of the most appropriate method of humane slaughter in any given

140 situation depends on the species and number of animals involved, available means of

141 animal restraint, skill of personnel, and other considerations. Personnel who slaughter

142 animals for food must demonstrate proficiency in the use of the technique in a closely

143 supervised environment. Each facility where slaughter is performed is responsible for

144 appropriately training its personnel. Furthermore, experience in the humane restraint of the

145 species of animal is critical. Training should include familiarity with the normal

146 behavior of the species, an appreciation of how behavior affects handling and

147 restraint, and an understanding of the mechanism by which the selected technique induces

148 loss of consciousness, and death.

149 It is imperative that unconsciousness be verified before hoisting, shackling or cutting

150 beings. Death must be verified before invasive dressing begins (or before disposal of the

151 animal for meat quality reasons). Relevant personnel must be sufficiently trained to

152 recognize the cessation of vital signs of different animal species.

153 The POHS gave consideration to the following criteria in their assessment of the

154 slaughter methods: (1) ability to induce loss of consciousness followed by death with a

155 minimum of pain or distress; (2) time required to induce loss of consciousness and

156 the behavior of the animal during that time, especially for religious slaughter; (3)

157 reliability and irreversibility of the methods resulting in death of the animal; (4) safety of

158 personnel; (5) compatibility with intended animal use and purpose (i.e., meat

159 consumption); (6) human abuse or potential psychological or emotion impacts on

160 personnel; (7) ability to maintain equipment in proper working order; and (8) legal

161 and religious requirements.

162 Circumstances may arise that are not clearly covered by these Guidelines. Whenever

163 such situations arise, a veterinarian experienced with the species should apply professional

164 judgment, and knowledge of clinically acceptable techniques in selecting an appropriate

165 technique to end an animal's life in the most humane way possible. The veterinarian should

166 consider if the procedure results in the best outcome for the animal, whether his/her actions

167 conform to acceptable standards in veterinary practice and if they are consistent with her/his

168 professional obligations and ethical commitment to the public.

169 Stress and Distress, Unconsciousness, and Pain

170 These Guidelines acknowledge that a humane approach to the slaughter of any

171 creature is warranted, justifiable, and expected by society. The overall goal should be to

172 minimize or eliminate pain, anxiety and distress prior to loss of consciousness. Therefore,

173 both the induction of unconsciousness as well as the overall handling process prior to

174 slaughter must be considered. Criteria for determining humaneness of a particular

175 slaughter method can be established only after the mechanisms of distress, pain, and

176 consciousness are understood. For a more extensive review of these issues, the reader is

177 directed to the latest version of the 2012 AVMA Guidelines on Euthanasia (in press).

178 Humane slaughter methods produce unconsciousness through four basic

179 mechanisms: (1) physical disruption of brain activity (e.g., blunt cranial trauma,

180 penetrating captive bolt, gunshot); (2) hypoxia (e.g., controlled low atmospheric pressure

181 for poultry, N2, Ar, exsanguination); (3) direct depression of neurons necessary for life

182 function (e.g., CO2), or (4) Epilepitiform brain activity (e.g. electric stunning). As loss of

183 consciousness resulting from these mechanisms can occur at different rates, the suitability

184 of a particular agent or method will depend on the species and whether an animal

185 experiences pain or distress prior to loss of consciousness.

186 Distress during slaughter may be created by the method itself or by the conditions

187 under which the method is applied, and may manifest behaviorally (e.g., overt escape

188 behaviors, approach-avoidance preferences [aversion]) or physiologically (e.g., changes

189 in heart rate, sympathetic nervous system [SNS] activity, hypothalamic-pituitary axis

190 [HPA] activity). Stress and the resulting responses have been divided into three phases

191 (Breazile, 1987). Eustress results when harmless stimuli initiate adaptive responses that

192 are beneficial to the animal. Neutral stress results when the animal’s response to stimuli

193 causes neither harmful nor beneficial effects to the animal. Distress results when an

194 animal’s response to stimuli interferes with its well-being and comfort (McMillan, 1998).

195 Although SNS and HPA activation are well-accepted as stress response markers, these

196 systems are activated in response to both physical and psychological stressors and are not

197 necessarily associated with higher order CNS processing and conscious experience by the

198 animal. Furthermore, use of SNS and HPA activation to assess distress during application

199 of Controlled Atmosphere (CAS) methods is complicated by continued exposure during

200 the period between loss of consciousness and death (AVMA, 2013).

201 Ideally, humane stunning and/or killing methods result in rapid loss of

202 consciousness and the associated loss of brain function. The perception of pain is defined

203 as a conscious experience (Antognini et al., 2005) and requires nerve impulses from

204 peripheral nocioceptors to reach a functioning conscious cerebral cortex and the

205 associated subcortical brain structures. The International Association for the Study of

206 Pain (IASP) describes pain as “an unpleasant sensory and emotional experience

207 associated with actual or potential tissue damage, or described in terms of such damage.

208 Activity induced in the nocioceptor and nociceptive pathways by a noxious stimulus are

209 not pain, which is always a psychological state, even though we may well appreciate that

210 pain most often has a proximate physical cause.” (IASP, 2011). Pain is therefore

211 subjective in the sense that individuals can differ in their perceptions of pain intensity as

212 well as in their physical and behavioral responses to it.

213 Distress during administration of CO, CO2 and the inert gases N2 and Ar has been

214 evaluated using both behavioral assessment and aversion testing and reviewed in the

215 context of euthanasia (AVMA, 2013). It is important to realize that aversion is a measure

216 of preference, and while aversion does not necessarily imply that an experience is

217 painful, forcing animals into aversive situations creates stress. The conditions of exposure

218 used for aversion studies, however, may differ from those used for stunning or killing.

219 One of the characteristics of anesthesia in humans is the feeling as if one is having an out

220 of body experience, suggesting a disconnection between one’s sense of self and one’s

221 awareness of time and space (Alkire et al., 2009); although we cannot know for certain

222 the subjective experiences of animals, one can speculate similar feelings of disorientation

223 may contribute to the observed signs of distress with inhaled methods. In addition, agents

224 identified as being less aversive (e.g., Ar or N2 gas mixtures) can still produce overt signs

225 of behavioral distress (e.g., open mouth breathing) for extended time periods prior to loss

226 of consciousness under certain conditions of administration (e.g., gradual displacement)

227 (Webster and Collett, 2012).

228 Unconsciousness, defined as loss of individual awareness, occurs when the

229 brain’s ability to integrate information is blocked or disrupted. In animals, loss of

230 consciousness is functionally defined by loss of the righting reflex (LORR), also called

231 loss of position/posture (LOP) (Hendricks et al., 2008; Antognini et al., 2005, Zeller et

232 al., 1988 as cited by Raj 1990). This definition is still quite useful because it is an easily

233 observable, integrated whole animal response. Although any physical movement

234 occurring during anesthesia, euthanasia, slaughter, or depopulation is often interpreted as

235 evidence of consciousness, cross-species data from the anesthesia literature suggest that

236 both memory formation and awareness are abolished early in the overall process relative

237 to loss of reflex muscle activity (Antognini et al., 2005). Thus, vocalization and non-

238 purposeful movement observed after LORR/LOP with properly applied CAS methods are

239 not necessarily signs of conscious perception by the animal. While generalized seizures

240 may be observed following effective CAS methods, these generally follow loss of

241 consciousness; indeed, anesthesia, coma, and generalized seizures all represent a loss of

242 consciousness where both arousal and awareness in humans is low or absent (Cavanna et

243 al., 2011). Loss of consciousness should always precede loss of muscle movement.

244 Although measurements of brain electrical function have been used to quantify

245 the unconscious state, EEG data cannot provide definitive answers as to onset of

246 unconsciousness using the current state of the art equipment. At some level between

247 behavioral unresponsiveness and the induction of a flat EEG (indicating the cessation of

248 the brain’s electrical activity and brain death) consciousness vanishes. However, current

249 EEG-based brain function monitors are limited in their ability to directly indicate

250 presence or absence of unconsciousness, especially around the transition point (Alkire et

251 al., 2008; Mashour et al., 2011); also, it is not always clear which EEG patterns are

252 indicators of activation by stress or pain (Hawkins et al., 2006). Reduction in alpha:delta

253 brain wave ratios coincides with LOP in chickens (McKeegan et al., 2011; Benson et al.,

254 2012), reinforcing the usefulness of LOP/LORR as an easily observable proxy for loss of

255 animal consciousness.

256 Physical methods that destroy or render nonfunctional the brain regions

257 responsible for cortical integration (e.g., gunshot, captive bolt, cerebral induction of

258 epileptiform activity in the brain [e.g., electric stunning], blunt force cranial trauma,

259 maceration) produce instantaneous unconsciousness. When physical methods directly

260 destroy the brain, signs of unconsciousness include immediate collapse (LORR/LOP) and

261 a several-second period of tetanic spasm, followed by slow hind limb movements of

262 increasing frequency (Gregory et al., 2007; Finnie, 1995; Blackmore and Newhook,

263 1983) in cattle; however, there is species variability in this response. The corneal reflex

264 will also be absent (Gregory, 2007). Signs of effective electric stunning which induces

265 both epileptiform activity in the brain and cardiac arrest are LORR, loss of menace reflex

266 and moving object tracking, extension of the limbs, opisthotonos, downward rotation of

267 the eyeballs, and tonic spasm changing to clonic spasm, with eventual muscle flaccidity

268 (Vogel et al., 2010; Blackmore and Newhook, 1983). Physical methods are inexpensive,

269 humane, and painless if performed properly, and leave no drug residues in the carcass.

270 Furthermore, animals presumably experience less fear and anxiety with methods that

271 require little preparatory handling. However, physical methods usually require a more

272 direct association of the operator with the animals, which can be offensive to, and

273 upsetting for, the operator. Physical methods must be skillfully executed to ensure a

274 quick and humane death because failure to do so can cause significant stress, distress, and

275 pain. Physical disruption methods are usually followed by exsanguination to ensure death

276 and improve meat quality. Exsanguination is also a method of inducing hypoxia, albeit

277 indirectly.

278 Controlled atmosphere (CAS) methods also depress the cerebral cortical neural

279 system, producing loss of consciousness accompanied by LORR/LOP. Purposeful escape

280 behaviors should not be observed during the transition to unconsciousness. Depending on

281 the speed of onset of unconsciousness, signs associated with release of conscious

282 inhibition of motor activity, (such as vocalization or uncoordinated muscle contraction)

283 may be observed at LORR/LOP. Signs of an effective stun are similar to those observed

284 with the physical methods or with deep levels of anesthesia, including LORR/LOP, loss

285 of eye blink and corneal reflex, and muscle flaccidity (Grandin, 2010). As with physical

286 disruption methods, CAS methods are usually followed by exsanguination to ensure

287 death and improve meat quality.

288 Decapitation and cervical dislocation as physical methods of slaughter that require

289 separate comment. The interpretation of brain electrical activity, which can persist for up

290 to 30 seconds following these methods (Cartner et al., 2007; Vanderwolf et al., 1988;

291 Mikeska and Klemm, 1975), has been controversial (Bates, 2010). As indicated

292 previously, EEG methods cannot provide definitive answers as to the exact onset of

293 unconsciousness. Other studies indicate such activity does not infer the ability to perceive

294 pain and conclude that loss of consciousness develops rapidly (Holson, 1992; Derr,

295 1991;Vanderwolf et al., 1988; Mikeska and Klemm, 1975; van Rijn et al., 2011).

296 In summary, the cerebral cortex or equivalent structure(s) and associated

297 subcortical structures must be functional for pain to be perceived. If the cerebral cortex is

298 nonfunctional because of physical disruption, hypoxia, generalized epileptic seizure, or

299 neuronal depression, pain cannot be experienced. Motor activities occurring following

300 LORR/LOP, although potentially distressing to observers, is not perceived by an

301 unconscious animal as pain or distress. Reflexive kicking in unconscious animals may be

302 mistaken for conscious activity and can occur even after decapitation as neurological

303 circuits involved with walking are located in the spinal cord (Grillner, 2011). Given that

304 we are limited to applying slaughter methods based on these four basic mechanisms,

305 efforts should be directed toward educating individuals involved in the slaughter process,

306 achieving technical proficiency, and refining the application of existing methods,

307 including handling conditions prior to slaughter.

308 Animal Behavioral Considerations

309 These Guidelines are concerned with minimizing animal distress, including

310 negative affective or experientially-based states such as fear, aversion, anxiety, and

311 apprehension, during the slaughter process. Veterinarians and related employees conducting

312 slaughter should familiarize themselves with pre-slaughter protocols and be attentive to

313 species and individual variability in order to mitigate distress, and promote animals and

314 human welfare, and human safety. The method for inducing unconsciousness and the

315 handling and restraint method associated with it must be evaluated as an entire system

316 (Grandin, 2012). Physical methods require more handling and restraint of individual animals

317 compared to CAS but they induce instantaneous unconsciousness. Controlled atmosphere

318 stunning (CAS) does not induce instantaneous unconsciousness but possible distress during

319 handling may be reduced. There may be a tradeoff between possible distress during a longer

320 time to induce unconscious and the benefits of reduced handling of individual animals.

321 Violations of the HMSA must not be tolerated. At all stages of the process, animals

322 should be treated with respect, and compromises to animal welfare should be treated as

323 unacceptable if not unlawful. Practitioners and stockpersons should ensure that:

324 No conscious animal is moved, shackled, hoisted or cut inappropriately. Before

325 invasive dressing are started all signs of brain stem function, such as the corneal

326 reflex must be abolished by bleeding.

327 Excessive force or frequent use of electric prods to move animals off trucks, down

328 ramps or into slaughter facilities or restraint devices is avoided. Animals should

329 not be forced to move faster than a normal walking speed. Handlers should move

330 animals quietly.

331 Non-ambulatory or disabled animals are isolated and moved with suitable

332 equipment and provided appropriate veterinary attention. Conscious non-

333 ambulatory animals must never be dragged.

334 Terrestrial animals are provided with access to water in the lairage pens and they

335 should have sufficient room to move in accordance with state, federal and local

336 statues and have room for all the animals to lie down.

337 Slaughter facilities and equipment are well maintained to minimize injury or pain

338 to the animals and employees

339 The induction of unconsciousness (e.g., stunning) causes minimal distress to the

340 animal.

341 All personnel are trained in both the application of stunning methods and

342 behavioral principles of animal handling.

343 Human Behavioral Considerations

344 Food sector practitioners may be asked to bridge the physical and psychological

345 divide between food animals and consumers by communicating the nature of

346 conventional food production. They may also be asked to provide an ethical accounting

347 and monitoring of animal welfare standards on the farm, in feedlots, in aqua-farms and at

348 slaughterhouses to the public in a transparent fashion. Food animal veterinarians are

349 encouraged to increase awareness of slaughter methods and to enhance understanding of

350 the science behind the methods currently employed with a view towards the day-to-day

351 complexities of managing food animals and the range of challenges facing our

352 contemporary food animal sector. Likewise, industry agents, veterinarians, caretakers

353 and others related to the slaughter of animals for food should be encouraged to

354 understand the diversity of public concerns and trending societal values related to how

355 animals are farmed and slaughtered for food.

356 The humane slaughter of animals is a learned skill that requires training, respect,

357 and self-awareness. Personnel performing humane slaughter must be technically

358 proficient. Periodic professional continuing education on the latest methods, techniques

359 and materials available for slaughter is highly encouraged. Personnel must also possess a

360 particular kind of temperament that does not bolster brutality, for example. Self-

361 awareness when it comes to processing animals for food will help to mitigate compassion

362 fatigue and callousness.

363 The killing of individual livestock or poultry by farm workers who are also

364 responsible for providing husbandry can substantially impact emotions (Woods et al., 2010).

365 Therefore, appropriate oversight of the psychological well-being of slaughter employees is

366 paramount to mitigate guilt, distress, sadness, fatigue, alienation, anxiety and behaviors that

367 lack consideration of others or may lead to harming to themselves or others. People may

368 have individual differences in how they psychologically react to the job of killing animals

369 (Grandin, 1988). It is difficult to care about animals when they have to be killed. This is

370 called the “caring killing paradox” (Arluke, 1994).

371 Veterinarians and staff who are regularly exposed to the slaughter process should

372 also be monitored for emotional burn-out, psychological distress or compassion fatigue, and

373 be encouraged to seek appropriate psychological counseling (Rhoades, 2004; Manette, 2004).

374 While integrating good animal welfare in the food chain, some food animal practitioners may

375 be torn between serving the best interest of farmed animal, the human client (individual),

376 personal professional interests, societal concern to improve the quality of life of animals/or

377 for safe and affordable animal protein. More studies on both the impact of animal slaughter

378 on the personnel performing the procedure, and on consumption of animals within the

379 general public will go a long way in promoting healthier and more respectful human-food

380 animal relationships.

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445 McKeegan DE, Sparks NH, Sandilands V, et al. Physiological responses of laying hens 446 during whole-house killing with carbon dioxide. Br Poult Sci. 2011;52(6):645-657.

447 McMillan FD. Comfort as the primary goal in veterinary medical practice. J Am Vet Med 448 Assoc 1998;212:1370-1374.

449 Mikeska JA, Klemm WR. EEG evaluation of humaneness of asphyxia and decapitation 450 euthanasia of the laboratory rat. Lab Anim Sci 1975;25:175-179.

451 Rose JD. The neurobehavioral nature of fishes and the question of awareness and pain. 452 Rev Fish Sci 2002;10:1-38.

453 Rose JD. Anthropomorphism and ‘mental welfare’ of fishes. Dis Aquat Org 454 2007;75:139-154.

455 Rhoades RH. The HSUS Euthanasia. In: Rollin BE, Benson GJ, eds. Improving the well- 456 being of farm animals: maximizing welfare and minimizing pain and suffering. Ames, IA: 457 Blackwell Publishing, 2004; p. 351-362.

458 Vanderwolf CH, Buzak DP, Cain RK, et al. Neocortical and hippocampal electrical 459 activity following decapitation in the rat. Brain Res 1988;451:340-344.

460 van Rijn CM, Krijnen H et al. Decapitation in rats: latency to unconsciousness and the 461 ‘wave of death’. PLoS ONE. 2011;6(1):e16514

462 Vogel KD, Badtram G, Claus JR, et al. Head-only followed by cardiac arrest electrical 463 stunning is an effective alternative to head-only electrical stunning in pigs. J Anim Sci 464 2011.

465 Webster AB, Collett SR. A mobile modified-atmosphere killing system for small-flock 466 depopulation. J Appl Poult Res 2012; 21:131-144.

467 Woods J, Shearer JK, Hill J. Recommended on-farm euthanasia practices. In: Grandin T, 468 ed. Improving animal welfare: a practical approach. Wallingford, Oxfordshire: CABI 469 Publishing, 2010.

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476 Regulations, Oversight and Training

477 Regulations of Slaughter in the United States

478 The Federal Meat Inspection Act of 1906 (as amended) requires USDA to inspect

479 all cattle, sheep, swine, goats, and horses brought into any plant to be slaughtered and

480 processed for human consumption (Rawson, 2002). The FMIA does not cover poultry;

481 mandatory inspection of poultry products for human consumption did not become

482 mandatory until passage of the 1957 Poultry Products Inspection Act (PPIA; Rawson,

483 2002). The 1978 Humane Methods of Livestock Slaughter Act (HMSA) made

484 mandatory the humane slaughter and handling of livestock in connection with slaughter

485 of all food animals slaughtered in USDA inspected plants. Animals included under the

486 1978 Act include: cattle, calves, horses, mules, sheep, goats, swine, and other livestock.

487 Two methods of slaughter were determined to be humane under the 1978 Act. The first

488 requires that livestock are rendered insensible to pain on the first application of the

489 stunning device before being shackled, hoisted, cast, or cut. The second method is in

490 accordance with the ritual requirements of any religious faith that prescribes a method of

491 slaughter where the animal suffers loss of consciousness by anemia of the brain caused

492 by the simultaneous and instantaneous severance of the carotid arteries with a sharp

493 instrument. Additionally, Section 1906 exempts the handling or other preparation of

494 livestock for slaughter under the second method, from the terms of the Act. Therefore,

495 the statutory requirement that livestock are rendered insensible to pain prior to shackling,

496 hoisting, casting, or cutting does not apply to the handling or restraint that is immediately

497 associated with the cut when the second method of slaughter is being used. Examples of

498 this type of slaughter include Jewish (Kosher) slaughter and Islamic (Halal) slaughter

499 (FSIS, 2009).

500 Currently, the HMSA of 1978 does not cover poultry. However, welfare practices

501 for poultry are covered by the regulatory requirement for good commercial practices

502 (GCP).

503 These regulations can be found in 9 CFR Part 381 (Poultry Products Inspection

504 Regulations; FSIS, 2009). In the PPIA, a poultry product is adulterated if, among other

505 circumstances, it is in whole, or in part, the product of any poultry which has died by a

506 method other than slaughter. Therefore, poultry that are still breathing on entering the

507 scalder and die from drowning and not from slaughter and are considered adulterated and

508 unfit for human food and are condemned. Furthermore, in 2005, USDA published a

509 Federal Register Notice (Docket No. 04-037N) on the treatment of live poultry before

510 slaughter. USDA defined a “systematic approach” as one in which establishments focus

511 on treating poultry in such a manner as to minimize excitement, discomfort, and

512 accidental injury during the time that live poultry are held in connection with slaughter.

513 (FSIS, 2009) Currently, this approach is voluntary on the part of industry. A provision

514 in the USDA appropriations act for fiscal year 2001 (P.L. 106-387) amended the PPIA to

515 include mandatory FSIS inspection for meat from ratites and quail (Rawson, 2002).

516 Regulations for the voluntary inspection of exotic animals can be found under 9

517 CFR 352.10. The authority for the inspection of exotic animals comes from the

518 Agriculture Marketing Act (AMA) of 1946 found in 7 U.S.C. 1621 et seq., which

519 promotes distribution & marketing of agricultural products (includes exotic species not

520 under FMIA). Livestock specified under these regulations include: antelope, bison,

521 buffalo, catalo (cattalo), and deer. Exotic animals that are defined by these regulations

522 are: reindeer, elk, deer, antelope, water buffalo or bison. This section includes

523 regulations that address humane handling during antemortem inspection and stunning

524 practices to render the animals unconscious that are consistent with the regulations

525 pertaining to the 1978 HMSA (9 CFR 313.15 or 313.16).

526 Many countries have set standards for welfare practices with regard to humane

527 slaughter. However, we are just beginning to see these differing standards play a role in

528 global trade. The EU’s “Strategy for the Protection and Welfare of Animals” not only

529 lays a foundation for improving welfare standards in the EU and making sure that those

530 standards are applied and enforced in all EU countries, but also plans to apply equivalent

531 welfare standards to imports from other countries in the future (Gavinelli, 2012).

532 Oversight of Humane Slaughter by the USDA/FSIS and Private Industry

533 The FSIS (Food Safety Inspection Service) of the U.S. Department of Agriculture

534 (USDA) is mandated to enforce humane slaughter regulations and directives. In the

535 1980s and 1990’s, enforcement was lax. In 1997, a survey was conducted for the USDA

536 (Grandin, 1997, 1998). Only three out of ten beef plants were capable of rendering cattle

537 unconscious with a single shot from a captive bolt. The main cause of poor captive bolt

538 stunning was lack of maintenance (Grandin, 1998). There were numerous other problems

539 observed in the 22 beef, pork, lamb, and veal plants that were surveyed (Grandin, 1997,

540 1998).

541 A scoring system that was developed for use in this survey became the basis of

542 the voluntary industry guidelines published by the American Meat Institute (AMI). The

543 first version was published in 1997 and the most recent complete version is in Grandin

544 (2012). The guideline measures five outcome measures. The use of outcome based

545 measurements to assess animal welfare is recommended (Hewson, 2003; Webster, 2005;

546 Wray et al., 2003). Below is a summary of the five major measurements (Grandin,

547 2010).

548 1. Percentage of animals rendered unconscious with a single shot from a captive bolt

549 or percentage of animals where the electric stunner is placed on the head in the

550 correct position. The minimum acceptable score is 95% first shot efficacy for

551 captive bolt and 99% correct positioning for electric stunning.

552 2. Percentage of animals rendered unconscious before hoisting to the bleed rail. To

553 pass an audit, 100% unconsciousness is required on a sample of 100 animals.

554 There is a zero tolerance for starting invasive procedures such as skinning or leg

555 removal on an animal showing any signs of return to consciousness.

556 3. Percentage of cattle and pigs that remain silent and do not vocalize (bellow, moo

557 or squeal) in the stunning area. To pass an audit, 95% of the cattle or pigs must

558 remain silent in the stun box, conveyor restrainer or during restraint for religious

559 slaughter. Refer to Grandin 2012 for more detailed information on scoring

560 vocalization. Do not use vocalization scoring for sheep.

561 4. Percentage of animals moved without an electric prod. The minimum acceptable

562 score is 75% of the animals moved with no electric prod use. An excellent score

563 is 95%.

564 5. Percentage of animals that remain standing and do not fall during handling. A

565 score of a fall is given if the body touches the ground. Restrainer devices that are

566 designed to trip animals and make them fall are not acceptable. The minimum

567 acceptable score is 99% handled with no falling. Falling is scored in all parts of

568 the facility.

569 There are also four acts of abuse which should never be tolerated: 1) dragging

570 non-ambulatory animals (also a HMSA violation); 2) beating animals; 3) poking sensitive

571 areas such as eyes, nose, udder, or anus; 4) deliberately driving animals over the top of

572 other animals or deliberately slamming gates on animals.

573 In 1999, the use of this scoring system by major meat buying customers resulted

574 in great improvements. A year after McDonalds Corporation and Wendy’s International

575 started using the objective scoring system, over 90% of the beef plants were able to

576 render 95% of the cattle unconsciousness with a single shot (Grandin, 2000, 2005). The

577 use of electric prods and the percentage of animals vocalizing was also greatly reduced

578 (Grandin, 2005, 2011).

579 Shortly after the restaurant companies started auditing their supplier plants, the

580 FSIS implemented a program where veterinarians dedicated to inspecting plants for

581 humane treatment were hired. Each inspection district was assigned a veterinarian who

582 was dedicated to traveling to plants in his/her district to conduct humane slaughter audits,

583 and solve humane slaughter problems and by the latter part of the 2000’s, FSIS greatly

584 increased enforcement of the HMSA. This resulted in reports from the industry that

585 enforcement was very uneven and varied greatly from district to district. The GAO

586 (General Accounting Office) did a survey and verified that enforcement was uneven and

587 varied greatly (GAO, 2010). The issues associated with uneven enforcement were

588 greater in small plants compared to larger plants.

589 FSIS responded by publishing a directive that defined egregious animal abuse.

590 When an egregious abuse occurs, the plant can be shut down by suspending inspection

591 (i.e. the plant cannot operate). Some of the acts defined as egregious were clearly stated

592 and others were vague, such as excessive electric prod use. There was a serious incident

593 where suspension of inspection resulted in suffering and death of livestock from heat

594 stress. To prevent these types of problems, FSIS issued a directive giving field inspectors

595 the discretion to postpone a suspension so that animals that were in the transport pipeline

596 can be processed (FSIS, 2011). This directive is reducing uneven enforcement and

597 provides field inspectors with clearer guidance (FSIS, 2011). The directive has an

598 attached facilitator guide that contains a series of scenarios of situations where

599 suspension of inspection is warranted and situations where suspension is not warranted

600 which is used for training inspectors (Facilitator Guide, 2011). For example, if a first shot

601 with a captive bolt was not effective, the plant would not be suspended if a loaded backup

602 captive bolt or a larger caliber firearm was immediately available. This would indicate

603 that they had a robust systematic approach to animal welfare.

604 Important elements for a systematic approach are: maintenance logs on stunners,

605 training programs for employees, in-house and auditing using accepted industry auditing

606 methodologies and video auditing (FSIS Directive 69002, Revision 2, 2011). Individual

607 plants can vary on the structure and elements of their systematic approach and so, each

608 plant will need to develop its own systematic approach program. Writing a systematic

609 approach program for humane slaughter and handling is similar to writing a HACCP plan

610 for food safety. Management inspectors and auditors should conduct direct observations

611 to insure that the plant employees are following their plant’s written program. A robust

612 systematic approach for humane slaughter must be a program of procedures that are

613 actually being done in the plant. There should also be records to show that the checks

614 have been conducted, and to insure that the procedures are being followed. Some other

615 critical areas for a robust systematic approach are nonslip floors on unloading ramps and

616 in stun boxes, electric prod use and handling of downed non-ambulatory animals. Many

617 inspectors also use the AMI objective scoring system to determine which plants have

618 severe problems.

619 Clear Comments

620 When a problem is observed, it is essential that both FSIS inspectors and private

621 auditing companies write clear comments describing exactly what they observed. When

622 return to sensibility is observed, it is essential to not confuse corneal reflex, nystagmus

623 and natural blinking (menace reflex). An animal that has a weak corneal reflex after

624 electric stunning is usually unconscious but after captive bolt or gunshot the corneal

625 reflex must be absent. An animal that has natural blinking like a live animal in the

626 lairage is definitely sensible. This applies to all types of stunning methods.

627 An example of a poor description in an inspection report would be “rough

628 handling.” An example of a clear description of an abusive handling incident would be

629 “a plant employee kicked a pig very hard like kicking a football” or “a plant employee

630 deliberately poked a stick into a steer’s eye”. Clear comments are essential when there

631 are disagreements between FSIS inspection personnel or auditing firms over suspension,

632 or being delisted as an approvedsupplier. It is impossible for supervisors and managers

633 to determine if egregious animal abuse occurred if it is not clearly described. The FSIS

634 Directive 6900.2 Revision 2 has two excellent examples of clear descriptions of an

635 egregious situation of inhumane handling in attachments 4 and 5.

636 Video Auditing by Industry

637 Two major meat companies have installed video cameras that are monitored by a

638 private third party auditing company. The use of video auditing helps prevent the

639 problem of employees following correct procedures when they are being watched and

640 then reverting to bad methods after the inspector or auditor is gone. Video auditing is

641 most effective when it is done by a third party auditor over the internet. Experience has

642 shown that internal video auditing programs are less effective.

643 References

644 Food Safety Inspection Service. Humane handling of livestock and good commercial 645 practices in poultry. 2009. Available at: http://www.fsis.usda.gov/PDF/FSRE-HH- 646 GCP.pdf Accessed: September 14, 2012.

647 Food Safety Inspection Service. Facilitator guide for situation based humane handling 648 training, FSIS. Beltsville, MD. November 14, 2011.

649 Food Safety Inspection Service. Directive 6900.2, Revision 2, 2011 Humane Handling 650 and Slaughter of Livestock. August 15, 2011.

651 Gavinelli A. Develepoments in AW policies in the EU: everyone is responsible. Seminar 652 of the European Institute on Animal Welfare: Market-driven Animal Welfare in the EU 653 and the US. Cosmos Club, Washington D.C. March 22, 2012. Presentation available at: 654 http://www.slideshare.net/EUintheUS/washington-andrea-1.

655 General Auditing Office. Humane methods of slaughter act. February 2010. Available at: 656 http://www.gao.gov/assets/310/300921.pdf. Accessed October 17, 2012.

657 Grandin T. Survey of Stunning and Handling in Federally Inspected Beef, Veal, Pork, 658 and Sheep Slaughter Plants, United States Department of Agriculture 659 (USDA/Agricultural Research Service Project 3602-32000-002-08G. 1997a. USDA, 660 Beltsville, Maryland.

661 Grandin T. Objective scoring of animal handling and stunning practices at slaughter 662 plants, JAVMA. 1998;212:6-39.

663 Grandin T. Effect of animal welfare audits of slaughter plants by a major fast food 664 company on cattle handling and stunning practices, JAVMA, 2000;216:848-851.

665 Grandin T. Maintenance of good animal welfare standards in beef slaughter plants by use 666 of auditory programs. JAVMA. 2005;226:370-373.

667 Grandin T. Auditing animal welfare at the slaughter plants. Meat Sci. 2010;86:56-65.

668 Grandin T. Recommended Animal Handling Guidelines and Audit Guide: A Systematic 669 Approach to Animal Welfare, American Meat Institute Foundation, Washington, D.C. 670 2012. Available at: www.animalhandling.org.

671 Hewson CJ. Can we access welfare? Can Vet J, 2003;44:749-753.

672 Rawson JM. Issue brief for congress: meat and poultry inspection issues. Congressional 673 Research Service, The Library of Congress. August 27, 2002. Available at: 674 http://www.cnie.org/NLE/CRSreports/IB10082.pdf. Accessed September 14, 2012.

675 Webster J. The assessment and implementation of animal welfare: Theory into practice. 676 Review Science and Technology. Off. International Epiz. 2005;24:723-734.

677 Wray HR, Main DCJ, Guen LE et al. Assessment of dairy cow welfare using animal 678 based measures. Vet Rec. 2003;153:197-202.

679 Design of Facilities and Slaughter Process

680 Handling Procedures at Slaughter Plants for Hoofstock

681 Step 1—Arrival at the Plant

682 The normal process is for the animals to be unloaded promptly after a vehicle

683 arrives at the plant. In the best operations, the vehicles are unloaded within 15 to 60

684 minutes after arrival and industry guidelines recommend a maximum wait time of 60

685 minutes (Grandin, 2012). This requires the scheduling of an appointment between the

686 plant and transporter. Scheduling vehicle arrival times prevents the problem of too many

687 vehicles arriving at the same time, which results in long lines and delays at unloading.

688 During hot weather, delayed unloading can result in severe animal welfare problems due

689 to heat stress. Death losses in pigs increase as the internal temperature of the trailer

690 increases (Haley et al., 2008). Figure 1 shows the step-by-step flow of animals through

691 the plant.

692 Detection of Problems

693 There have been unfortunate cases where many cattle or pigs have died while

694 waiting an entire day to unload. This serious problem is most likely to occur when there

695 is an emergency condition such as a power failure or storm, which either shuts down the

696 plant or makes roads impassible.

697 Corrective Action for Problems

698 It is best practice to have an emergency program to divert incoming trucks to

699 either other slaughter facilities or to unload animals at auction markets, feedlots or

700 fairgrounds. This will require a coordinated program that facilitates immediate

701 cancelation of animal loading on the farm and diverts loads that are enroute to other

702 facilities.

703

704 Step 2—Unloading

705 When unloading is done correctly, animals will move off the vehicle in a quiet,

706 orderly manner. Handlers should be quiet and refrain from yelling, whistling or

707 repeatedly hitting the sides of the vehicle. The sound of people yelling has been shown

708 to be very stressful for livestock (Waynert et al., 1999; Pajor et al., 2003). Electric prods

709 can be completely eliminated during unloading of most hoofstock and ducks. The best

710 U.S. sheep plants use trained sheep to lead the animals off the vehicle (T. Grandin,

711 personal communication, 2012). An electric prod may occasionally be necessary to move

712 pigs out of a vehicle with multiple decks. Some pigs may be very difficult to drive and

713 move if they have never had the experience of people walking through their pens on the

714 farm. Handling experiences on the farm can effect pig movement in the future (Grandin,

715 1989; Geverink et al., 1998; Abbott et al., 1997). Pigs that have become accustomed to

716 people walking through their pens on the farm will be easier to move and less likely to

717 pile up when they are handled at the plant (Grandin, 2007). Use of electric prods on

718 horses is strongly discouraged; it should only be a means of last resort when all other

719 options have been exhausted. Acceptable handling tools for horses include but are not

720 limited to: flags and rattle paddles (HWAC, 2010).

721 Detection of Problems

722 If more than 1% of animals fall during unloading, or more than 5% of animal are

723 unloaded using an electric prod there is a welfare problem in the unloading area

724 (Grandin, 2010a,b; Grandin, 2012. Most plants can achieve this standard as the majority

725 of larger plants have banned the use of the electric prod at unloading. There is a serious

726 problem if animals in the unloading area run into fences or pile up. Quiet handling also

727 provides the advantage of greatly reducing bruises (Grandin, 1981) which is an economic

728 incentive for the facility.

729 At the time of unloading, plant employees should note whether or not the vehicle

730 is overloaded. Vehicles should be loaded per industry and international guidelines

731 (Grandin, 2012; FASS, 2010; HWAC, 2010; NPB, 2010).

732 Overloading of trucks can cause severe economic losses. Bruised meat cannot be

733 used for human consumption. In cattle, overloading of trucks will increase bruises,

734 lameness, and the likelihood of non-ambulatory cattle (Eldrige et al., 1988; Tarrant et al.,

735 1988; Petherick and Phillips, 2009; Gonzales et al., 2012). A large survey in both the

736 U.S. and Canada showed that 49% of the cattle trucks arriving at processing plants were

737 overloaded (Warren et al., 2010). Overloading trucks with pigs will increase death losses

738 (Ritter, et al., 2006) and overloading horses will lead to fighting, restlessness, falling and

739 injury (Collins, et al., 2000). Research with sheep indicated that packing sheep too tightly

740 on a vehicle resulted in an increase in animals falling down (Jones et al., 2010). Animals

741 should also be observed for transport induced welfare problems such as frostbite,

742 lacerations or heat stress, and urine scald in pigs. Cattle that are heat stressed will breathe

743 with their mouths open (Mader et al., 2005).

744 Another problem that can seriously compromise animal welfare at the slaughter

745 plant is poor condition of the animal before leaving the farm. Weak, emaciated animals,

746 or severe lameness can make humane handling difficult. A survey of ten cattle auctions

747 showed that 13.3% of cull dairy cows and 3.9% of cull beef cows were severely

748 emaciated (Ahola et al., 2011). Most of the cows sold at these auctions go to slaughter.

749 The USDA does not permit the slaughter of non-ambulatory downed cows (xxx) however

750 pigs and sheep that are not able to walk may be slaughtered. Fatigued pigs, which are

751 unable to walk, will recover if they are rested. There are often big differences between

752 producers on the percentage of fatigued pigs arriving at the plant. Pigs fed high doses (9

753 mg /ton) of the growth promotant ractopamine were harder to handle and had more hoof

754 problems (Marchant et al., 2003; Poletto et al., 2009).

755 Another type of animal that is extremely difficult to handle in a humane manner is

756 neonatal “bob veal” dairy calves that are less than a week old. To make humane handling

757 possible these calves should remain on the farm until they are old enough to walk easily

758 without assistance from a person.

759 Corrective Action for Problems

760 Non-slip flooring in the unloading area is essential for all species (Grandin, 2010

761 a,b; Grandin, 2012). Quiet handling and good welfare is impossible if animals slip and

762 fall. For all species (with the possible exception of birds) a rough broom finish is not a

763 satisfactory non-slip floor. A rough broom finish quickly wears down and becomes

764 smooth and slick. For cattle, bison, and other large animals, an 8 inch by 8 inch (20

765 centimeter by 20 centimeter) diamond pattern with 1 inch (2.5 centimeter) or deeper V

766 grooves is recommended. For the smaller species, such as pigs, deer, or sheep, a good

767 floor finish is to stamp the pattern of a 1 inch (2.5 centimeter) wide opening expanded

768 metal mesh pattern into the concrete. There are other suitable finishes for stamping

769 concrete and all of them are rougher than a broom finish. Epoxy or grit finishes work

770 well for smaller species, but they will not provide sufficient traction for large animals that

771 have become agitated. For existing slick floors, there are several options. In high traffic

772 areas, such as unloading ramps and scales, rubber mats made from woven tire treads can

773 be used. Another option is to construct a steel grating from 1 inch (2.5 centimeter)

774 diameter steel rods welded in a 12 inch by 12 inch (30 centimeter by 30 centimeter)

775 square pattern (Grandin, 2010a). The rods must not be crisscrossed over the top of each

776 other. They must be welded into a flat metal grid, to prevent the hooves from catching

777 under the raised rods which can cause hoof injury. Grooving tools can be rented from a

778 concrete supply firm for re-grooving concrete. More information on flooring and the

779 design of unloading ramps can be found in Grandin and Deesing (2008); Grandin

780 (2010a,b).

781 Meat packers should work with producers and buyers to reduce the numbers of

782 fatigued pigs and unfit animals. Practical experience has shown that the percentage of

783 fatigued pigs can be drastically reduced by three changes in farm production practices –

784 1) walking regularly through finishing pens on the farm to make pigs calmer and easier to

785 handle (Grandin, 2007), 2) change genetic selection criteria to breed pigs with good leg

786 conformation, and 3) using ractopamine at or below labeled dosing (Temple Grandin,

787 2012 personal communication). Research has shown that the number one welfare issue

788 with horses arriving at slaughter is owner neglect that occurred on farm (Grandin, et al.,

789 1999). Packers should clearly communicate back to producers that the shipment of unfit

790 animals is unacceptable and implement a financial penalty for the practice.

791

792 Step 3—Receiving

793 For cattle, unloading areas for large trucks should be designed with at least a 10

794 foot (3 meter) level unloading dock (Grandin, 1990). For hogs and sheep the minimum

795 acceptable level dock is 5 feet (1.5 meter) long (Grandin and Deesing, 2008), and for

796 horses 7 feet (HWAC, 2010). After unloading the normal practice in most plants is to

797 verify that the number of animals on the vehicle matches the paperwork. In some plants,

798 there is an extra handling step of weighing individual animals after unloading however,

799 many plants have eliminated this by weighing the entire truck before unloading.

800 Weighing the entire truck has the advantage of reducing bruising of cattle.

801 In many pork plants, pigs are tattooed with an ID number as they walk off the

802 truck. In most other species, animal identification is maintained by placing the animals

803 from each trailer in their own pen and placing their ID paperwork in a holder on the

804 fence.

805 Detection of Problems

806 The most likely problems that can occur during receiving is pigs piling up and

807 falling during tattooing. For other species, falling, piling up or hitting of fences would be

808 an indicator that handling needs to be improved.

809 Corrective Actions for Problems

810 Provide non-slip flooring for all species. For pigs, redesign the tattoo area. A

811 funnel-shaped chute will result in jamming of animals (Hoendenken, 1976; Grandin,

812 1982). Plants with the calmest, quietest pig tattooing, apply a slap tattoo as pigs exit the

813 36 inch (76 centimeter) truck door side by side.

814

815 Step 4—Lairage

816 This may also be called the stockyards or ante-mortem pens. In most plants,

817 animals are held in the same groups that they traveled with on the trucks, which is the

818 ideal. In large plants, a typical lairage pen holds either one or two entire truckloads. It is

819 important to design the pens to hold a whole number of truckloads as a pen designed to

820 hold 1½ truckloads will invariably end up having two loads jammed into it. When new

821 stockyards are being built, they should be laid out so that there is one-way livestock

822 movement through the yards. Ideally, the unloading ramps are at one end of the yards

823 and the chutes to the stunner are at the other end. One good design is to have all the

824 animals enter the pens from one alley and move to the stunner through the opposite end

825 of the pens. Designs for lairage pens are in Grandin and Deesing (2008) and Grandin

826 (2007). In smaller plants, there may be single or small groups of animals arriving from

827 many different owners. Animals from each owner must either be held in their own small

828 pen or have physical identification (such as eartags, electronic ID, or tattoo) to prevent

829 their identification from becoming mixed up with other animals.

830 The Humane Methods of Livestock Slaughter Act (HMSA) requires that all lairage pens

831 be equipped with water troughs, nipples or other suitable devices so that the animals have

832 access to water. Well-designed and maintained lairage pens will be free of sharp edges

833 that can bruise animals. Recommendations for lairage pen space is 20 square feet (1.87

834 square meters) for cattle, 6 square feet (0.55 square meter) for market weight pigs, 11 to

835 12 square feet (1 to 1.12 square meters) for sows, 5 square feet (0.46 square meter) to 6

836 square feet (0.55 square meter) for sheep depending on size and up to 40 square feet (3.74

837 meters) for mature boars (Grandin, 2012a). The animals should be provided sufficient

838 space so they can all lie down at the same time. Before animals can be moved to the

839 slaughter area, they must have ante-mortem inspection by either a Federal or State

840 inspection employee. In many plants, animals are walked out of the lairage pen past the

841 inspector for ante-mortem inspection. In some plants that process only young fed

842 animals, the inspector examines the animals in the pens as these animals are less likely to

843 be ill. After inspection, the lairage pen is tagged as ready for processing. The exception

844 to this rule is “custom exempt” plants which process animal for personal use by the

845 owner/producer.

846 Detection of Problems

847 The three main problems that can occur in the lairage pens are overstocking of the

848 pens, fighting between animals causing injuries, and animals that become non-

849 ambulatory. Bulls are more likely to fight than steers or cows. Practical experiences with

850 pigs have shown that large groups (over 100 pigs) fight less than small groups. A small

851 group of 5 or 6 pigs in a small pen will sometimes result in prolonged fights. Bison can

852 get into severe fights that result in death. Another problem is animals mounting each

853 other, which may result in weak animals falling down.

854 Correction Action of Problems

855 When fighting occurs, there is usually one animal that is the main perpetrator.

856 This animal should be removed from the group and placed in a separate pen. Intact males

857 of many species will often mount and ride other animals. If a bull is knocking down old

858 cull cows during mounting, he should be removed from the pen. Fighting is a major cause

859 of bruising in horses (Grandin, et al., 1999). In small plants, some of the worst fights

860 arise from singly raised backyard animals that have never learned how to socialize with

861 other animals (Grandin et al, 1999). A good method to prevent fighting is to slaughter

862 bulls and singly raised animals within one hour after arrival after allowing them 30 to 60

863 minutes to calm down. When bulls are finished for beef, they should be kept in the same

864 groups they were raised in. Mixing bulls in the lairage pens will cause meat quality

865 problems (Price and Tennesson, 1981). For pigs, rest in the lairage pens after unloading

866 for two to six hours will enable pigs to recover from transport stress (Brown et al., 1999;

867 Warriss et al., 1992; Milligan, 1998). A lairage time that is too long or no lairage time at

868 all was detrimental to both meat quality and welfare (Perez et al., 2002).

869 The regulations based on the HMSA forbid dragging of non-ambulatory animals

870 unless they have first been stunned. If a non-ambulatory bovine cannot stand and walk,

871 regulations require that it be stunned and sent to rendering. Non-ambulatory pigs, sheep,

872 and other livestock may be moved to either the “suspect” pen or to the “cripple” area in

873 the plant. In the U.S. the only acceptable methods for moving non-ambulatory animals

874 are sled, skid steer loaders or specialized carts. In Canada, non-ambulatory animals must

875 be euthanized on the trailer and cannot be moved with sleds, skid steers or specialized

876 carts. Animals must never be slid along the floor or pushed along the floor by any

877 mechanical device.

878

879 Step 5—Handling System

880 There is a wide variety of different systems to move cattle, pigs, and sheep from

881 lairage pens up to the point where they are stunned or ritually slaughtered (Grandin,

882 2007; Grandin and Deesing, 2008; Gregory, 2007). Systems for deer and other cervids

883 can be found in Matthews (2007) and Haigh (1992, 1995). When handling is done

884 correctly, the animals move in an orderly manner with no falling, pile-ups, vocalizing, or

885 use of electric prods. During the last few minutes before slaughter, excessive use of

886 electric prods can have serious effects on meat quality. Multiple shocks on beef cattle

887 produced tougher meat (Warner et al., 2007). Electric prod use in pigs raises lactate

888 levels (Benjamin et al., 2001) and high lactate levels which occur during the last few

889 minutes before slaughter, will result in lower pork quality (Edwards et al., 2010a;

890 Hambrecht et al., 2005). Jamming of animals in the chute that leads to the stunner along

891 with electric prod use will increase lactate levels (Edwards et al., 2010b). Animals should

892 never be backed into the stun box.

893 Detection of Problems

894 The most obvious abusive handling is by people. Both industry guidelines and

895 USDA/FSIS directives prohibit abusive practices such as dragging downed non-

896 ambulatory animals, poking sensitive areas such as the eyes, anus, or udder, slamming

897 gates deliberately on animals, deliberately driving animals over the top of a downed

898 animal and beating animals (Grandin, 2012). Handling problems that compromise

899 welfare can be caused by either a facility problem or an employee training issue. Before

900 modifications are made to a facility, employees should be trained to use behavioral

901 principles of livestock handing (Grandin and Deesing, 2008; Grandin, 1994). When

902 people handle livestock in a calm quiet manner, design problems in the facility can be

903 easily located and corrected. For all species, if more than 1% of the animals fall at any

904 point in the facility, there is a definite problem that needs to be corrected (Grandin, 1996,

905 2010a,b, 2012). There is a serious problem that needs to be corrected if an automated

906 powered gate causes an animal to either fall down or be dragged along the floor.

907 In cattle and pigs vocalization during restraint, handling, or painful procedures

908 (bellowing, mooing, squealing, whinnying) is associated with physiological measures of

909 stress (Dunn, 1990; White, 1995; Warriss et al., 1994; Weary et al., 1998; HWAC, 2010).

910 Vocalization during cattle handling and restraint at slaughter plants was associated with

911 obvious aversive events such as electric prods, excessive pressure from a restraint device,

912 and sharp edges (Bourquet et al., 2011; Grandin, 1998a). Beef plants with good handling

913 had less than 3% of the cattle vocalizing in the stun box, restrainer, and handled in the

914 lead-up chute (Grandin, 2000, 2005). Plants with serious problems during handling and

915 restraint had 25 to 32% of the cattle vocalizing in this area (Bourquet et al., 2011;

916 Grandin, 1998a,b). In pigs, high levels of squealing in the stunning area were associated

917 with meat quality problems (Warriss et al., 1994). More recent research in slaughter

918 plants showed that vocalizations in cattle were associated with electric prod use

919 (Hemsworth et al., 2011). Excessive use of electric prods can be a major problem. In

920 well managed plants, the average percentages of cattle moved with an electric prod in

921 beef plants with well-trained handlers was 10% entering stun boxes and 16% entering a

922 center track conveyor restrainer (Grandin, 2005). In plants where there is no supervision,

923 electric prod use on nearly 100% of animals is common. In pigs electric prod use varied

924 greatly depending on whether a group of pigs was easy or difficult to drive. On easy to

925 drive pigs an electric prod was used on 4% of the pigs and on a difficult group of pigs

926 20% of the pigs had to be electrically prodded to move them into the single file chute

927 (Grandin 2010a).

928 Corrective Actions for Handling Problems

929 1. Do not overload the crowd pen that leads to the single file race

930 For pigs, cattle, bison, and many other animals, fill the crowd pen that leads to the

931 single file chute half full (Grandin, 2010; Grandin and Deesing, 2008; Grandin, 1999).

932 Cattle, pigs, deer, and bison should be moved into the crowd pen in small separate

933 groups. This principle does not apply to sheep. They should be moved in a large,

934 continuous group due to their intense following behavior.

935 When handling horses in a tub system, the tub should only be filled half full and

936 the crowd gate should never be used to push animals. Handlers should work alongside the

937 tub and single file chute, and overhead catwalks should be avoided. Overfilling the tub or

938 overcrowding with the gate will cause the animals to bunch up and turn back from the

939 single file entry. Animals should be allowed time to move through the system, without

940 being rushed. When the animals are moving through the system themselves, leave them

941 alone. If the lead animal baulks, allow them time to investigate and move forward

942 (HWAC, 2010).

943 2. Use natural following behavior and timing of bunches

944 The next bunch of cattle or pigs should not be brought into the crowd pen that

945 leads to the single file chute until there is space in the single file chute. This enables the

946 animals to immediately enter and promotes natural following behavior (Grandin, 1999)

947 and prevents them from turning around. Unlike domestic cattle and pigs, bison often

948 become agitated while standing and waiting in single file therefore it may be best to put

949 only one or two bison in the single file race at a time.

950 Horses arriving at auction markets and processing plants come from a wide

951 variety of backgrounds and with various degrees of training. This can make them more

952 unpredictable than other species. Handlers should always use caution and treat these

953 animals as though they are untrained. Handlers should approach a horse on the left side,

954 as traditionally horses are trained to be left side dominant. This is due to the fact that

955 most humans are right handed and must stand on the left side of the horse to lead with

956 their right hand. It is important for horses to have visual contact with other horses at all

957 times until they enter the kill box. This will aid in keeping them calm and will motivate

958 them to move forward as their herd mates do (HWAC, 2010).

959 3. Teach handlers behavioral principles

960 Handlers need to understand behavioral principles such as flight zone and point of

961 balance (Grandin 2007; 1980; Kilgour and Dalton, 1984). The most common mistake

962 when moving animals through chutes is a handler who stands at the head of an animal

963 and pokes its rear in an attempt to make it move forward. Standing in front of an animal

964 prevents it from moving forward. Handlers should be taught to use the movement pattern

965 shown in Figure 2 (Grandin, 1998a). When a person quickly walks back past the shoulder

966 of an animal, in the opposite direction of desired movement, the animal will move

967 forward. This is an effective method for many different species.

968 4. Ban constant carrying of electric prods

969 In most plants that have adequate facilities, the only place where an electric prod

970 is occasionally needed is at the entrance to the stun box or restrainer. The prod should be

971 kept in a convenient location and only picked up when needed. After it is used to move

972 the occasional stubborn animal, it should be put away. Alternative driving tools, such as

973 a vibrating prod or plastic paddle should be the handler’s primary driving tool. A

974 vibrating prod can be made from a pneumatic engraving tool where the sharp tip has been

975 removed. A total ban on electric prod is not recommended as a single shock from an

976 electric prod is preferable to hard tail twisting or hitting.

977 5. Careful use of powered gates

978 When powered gates are used to move animals they should be equipped with

979 controls that enable a person to immediately stop movement of the gate if an animal falls

980 down. Automated powered gates must be equipped with pressure limiting devices to

981 prevent the gate from either knocking animal over and dragging animals along the floor.

982 6. Remove Distractions that Cause Balking

983 Movement of animals through a handling facility can often be greatly improved

984 by making many small changes in the facility that remove visual and aural distractions

985 that cause animals to balk and refuse to move (Grandin, 2007; Grandin and Deesing,

986 2008; Grandin, 1996, 1982).

987 a. When an animal enters a stun box or restrainer, it must not have air blowing in its

988 face (Grandin, 2010, 1996).

989 b. Use a directional lamp to provide indirect lighting to light up dark chute

990 entrances. Animals have a tendency to move from a dark place to a brighter place

991 (Van Putten and Elshoff, 1978; Grandin, 1982, 1996).

992 c. Eliminate reflections on shiny metal or wet floors. Moving a light source may

993 eliminate a reflection on a wet floor (Grandin, 1996). Reflected glare from shiny

994 metal surfaces increased balking in cattle plants (Klinglmair et al., 2011).

995 d. Cover the sides of chutes or install solid barriers to prevent approaching animals

996 from seeing people, vehicles or moving machinery up ahead (Grandin, 1996;

997 1987). Experimentation with large pieces of cardboard can be used to determine

998 where solid shields are needed. The outer perimeter of a handling facility is one

999 of the most important areas to cover. Cattle will remain calmer if there is a solid

1000 barrier to prevent them from seeing people standing close to them (Muller et al.,

1001 2008). For flighty species such as deer, the use of solid sides and low lighting will

1002 keep them calmer (Matthews, 2007).

1003 e. Animals often refuse to walk over changes in floor type such as moving from a

1004 concrete to a metal floor. Pigs and cattle are also likely to balk at shadows (Tanida

1005 et al., 1996; Grandin, 1980).

1006 f. Reduce noise made by equipment such as air hissing and metal to metal banging

1007 and clanging. Sudden intermittent sounds and movements are more likely to cause

1008 agitation (Lanier et al., 2000; Talling et al., 1998). Many slaughter plants have

1009 very high noise levels (Weeks et al., 2009).

1010

1011 Step 6—Restraint

1012 Below is a list of design principles to reduce stress during restraint. These

1013 principles are applicable for both conventional slaughter, which uses stunning before

1014 bleeding, and religious slaughter.

1015 1. Optimal pressure – The device must apply enough pressure to make an animal

1016 feel held but avoid excessive pressure that will cause struggling or vocalization. A

1017 common mistake is to apply additional pressure when an animal struggles.

1018 (Grandin, 1992).

1019 2. Do not trigger the fear of falling – This is why nonslip flooring is so important.

1020 When devices are used that hold an animal with its feet off the floor, it must be

1021 held in a balanced, comfortable, upright position. When a device is used that

1022 rotates an animal from an upright position, the body must be securely held and

1023 supported to prevent struggling and slipping within the device. Restrainer

1024 conveyors should be equipped with a false floor to prevent the animals from

1025 seeing the visual cliff effect under the restrainer (Grandin 2007, 1991) as animals

1026 have depth perception and can see the visual cliff (Lemmon and Patterson, 1964).

1027 For a conventional stun boxes where the animal stands upright, non-slip flooring

1028 is critical.

1029 3. Smooth, steady motion of parts of the device that contact the animals – Sudden

1030 jerky motion will cause animals to become agitated (Grandin, 1992).

1031 4. Block vision – To prevent balking and improve ease of entry into the restraint

1032 device, animals entering the device should not be able to see people, moving

1033 equipment, or activity on the processing floor.

1034 5. Appropriate size – Stun boxes must be the appropriate size for the animals being

1035 processed. Animals must not be able to turn around in the box.

1036 Detection of Problems

1037 Vocalization measures can be easily performed in plants to detect problems with

1038 restrainers that are used on cattle, horses or pigs. The animals will vocalize if excessive

1039 pressure is applied or another aversive event occurs (Grandin, 1998a; Bourquet, 2011).

1040 Devices that have serious problems, such as excessive pressure, will have high levels (25

1041 to 32%) of the cattle vocalizing (Grandin, 1998a,b; 1997; Bourquet, et al., 2011). Well

1042 designed and skillfully operated cattle restraint devices that have a head holder will have

1043 5% or less of the animals vocalizing (Grandin, 2010a; 2005). Vocalization scoring

1044 cannot be used in sheep as they usually do not vocalize in response to painful procedures.

1045 If a horse struggles or vocalizes in the restraint it is often an indication that the restraint is

1046 causing discomfort. Active head restraints that clamp an animal’s head are more stressful

1047 for a horse then full body restrainers and should be avoided (HWAC, 2010).

1048 When a restraint system is overloaded beyond its design capacity, the use of

1049 electric prods will increase because handlers are constantly rushing animals. When the

1050 performance of restraint devices is being determined, the device should be scored on the

1051 following variables:

1052 1. Percentage of cattle, horses or pigs that vocalize while entering the restraint

1053 device and the entire time they are held in the restraint device. The American

1054 Meat Institute voluntary industry standard for vocalization is 5% or less of the

1055 animals.

1056 2. Percentage of animals (all species) that fall down where the body touches the

1057 ground. The voluntary industry standard is 1% (Grandin, 2012).

1058 3. Restraint devices that trip animals or are designed to make animals fall are not

1059 permitted in the voluntary industry standard (Grandin, 2012).

1060 4. Percentage of animals moved with an electric prod into the restraint device. The

1061 voluntary industry standard for cattle and pigs is 5% for an excellent score and

1062 25% for an acceptable score. For sheep, the voluntary standard for electric prod

1063 use is 5%. The OIE (World Animal Health Organization) recommends that

1064 electric prods should not be used on sheep, horses, or young calves.

1065 All scores are per animal; the animal is either moved with an electric prod or not. It

1066 is either silent or it vocalizes. Devices that paralyze animals with electricity should not be

1067 used as a method of restraint. Studies clearly show that electro-immobilization is highly

1068 aversive and should not be used (Lambooij and Van Voorst, 1985; Grandin et al., 1986;

1069 Pascoe, 1986, and Rushen, 1986). Electrical immobilization must not be confused with

1070 electrical stunning that causes unconsciousness. Animals that have been immobilized

1071 with electricity will not be able to vocalize to show their distress.

1072

1073 Conditions that Cause Welfare Problems

1074 “In my 35 years of experience, I have learned that there are certain mistakes in

1075 design that people repeatedly make and these things do not work” (T. Grandin, personal

1076 communication).

1077 1. Failure to provide non-slip flooring – One of the most common problems in stun

1078 boxes is slippery floors (Grandin, 1996). When animals are continuously

1079 slipping, they refuse to stand still for stunning. Designs for non-slip floors can be

1080 found in the unloading section. Metal grating works well in stun boxes.

1081 2. Overloading equipment beyond its design capacity – Two of the most common

1082 mistakes are:

1083 a. Overloading a single conveyor restrainer. For a plant to average 1,000

1084 pigs per hour into the cooler, they will need to run the restrainer at 1,200

1085 per hour. In plants, where pigs are forced to move faster than 850 pigs per

1086 hour in a single line, they are moving faster than their normal walking

1087 speed. Most large plants that run 1,000 pigs per hour now have two

1088 conveyor restrainers with two single file chutes and two crowd pens. A

1089 single center track restrainer will work well for the USDA maximum of

1090 390 cattle per hour if it is free of the distractions discussed earlier. At 390

1091 cattle per hour, the cattle are still moving at a normal, slow walk. For both

1092 electric prod use and vocalization, there are few differences for different

1093 line speeds when equipment is designed and operated correctly (Grandin,

1094 2005).

1095 b. Overloading of undersized CO2 stunners. CO2 stunning equipment is

1096 available in many different sizes. One of the most common problems is

1097 plant expansion causing it to outgrow their CO2 stunner. Unless the CO2

1098 stunner is replaced with one a machine with a higher capacity, they are

1099 likely to have the following welfare problems:

1100 i. Overloading gondolas by forcing pigs to jump on top of each other

1101 with electric prods. Pigs should have sufficient room to stand in

1102 the gondola without being on top of each other.

1103 ii. Gas exposure time is reduced in an attempt to increase the number

1104 of pigs the machine can handle per hour. This will result in

1105 sensible pigs emerging from the stunner.

1106 c. Overloading single animal stun boxes and restrainers. It has been found

1107 that single animal stun boxes or restraint boxes have a maximum hourly

1108 speed of approximately 100 per hour. Single animal boxes are slower

1109 than conveyer systems as they use a start-stop process to put each animal

1110 in the box and then remove it. The signs of an overloaded single animal

1111 box are: 1) slamming the rear gate on animals; 2) increased electric prod

1112 use; 3) more than one animal in the box for stunning; and 4) an increase in

1113 rough, abusive handling. For all species, when the line speed exceeds 100

1114 animals per hour, the use of a conveyor system that handles a continuous

1115 stream of animals or two or more single animal boxes is recommended.

1116 3. Funnel-shaped crowd pens – Pigs will jam in a funnel-shaped crowd pen,

1117 therefore a crowd pen that leads to a single file chute should have an abrupt

1118 entrance (Hoenderthen, 1976). The entrance to the single file chute should be just

1119 wide enough to allow one pig to enter. If it is too wide, two pigs may become

1120 stuck beside each other entering the chute. Designs for cattle, sheep, and pig

1121 crowd pens can be found in Grandin (2007, 1992; Grandin and Deesing, 2008;

1122 HWAC, 2010; Sheep Production Handbook, 2002).

1123 4. Stun boxes and single file chutes that are too wide – When people attempt to

1124 guess the correct width for stun boxes and chutes, they tend to overestimate. Stun

1125 boxes and chutes that are too wide result in animals turning around and becoming

1126 jammed beside each other. The correct width is 30 inches (76 centimeters) for

1127 cattle, 18 inches (46 centimeters) for market weight pigs, 32 inches (81

1128 centimeters) for horses, 16 inches (40 centimeters) for sheep, and 27 inches (70

1129 centimeters) for deer. Chute width may need to be adjusted for exceptionally

1130 large or small animals.

1131 5. Vertical overhead gate clearance is too low – Animals will often refuse to walk

1132 under a vertical slide gate or under something that allows for scant clearance or

1133 bumps their back. Raising the opening height 6 in (16 cm) will usually fix this

1134 problem. On center track restrainers, the solid hold down may need to be raised

1135 to prevent bumping of the shoulder when an animal is entering.

1136 6. Single file chute is too short – The single file chute has to be long enough so that

1137 a sufficient number of animals can be held in it to provide time to refill the crowd

1138 pen. For cattle, the following chute lengths are recommended:

Species Line Speed Minimum Length Maximum Length

Cattle Under 25/hr 20 ft (6 m) 75 ft (23 m)

Cattle 25 to 100/hr 40 ft (12 m) 75 ft (23 m)

Cattle 200 to 390hr 80 ft (25 m) 200 ft (23 m)

Pigs and sheep Under 100/hr 10 ft (3 m) 25 ft (7.6 m)

Pigs Over 100/hr 25 ft (7.6 m) 50 ft (15 m)

1139

1140 7. Animals allowed to stand in a stun box too long. Animals should be stunned

1141 immediately after they enter the stun box or restrainer. Holding an animal alone in

1142 a stun box can cause isolation stress.

1143

1144 Handling Procedures at Slaughter Plants for Poultry 1145 1146 Step 1—Electrical and CAS/LAPS- Arrival and lairage

1147 Poultry arrive at the plant and are weighed on a truck scale while they are still on the

1148 vehicle. After weighing, the poultry truck is parked in the lairage shed with the birds still

1149 in the travel containers. The sheds are equipped with fans and misters to keep the birds

1150 cool during hot weather.

1151 Detection of Problems

1152 The most likely problems are overloaded containers, heat stress, frost bite, and death

1153 due to exposure. Other problems that may occur are poorly maintained, broken

1154 containers, which can injure the birds. In extreme cases, birds may be lost on the

1155 highway from broken travel containers.

1156 Correction Action for Problems

1157 Stocking densities for travel containers have been established by both research and

1158 practical experiences. The minimum stocking density gives sufficient space for all birds

1159 to lie down without being on top of each other. The processing plants should have an

1160 emergency plan for birds in case of power failure at the plant or natural disasters that

1161 make roads impassable. Arrangements should be made so that catching and loading of

1162 birds at the farm can be quickly cancelled before loading is started. Loaded shipments

1163 that are already enroute should be diverted to other nearby plants for processing.

1164 Handling and Stunning

1165 The flow chart shows the basic principles of three types of systems. (insert flow chart)

1166

1167 Step 2—Birds moved to stunning area and stunning with CAS and LAPS

1168 CAS Live Unload

1169 This was one of the earliest CAS (controlled atmosphere stunning) systems. In this

1170 system, the live birds in dump module containers are dumped onto a conveyor that

1171 transports them into a gas stunning system. Handling is likely less stressful than hanging

1172 live birds because the birds are shackled after they are anesthetized.

1173 CAS or LAPS in Transport Containers

1174 Most new controlled atmosphere stunning systems are now built as shown in the flow

1175 chart for transport containers. The birds remain in the transport containers as they move

1176 through the system to be anesthetized. Shackling and handling is performed after the

1177 birds are anesthetized. There are various types of CAS or LAPS (Low Atmospheric

1178 Pressure Systems) that are used in transport containers.

1179 Types of CAS and LAPS Chamber Equipment

1180 Anesthetized on the truck

1181 This system is used mostly with turkeys that are transported on trucks with transport

1182 containers that cannot be removed from the vehicle. The vehicle loaded with transport

1183 containers on it pulls into a shed; metal panels clamp onto the side of the vehicle and

1184 CO2 is blown through. As each section is anesthetized, the truck is moved forward and

1185 the next section is stunned while the previous section is being unloaded. The

1186 disadvantage of this system is the need to use a large amount of CO2. The advantage is

1187 that it is economical to build and it could be used with many different types of gasses. It

1188 also enables a turkey company to use existing transport vehicles.

1189 Drawers moved through a tunnel

1190 In this system drawers containing the chickens or turkeys are transferred out of the

1191 racks that contain a series of drawers by automated equipment. The drawers are then

1192 transferred to a conveyor that moves the birds into gradually increasing concentrations of

1193 CO2. This system uses less CO2 than the on-truck system.

1194 LAPS ( Low Atmospheric Pressure System)

1195 Entire racks of either dump modules, drawer modules, or coops are rolled into a

1196 pressure vessel where the air is slowly removed during a three-minute cycle. An

1197 advantage of LAPS is that it will work with all existing chicken transport systems. It is

1198 easy to maintain, there is no expensive gas to purchase, and no carbon environmental

1199 footprint. Most large chicken plants will require more than one chamber. LAPS must

1200 have a full electric stunner back up.

1201 Detection of Problems with CAS or LAPS Stunning of Poultry

1202 Maintaining the correct gas mixtures is essential for birds to have a smooth induction

1203 with a minimum amount of gasping or head shaking. If the birds flap wildly and attempt

1204 to escape from the chamber, is not acceptable (Grandin, 2010a) and may indicate a

1205 problem with the gas mixture. All chamber-type systems for either CAS or LAPS must

1206 have either windows or video cameras so that problems with induction can be observed.

1207 Some discomfort during induction, such as head shaking or gasping may be a reasonable

1208 tradeoff to eliminate live shackling as live shackling is highly stressful (Kannen et al.,

1209 1997; Debut et al., 2005; Bedanova et al., 2007). It is also essential to maintain the

1210 correct dwell times in the chamber to prevent return to consciousness due to a dwell time

1211 that is too short.

1212

1213 Correction of problems with CAS or LAPS

1214 Adjust gas mixtures or LAPS to provide a smoother induction before loss of posture.

1215 Plant management should have a monitoring procedure to visually monitor induction and

1216 record atmospheric parameters. The chamber should have a documented maintenance

1217 protocol for daily, weekly and monthly maintenance. It is strongly recommended that all

1218 chamber-type systems have a full electric stunner backup. This will enable a plant to

1219 keep running if one of their chambers breaks. In systems where there is more than one

1220 chamber this will prevent the temptation to run a single chamber faster to temporarily

1221 replace a broken chamber. In LAPS speeding up the cycle would likely cause severe

1222 stress to the animals. When plants install LAPS or CAS they should purchase sufficient

1223 capacity so that the chambers can be operated with the correct dwell time. If a power

1224 failure or other modification occurs during the stunning process, live birds should be

1225 immediately removed from the chamber.

1226

1227 Step 3—Removal of birds from CAS or LAPS chamber

1228 The palletized containers or the drawers containing the birds are moved to the

1229 shackling area. The birds are unconscious at this point. There are no welfare issues

1230 unless the CAS or LAPS equipment malfunctioned.

1231

1232 Step 2—Birds moved to stunning area for electrical stunning

1233 If a drawer system or individual coops are being used, the drawers or coops are

1234 removed from the palletized rack by automated equipment. They are placed on a

1235 conveyor that runs into the shackle room. Handlers pick up each individual bird and

1236 hang them on the shackle line. If a dump module system is used, a hydraulic platform

1237 operated by an employee tilts the entire palletized container to dump the live birds onto a

1238 conveyor that runs into the shackle room. Handlers pick up live birds and hang them on

1239 the shackle line. The birds are then moved by the shackle conveyor to the water bath

1240 stunner.

1241 Detection of Problems During Unloading and Shackling for Electric Stunning

1242 One problem that can occur with dump modules is unloading the birds too fast,

1243 this results in pile ups and excess birds falling off the conveyor onto the floor. Broken

1244 wings are more likely to occur in heavy birds unloaded from the dump modules

1245 compared to lighter birds. In drawer systems a common problem is crushed heads. This

1246 is caused by rough loading on the farm or poor design of the drawer rack. Another

1247 common problem is understaffing of the shackle line. This results in rough handling and

1248 employees attempting to work too fast, which makes careful handling difficult. When the

1249 shackle line is understaffed, bruised thighs may be observed because employees are

1250 slamming birds into the shackles.

1251 Correction of Problems During Unloading and Shackling for Electric Stunning

1252 A darkened room illuminated with blue lighting will help keep birds calm

1253 (Prescott et al., 2004). Training of the employees who operate the dumper of dump

1254 modules is essential. This employee must learn to wait until the receiving conveyor has

1255 space before dumping more birds. It is also important to never shake the module to

1256 unload birds. For heavier birds, it is strongly recommended to install slides, conveyors

1257 and other devices so birds do not experience hard falls onto the conveyor. In order to

1258 prevent smashed heads in drawer systems, when closing the drawer on the farm, there

1259 should be a 1.5 inch gap between the top of the plastic drawer and the metal rack.

1260 The live bird shackling area requires constant supervision to prevent rough handling

1261 and bird abuse.

1262 Hanging inverted on conventional shackles is stressful to chickens (Kannen et al.,

1263 1997; Benadova et al., 2007) however, new designs for poultry shackling systems may

1264 help reduce stress. In one design, the breasts of the birds are supported by a horizontal

1265 moving conveyor (Lines et al., 2011). In another new commercially available system, the

1266 body of the shackled bird is supported by a plastic devise attached to the shackle.

1267

1268 Step 3—Electric Stunning

1269 The birds, which can be chickens, turkeys or other poultry, are moved to the water

1270 bath stunner while they are inverted and hanging by their feet on the shackle line. The

1271 bird’s head is immersed in the water and an electric current is passed from the water to

1272 the leg shackle.

1273 Detection of Problems during Electric Stunning of Poultry

1274 One of the most common problems is birds missing the stunner water bath because

1275 small “runt” chickens are mixed in with market ready chickens. These birds are too short

1276 to be immersed in the water bath. Another problem is rapid return to consciousness after

1277 stunning. This is caused by setting the stunner amperage too low. Plant managers

1278 sometimes do this to prevent meat damage. Pre-shocks as birds are entering the stunner

1279 may happen if wing tips reach the water bath before the birds head is immersed. These

1280 shocks do not produce unconsciousness because they occur before the birds are fully

1281 immersed.

1282 Corrective Action for Problems with Electric Stunning

1283 The height of the water bath stunner must be adjusted so that the birds cannot pull

1284 themselves up and avoid the stunner. It is also essential to avoid distractions such as

1285 people walking under the birds or doors opening and closing near the stunner entrance.

1286 These distractions can cause birds to pull up. The rail should run smoothly because a

1287 bumpy ride may cause birds to flap and avoid the stunner. Pre-shocks can be reduced

1288 with a well-designed entrance ramp on the stunner (cut out) adjusting the water level.

1289 References

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1483 Techniques

1484 Atmospheric Methods

1485 Controlled Atmosphere

1486 Controlled atmosphere stunning/killing methods (CAS), also called modified

1487 atmosphere stunning (MAS) or killing (MAK), produce unconsciousness, and can

1488 eventually lead to death, by one of two basic methods: 1) by displacing air and the

1489 oxygen it contains to produce O2 levels less than 2% (e.g. hypoxia/anoxia using inert

1490 gases, such as N2 or Ar, or low atmospheric pressure stunning), or 2) by rapidly inducing

1491 decreased intracellular pH and cellular function through acute hypercapnea (CO2; e.g.

1492 carbon dioxide used either alone or together with inert gases and/or supplemental oxygen

1493 to produce hypercapneic anoxia, hypercapneic hypoxia, and hypercapneic

1494 hyperoxygenation). Sequential combinations of the two methods, also called “two step”

1495 or “multi-phase” processes, may use one gas or a mixture of gases to induce

1496 unconsciousness prior to exposure to a different gas mixture or higher gas concentration.

1497 Low atmospheric pressure stunning (LAPS) is discussed in a separate section.

1498 Whether a CAS method is classified as stunning or killing depends on the amount

1499 of time the animal remains in the modified atmosphere. Killing methods eliminate the

1500 concern that animals may regain consciousness prior to exsanguination. In either case,

1501 animals are not lifted or shackled until unconscious, such that pain, stress, and fear

1502 associated with handling are minimized. In addition to reducing live animal handling,

1503 CAS may facilitate the ability to process a greater numbers of animals (Nowak et al.,

1504 2007). As with all inhaled or atmospheric methods, unconsciousness is not immediate

1505 and any perceived distress and discomfort by animals will vary depending on the species,

1506 process, and gases used.

1507 There is controversy in the scientific community as to the optimum CAS gas

1508 mixture and conditions of application for humane slaughter. Distress during

1509 administration of CO2 and the inert gases N2 and Ar has been evaluated using both

1510 behavioral assessment and aversion testing and has been reviewed in the context of

1511 euthanasia (AVMA, 2013). It is important to realize that aversion is a measure of

1512 preference, and that while aversion does not necessarily imply that the experience is

1513 painful, forcing animals into aversive situations creates stress. The conditions of exposure

1514 used for aversion studies, however, may differ from those used for stunning or killing. In

1515 addition, agents identified as being less aversive (e.g., argon [Ar] or nitrogen [N2] gas

1516 mixtures) can still produce overt signs of behavioral distress (e.g., open mouth breathing)

1517 for extended time periods prior to loss of consciousness under certain conditions of

1518 administration (e.g., gradual displacement; Webster and Collett, 2012).

1519 A distinction must be made between immersion, where animals are placed

1520 directly into a high concentration of a gas or vapor within a container, and commercial

1521 CAS processes as employed for the stunning of poultry and hogs. Unlike immersion, in a

1522 commercial process animals experience their introduction into CAS atmospheres

1523 gradually, either through transport at a controlled rate into a contained stunning

1524 atmosphere gradient, or through controlled introduction of stunning gases into an

1525 enclosed space. The transport or introduction rate may be slow or relatively quick,

1526 depending on the process, gases used, and the specific species. Further, denser-than-air

1527 CAS gases including CO2 layer into gradients within an enclosed space (Dalmau et al.,

1528 2010a). Thus, animals are not immediately exposed to stunning conditions known to be

1529 aversive or painful.

1530 Hypoxia produced by inert gases such as N2 and Ar appears to cause little or no

1531 aversion in turkeys (Raj, 1996) or chickens (Webster and Fletcher, 2004), where birds

1532 freely entered a chamber containing less than 2% O2 and greater than 90% Ar. When Ar

1533 was used to euthanatize chickens, exposure to a chamber prefilled with Ar, with an O2

1534 concentration of less than 2%, led to EEG changes and collapse in 9 to 12 seconds. Birds

1535 removed from the chamber at 15 to 17 seconds failed to respond to comb pinching.

1536 Continued exposure led to convulsions at 20 to 24 seconds. Somatosensory-evoked

1537 potentials (SEP) were lost at 24 to 34 seconds, and the EEG became isoelectric at 57 to

1538 66 seconds (Raj et al., 1991). With turkeys, immersion in 90% Ar with 2% residual O2

1539 led to EEG suppression in 41 seconds, loss of SEP in 44 seconds, and isoelectric EEG in

1540 101 seconds, leading the authors to conclude that exposure times greater than three

1541 minutes were necessary to kill all birds (Raj and Gregory, 1993). Gerritzen et al. (2000)

1542 also reported that chickens did not avoid chambers containing less than 2% O2; birds

1543 gradually became unconscious without showing signs of distress.

1544 Chickens (McKeegan et al., 2006; Webster and Fletcher, 2001; Gerritzen et al.,

1545 2000; Lambooij et al., 1999) and turkeys (Raj, 1996) killed by hypoxia show less head

1546 shaking and open-beak breathing than birds exposed to CO2. Respiratory disruption,

1547 defined as open-bill breathing with prolonged inspiration or prolonged open bill gaping

1548 with apparent apnea or dyspnea, is less in anoxia-stunned birds compared with methods

1549 combining anoxia with CO2 (Coenan et al., 2009; Gerritzen et al., 2000). Mandibulation,

1550 the rapid open and closing of the beak, may occur with anoxic systems, but may occur

1551 less than in other systems (Abeyesinghe et al., 2007). However, broilers are noted to

1552 have more episodes of wing flapping when stunned with N2, either alone or combined

1553 with 30% CO2, than with a two-step process using 40% CO2, 30% O2, and 30% N2

1554 followed by 80% CO2 in air (Coenan et al., 2009). Failure to maintain less than 2% O2

1555 when using hypoxic/anoxic inert gas methods prolongs survival (Raj and Gregory, 1990;

1556 Raj and Whittington, 1995).

1557 In pigs, hypoxia produced by combining N2 and Ar appears to reduce, but not

1558 eliminate, aversive responses. Pigs chose to place their head in a hypoxic (less than 2%

1559 O2, 90% Ar) chamber containing a food reward, remained with their head in the chamber

1560 until they became ataxic, and freely returned to the chamber once they regained posture

1561 (Raj and Gregory, 1995). In contrast, exposure to 90% Ar, 70% N2/30% CO2, and 85%

1562 N2/15% CO2 all resulted in signs of aversion, defined by the authors as escape attempts

1563 and gasping; the proportion of pigs showing these behaviors was lowest with Ar (Dalmau

1564 et al., 2010a). Early removal from a hypoxic Ar or N2 stunning gas atmosphere results in

1565 rapid return to consciousness, such that exposure times greater than 7 minutes are needed

1566 to ensure killing with these gases (Raj, 1999).

1567 Inhalation of CO2 causes acute respiratory acidosis and produces a reversible

1568 anesthetic state by rapidly decreasing intracellular pH (Martoft et al., 2002). Both basal

1569 and evoked neural activities are depressed soon after inhalation of 100% CO2 (Martoft et

1570 al., 2002; Raj et al., 1997; Ring et al., 1988; Forslid, 1987). For pigs, exposure to 60 to

1571 90% CO2 causes unconsciousness in 14 to 30 seconds (Dalmau et al., 2010b; Martoft et

1572 al., 2002; Raj et al., 1997; Raj and Gregory, 1996) with unconsciousness occurring prior

1573 to onset of signs of excitation (Dalmau et al., 2010b; Forslid, 1987). For light Manchego

1574 lambs, exposure to 90% CO2 for 60 seconds results in 100% stun (Bornez et al., 2009),

1575 with observed levels of cortisol, epinephrine, and norepinephrine similar to electrically

1576 stunned animals (Linares et al., 2008). A large proportion of chickens and turkeys will

1577 enter a chamber containing moderate concentrations of CO2 (60%) to gain access to food

1578 or social contact (Webster and Fletcher, 2004; Gerritzen et al., 2000; Raj, 1996).

1579 Following incapacitation and prior to loss of consciousness, birds in these studies show

1580 behaviors such as open-beak breathing and head-shaking; these behaviors, however, may

1581 not be associated with distress because birds do not withdraw from CO2 when these

1582 behaviors occur (McKeegan et al., 2006). Unlike N2 and argon, which must be held

1583 within a very tight range of concentration to produce oxygen levels less than 2%, CO2

1584 can render animals unconscious over a wide range of concentrations, even when O2 is

1585 greater than 2% (Raj, 2008).

1586 Death via exposure to CO2 has been described for individual and small groups of

1587 birds (Franson, 1999; Webster and Collett, 2012). Carbon dioxide and its application to

1588 the humane slaughter of chickens, turkeys, and ducks has been studied extensively and

1589 has resulted in information about times to collapse, unconsciousness and death, loss of

1590 SEPs, and changes in EEG. Leghorn chicks seven days of age collapsed in 12 seconds

1591 after exposure to 97% CO2 (Blackshaw et al., 1988). Raj (1995) found that two minutes

1592 exposure to 90% CO2 was sufficient to kill day-old chicks exposed in batches. Broilers

1593 five weeks of age collapsed an average of 17 seconds after entering a tunnel filled with

1594 60% CO2 (Gerittzen et al., 2000). In a CAS system designed for small flock

1595 depopulation, LOP was observed in approximately 20 seconds for various ages of layers

1596 and broilers in a 50% CO2 atmosphere and approximately 30 seconds for turkeys in a

1597 40% atmosphere (Webster and Collett, 2012). In tests where it took eight seconds to

1598 achieve the target gas concentration, broilers and mature hens collapsed in 19-21 seconds

1599 at 65% CO2 and 25-28 seconds at 35% CO2 (Raj and Gregory, 1990). In a gradual-fill

1600 study, ducks and turkeys lost consciousness before 25% CO2 was reached and died after

1601 the concentration reached 45% (Gerritzen et al., 2006). At 49% CO2, EEG suppression,

1602 loss of SEP, and EEG silence occurred in 11, 26 and 76 seconds in chickens (Raj et al.,

1603 1992). In turkeys, EEG suppression took place in an average of 21 seconds at 49% CO2,

1604 but was reduced to 13 seconds at 86% CO2. In the same report, time to loss of SEP’s was

1605 not affected by gas concentration, averaging 20, 15, and 21 seconds, but time to EEG

1606 silence was concentration-dependent, i.e., 88, 67, and 42 seconds, for 49%, 65%, and

1607 86% CO2, respectively (Raj and Gregory, 1994).

1608 For humane slaughter of poultry, exposure to CO2 concentrations producing a

1609 gradual induction of unconsciousness reduces convulsions compared to anoxia with N2

1610 and Ar (Poole and Fletcher, 1995; Webster and Fletcher, 2001). Practical experience in

1611 commercial slaughter facilities indicates that a smooth gradual increase in CO2 from 0%

1612 to more than 50-55% reduces bird reactions prior to LOP; chickens require a more

1613 gradual increase in CO2 concentration over time than turkeys (Grandin, 2010). Carbon

1614 dioxide may invoke involuntary (unconscious) motor activity in birds, such as flapping of

1615 the wings or other terminal movements, which can damage tissues and be disconcerting

1616 for observers (Blackshaw et al., 1988). However wing flapping is less with CO2 than

1617 with N2 or Ar (Poole and Fletcher, 1995; Coenan et al., 2009). A two-step or multi-phase

1618 process combining inert gases and CO2 is used commercially for humane slaughter of

1619 poultry, where birds are exposed initially to 40% CO2, 30% O2, and 30% N2, followed by

1620 80% CO2 in air; the added O2 during the anesthetic induction phase has both welfare and

1621 carcass-quality advantages (McKeegan et al., 2007a, 2007b; Coenan et al., 2009). Thus,

1622 vocalization and non-purposeful movement observed after LORR/LOP with properly

1623 applied controlled atmospheric methods are not necessarily signs of conscious

1624 perception by the animal. While generalized seizures may be observed following

1625 effective CAS methods, these generally follow loss of consciousness; indeed, anesthesia,

1626 coma, and generalized seizures all represent a loss of consciousness where both arousal

1627 and awareness in humans is low or absent (Cavanna, 2011). Loss of consciousness should

1628 always precede loss of muscle movement.

1629 Genetics may play a role in pig CO2 response variability. Panic disorder in

1630 humans is genetically linked to enhanced sensitivity to CO2 (Battaglia et al., 2007). The

1631 fear network, comprising the hippocampus, the medial prefrontal cortex, the amygdala

1632 and its brainstem projections, appear to be abnormally sensitive to CO2 in these patients

1633 (Nardi et al., 2009). The genetic background of some pigs, especially excitable lines such

1634 as the Hampshire and German Landrace, has been associated with animals that react

1635 poorly to CO2 stunning, while calmer lines combining the Yorkshire or Dutch Landrace

1636 conformations show much milder reactions (Grandin 1994, 2010). Given a choice,

1637 Duroc and Large White pigs will tolerate 30% CO2 to gain access to a food reward, but

1638 will forego the reward to avoid exposure to 90% CO2, even after a 24 hour period of food

1639 deprivation (Raj and Gregory, 1996, 1995). A shock with an electric prod, however, is

1640 more aversive to Landrace X Large White pigs than inhaling 60% or 90% CO2, with pigs

1641 inhaling 60% CO2 willing to re-enter the crate containing CO2 (Jongman et al., 2000).

1642 Until further research is conducted, one can conclude that use of CO2 may be humane for

1643 certain genetic lines of pigs and stressful for others (Grandin, 2010).

1644 CAS Design

1645 The mechanical design of commercial CAS systems has been reviewed by

1646 Grandin (2010). In open CAS systems the entry point is open to the atmosphere with

1647 negligible concentrations of stunning gas present. Animals are moved on continuous

1648 conveyors through a tunnel or into a pit containing a heavier-than-air gas, such as CO2 or

1649 Ar. In a closed CAS system, batches of animals are placed inside a chamber and

1650 stunning gases are introduced to the specified concentration through a recirculating

1651 ventilation system that displaces oxygen by the stunning gases. As with other inhaled

1652 methods, changes in gas concentration within any enclosed space involve two physical

1653 processes: 1) wash-in of new gas (or wash-out of existing gas) and 2) the time constant

1654 required for that change to occur within the container for a known flow rate (Meyer and

1655 Morrow, 2005; Meyer, 2008). Although closed systems can potentially operate using any

1656 stunning gas, inert gases such as N2 work best in such systems because O2 levels less than

1657 2% can be achieved. This level of hypoxia is difficult to achieve in open CAS systems

1658 because N2 is less dense than air, and therefore, difficult to contain. Also, closed CAS

1659 systems use a greater volume of stunning gas than open systems because the stunning

1660 area must be evacuated prior to loading the next group of animals.

1661 Detection of Problems

1662 Some of the most common problems are CO2 concentration that is too low or

1663 insufficient dwell time in the chamber. These problems can result in either return to

1664 sensibility on the slaughter line or stressful anesthetic induction. Insufficient dwell time

1665 is most likely to occur in plants that have an undersized equipment. Many CO2 systems

1666 have automated powered gates to move animals into the chamber. There is a serious

1667 problem if the automated gates either knock animals over or drag them along the floor. If

1668 these gates cause more than 1% of the pigs to fall, that exceeds the industry voluntary

1669 guideline (Grandin, 2010). If powered gates drag animals, that is a violation of the

1670 HMSA. Another problem is overloaded gondolas where animals do not have room to

1671 stand without being on top of other animals. This is most likely to occur in equipment

1672 that does not have sufficient capacity.

1673 Corrective Action for Problems

1674 1. Maintain a CO2 concentration of over 80%. A 90% concentration at the

1675 bottom of the pit is strongly recommended.

1676 2. Increase dwell time if there are problems with return to sensibility.

1677 3. Undersized equipment that has insufficient capacity is often the cause of

1678 insufficient dwell time or handlers overloading the gondolas with animals.

1679 Either a larger piece of equipment or an additional unit will be required to

1680 increase system capacity.

1681 4. The pigs must have sufficient room in the gondolas to stand without being on

1682 top of each other.

1683 5. When automated gates are used to move pigs up to and into the chamber, they

1684 must be equipped with pressure limiting devices. This prevents the gates

1685 from knocking animals over or dragging them along the floor. Often

1686 powered gates work best when they are equipped with a push button or other

1687 control which allows the handlers to control forward movement of the gate.

1688 When the handler lets go of the control, the gate stops. An automated control

1689 works well to return the gate to its start position after it has moved the

1690 animals.

1691 6. Ventilation problems in the plant building can sometimes cause CO2 to be

1692 sucked out of the chamber. Commercial CO2 equipment holds CO2 in a pit

1693 that is not sealed and sometimes air pressure changes in the plant building can

1694 cause sensible pigs to emerge from the chamber. Some of the factors that can

1695 suddenly lower CO2 concentration are either turning off or turning on large

1696 ventilation fans in the plant building, wind blowing around the plant building

1697 or leaving certain plant doors open. Careful observation will be required to

1698 correct this problem. It is often correctible and no equipment purchases are

1699 required.

1700 Conclusions

1701 For humane slaughter of poultry, initial exposure to lower CO2 concentrations

1702 produce a gradual induction of unconsciousness and reduce convulsions compared to

1703 anoxia with N2 and Ar. Carbon dioxide may invoke involuntary (unconscious) motor

1704 activity in birds, such as flapping of the wings or other terminal movements, which can

1705 damage tissues and be disconcerting for observers, however wing flapping is less with

1706 CO2 gas mixtures than with N2 or Ar. For humane slaughter of pigs, exposure to greater

1707 than 80% CO2 is recommended.

1708 Compared with electrical stunning methods, CAS for poultry epresent some

1709 animal welfare advantages because manual handling and shackling of live birds is

1710 eliminated. Some gas mixtures may cause escape behaviors, such as attempting to climb

1711 up the sides of the container or vigorous flapping in chickens before LOP. In addition,

1712 CAS can also eliminate welfare issues associated with tipping live birds from their

1713 transport cages prior to stunning, however this depends on the design and implementation

1714 of CAS at the processing plant. CAS for pigs and lambs may also improve animal welfare

1715 by reducing animal handling.

1716 Low Atmospheric Pressure

1717 Low atmospheric pressure stunning (LAPS) is a recently described method for

1718 stunning birds prior to humane slaughter. Unconsciousness due to hypoxia occurs

1719 following a controlled and gradual reduction of barometric pressure (Purswell et al.,

1720 2007; Vizzier-Thaxton et al., 2010). The European Union allows the use of a vacuum

1721 chamber for slaughter of farmed quail, partridge, and pheasant (Council Directive

1722 93/119/EC), and the method is currently undergoing commercial testing for broiler

1723 stunning in the US under a USDA office of New Technology Testing Approval. It is not

1724 currently known whether the technology can be adapted for humane slaughter or

1725 depopulation of mammalian species, such as pigs; however, the insidious effects of

1726 altitude hypoxia on human flight crew performance, including unconsciousness, are well

1727 documented (Hypoxia, 2012).

1728 LAPS is not rapid decompression, as currently deemed unacceptable by the 2007

1729 AVMA Report on Euthanasia, but rather it is negative atmospheric pressure applied

1730 gradually over time, typically over 1 minute in broilers which results in an acute hypoxic

1731 state not unlike being in an unpressurized airplane at higher altitudes. Maximum

1732 observed negative pressure during commercial broiler LAPS is 23.8 in Hg (604.5 mmHg;

1733 Meyer RE. Personal observation at OK Foods, Ft. Smith AR., March 8, 2012); this

1734 corresponds to an atmospheric pressure of 155.5 mmHg and an inspired PO2 of 32.7

1735 mmHg (assuming barometric pressure of 760 mmHg - 604.5 mmHg = 155.5mmHg x

1736 0.21 = 32.7 mmHg oxygen). Thus, LAPS PO2 at maximum negative pressure is

1737 equivalent to a 4% oxygen atmosphere at sea level (32.7 mmHg/760 mmHg). For

1738 comparison, the atmospheric pressure (PB) on top of Mt. Everest (elevation

1739 approximately 30,000 ft) is 225 mmHg and the PO2 is 47.3 mmHg; at 40,000 ft, PB is 141

1740 mm Hg and PO2 is 29.6 mm Hg.

1741 Rapid decompression can cause both pain and distress through expansion of gases

1742 present in enclosed spaces (Booth, 1978). In the case of birds, however, gases are

1743 unlikely to be trapped in the lungs or abdomen during LAPS, due to the unique anatomic

1744 structure of the avian respiratory system and are thus unlikely to become a source of

1745 abdominal distention. Avian lungs are open at both ends, rigid, attached to the ribs, and

1746 do not change size during ventilation. Attached to the lungs are 9 air sacs that fill all

1747 spaces within the thoracic and abdominal cavities. Because birds lack a diaphragm, they

1748 move air in and out during sternal movement using the intercostal and abdominal

1749 muscles; air movement is simultaneous and continuous with no passive or relaxed period.

1750 Thus, it is unlikely significant amounts of gas can be trapped within the avian lungs or

1751 abdomen unless the trachea is blocked for some reason (Fedde, 1998). In contrast to

1752 reports of hemorrhagic lesions in the lungs, brain, and heart of animals undergoing rapid

1753 decompression (Van Liere, 1943), no such lesions were observed in birds undergoing

1754 LAPS (Vizzier-Thaxton et al., 2010). No pathologic evidence of ear damage has been

1755 noted in LAPS birds (Dr. Yvonne Vizzier-Thaxton, Personal Communication, Mar 8,

1756 2012), and corticosterone concentrations in LAPS-stunned broilers were nearly one half

1757 the levels observed in electrically-stunned birds (Vizzier-Thaxton et al., 2010).

1758 The LAPS target pressure for broilers is achieved within 1 minute from the start

1759 of the LAPS cycle and maintained for 4 minutes 40 seconds to assure recovery does not

1760 occur prior to exsanguination. Time to first coordinated animal movement was 58.7+/-

1761 3.02 seconds, with “light-headedness” (defined as time from first head movement to first

1762 wing flap) noted within 69.3 +/- 6.37 seconds, and LOP (an indicator of loss of

1763 consciousness) occurring within 64.9 +/- 6.09 seconds. Neither mandibulation nor deep

1764 open-bill breathing was observed in LAPS birds; bill breathing and mandibulation are

1765 commonly reported during CAS stunning with various gas mixtures (Coenen et al.,

1766 2009). Wing and leg paddling was infrequent, lasting 15.1 +/-1.12 seconds following

1767 LOP (Vizzier-Thaxton et al., 2010). Based on EEG studies, increasing slow (delta) wave

1768 activity consistent with a gradual loss of consciousness occurs within 10 seconds of the

1769 start of the LAPS cycle, peaking between 30-40 seconds and coincident with LOP and

1770 first brief movements (McKeegan, 2012). The same research group also determined that

1771 heart rate decreases over time during LAPS, implying minimal additional sympathetic

1772 nervous system stimulation.

1773 A significant advantage of LAPS over electrical stunning and live dump

1774 controlled atmospheric stunning is elimination of welfare issues associated with

1775 dumping live birds onto the conveyor line, and elimination of manually handling and

1776 shackling of live birds prior to electrical stunning. During commercial operation, birds

1777 undergoing LAPS are contained within palletized shipping cages on transport trucks in a

1778 holding area adjacent to the LAPS cylinders. Pallets are directly loaded into the LAPS

1779 cylinders using a fork lift. A computer in the control booth controls and displays the

1780 status of the individual LAPS units. LAPS operations are fully automated, such that once

1781 a cycle is initiated, the load operator cannot override or manually change the LAPS cycle.

1782 Each LAPS cylinder has a video camera mounted inside which can be viewed in real-

1783 time on a monitor in the control booth. Following the LAPS cycle, the palletized cages

1784 containing stunned birds are moved to the dumping station. After dumping, the birds are

1785 moved by conveyor belt to the shackling area prior to entry to the processing line. As

1786 previously noted, LAPS corticosterone levels are lower than with electrical stunning,

1787 likely due to elimination of live bird shackling.

1788 Conclusions

1789 LAPS produces a quiet transition to unconsciousness without escape behaviors

1790 and with minimal physical activity and wing flapping. Although wing flapping may be

1791 observed, it occurs following LOP, and therefore, consciousness. Compared with live-

1792 dump CAS methods and electrical stunning methods, LAPS may be better from an

1793 animal welfare standpoint due to elimination of welfare issues associated with dumping

1794 live birds onto the conveyor line, and elimination of manual handling and shackling of

1795 live birds prior to electrical stunning. LAPS may have cost-saving and environmental

1796 advantages over CAS in shipping cages due to elimination of the need for gases and

1797 associated greenhouse gas emissions.

1798 Physical Methods

1799 Concussive

1800 Penetrating Captive Bolt

1801 Penetrating captive bolts have been used for ruminants, horses, and swine. Its

1802 mode of action is concussion and trauma to the cerebral hemisphere and brainstem

1803 (Blackmore, 1985; Daly and Whittington, 1989; Gregory, 2007). Properly done captive

1804 bolt stunning will instantly abolish visual and SEPs from the brain (Daly, Gregory et al,

1805 1986 and Daly, Kallweit et al., 1988). This indicates that the animal’s brain is no longer

1806 able to respond to a visual or tactile stimulus, because it was instantly rendered

1807 unconscious. Adequate restraint is important to ensure proper placement of the captive

1808 bolt. A cerebral hemisphere and the brainstem must be sufficiently disrupted by the

1809 projectile to induce sudden loss of consciousness and subsequent death (Finnie, 1995;

1810 Lambooij, 1982). Appropriate placement of captive bolts for various species has been

1811 described (Clifford, 1984; Australian Vet Association, 1987; Daly and Whittington,

1812 1989; Woods et al., 2010; Lambooy and Spanjaard, 1981; Gregory et al., 2009). Signs of

1813 effective captive bolt penetration and death are immediate collapse and a several second

1814 period of tetanic spasm, followed by slow hind limb movements of increasing frequency

1815 (Blackmore, 1983; Finnie, 1995; Gregory, 2007). The corneal reflex must be absent and

1816 the eyes must open into a wide blank stare and not be rotated (Gregory, 2007; Gregory et

1817 al., 2007; Blackmore and Newhook, 1983).

1818 There are two types of penetrating captive bolts: a regular penetrating captive bolt

1819 and an air injection penetrating captive bolt. In both cases, the bolts penetrate the brain.

1820 In the air injection penetrating captive bolt, air under high pressure is injected through the

1821 bolt into the brain to increase the extent of tissue destruction. Powder-activated guns that

1822 use the traditional captive bolt are available in 9 mm, .22 caliber and .25 caliber (Woods

1823 et al., 2010). Captive bolt guns powered by compressed air (pneumatic) are also available

1824 for both the regular and air injection types. The air injection captive bolt must never be

1825 used on ruminants that will be used for food because of concerns about contamination of

1826 meat with specified risk materials (neurologic). Because the penetrating captive bolt is

1827 destructive, brain tissue may not be able to be examined for evidence of rabies infection

1828 or chronic wasting disease. All captive bolt guns require careful maintenance and

1829 cleaning after each day of use. Lack of maintenance is a major cause of captive bolt gun

1830 failure for both powder-activated and pneumatic captive bolt guns (Grandin, 1998).

1831 Cartridges for powder-activated captive bolt guns must be stored in a dry location

1832 because damp cartridges will reduce effectiveness (Grandin, 2002).

1833 General Recommendations

1834 Use of the penetrating captive bolt is acceptable for mature animals and it is the

1835 most common method used in beef slaughter plants. It is a practical method of humane

1836 slaughter for horses, ruminants, and swine. To ensure death, it is recommended that

1837 animals be immediately exsanguinated. Ruminants used for food should not be pithed to

1838 avoid contamination of the carcass with specified risk materials. Captive bolt guns used

1839 for larger species must have an extended bolt and the properly matched caliber and

1840 cartridge size. Use of a penetrating or non-penetrating captive bolt (controlled blunt force

1841 trauma) is a conditionally acceptable method of euthanasia for calves, lambs and kids.

1842 Controlled blunt force trauma differs from manually applied blunt force trauma because

1843 the captive bolt is able to deliver a uniform amount of force each time it is fired, and

1844 structural brain damage is more consistent. Studies using controlled blunt force trauma

1845 methods found that focal as well as diffuse injury caused by penetrating and non-

1846 penetrating captive bolt pistols was similar and sufficient for both to be considered

1847 effective for euthanasia of lambs (Finnie, 1995). Based on electrophysiologic evidence

1848 (Daly and Whittington, 1989), researchers determined that the primary determinant of

1849 effective stunning is impact of the bolt and not penetration of the bolt into brain tissues.

1850 In contrast, one report credits structural changes including focal damage adjacent to the

1851 wound track and damage to peripheral tissues of the cerebrum, cerebellum and brainstem

1852 as the predominant factors affecting effectiveness of the stun (Finnie, 2002).

1853 Detection of Problems

1854 Lack of maintenance is a major cause of captive bolt gun failure for both powder

1855 activated and pneumatic captive bolt guns (Grandin, 1998). Damp cartridges can result

1856 in underpowered shots that are less effective. Soft sounding shots were less effective

1857 (Gregory et al., 2007).

1858 A well-trained operator can easily render 95% or more of the animals unconscious

1859 with a single shot from a captive bolt gun (Grandin 2002, 2010). There is a definite

1860 problem if the effective first shot rate falls below 95% (Grandin, 2010). The very best

1861 plants have a 99% first shot efficacy (Grandin, 2005).

1862 Corrective Action for Problems

1863 1. Store cartridges for powder activated captive bolt guns in a dry location.

1864 Cartridges stored in a damp location were morelikely to produce ineffective “soft”

1865 shots (Grandin, 2002).

1866 2. Minimize movement of the animal’s head. This can be achieved with either a

1867 head holding device or behavioral methods such as changing lighting in the stun

1868 box. Head holders must be used with care, if poorly designed, they can increase

1869 cortisol levels and balking (Ewbank et al., 1992). In the center track conveyor

1870 system, the head will typically remains still without head restraint. This is due to

1871 having a long overhead solid top which prevents the animal from seeing out until

1872 its feet are off the entrance ramp and it is riding on the conveyor (Grandin, 2003).

1873 3. Head holders cannot be used on horses. Active head restraint, where a horse’s

1874 head is clamped by a mechanized device, should not be used. Passive restraint,

1875 such as a tray to prevent the horse from putting its head down, are acceptable.

1876 Passive devices restrain movement without clamping the head.

1877 4. A non-slip floor in the stun box is essential to prevent slipping. Slipping causes

1878 animals to become agitated. The stun box floor should be flat or have a slight

1879 slope. Steeply sloped or stepped floors hould not be used in stun boxes.

1880 5. Maintain the captive bolt gun per the instructions from the manufacturer. Captive

1881 bolt guns are precision machine tools and daily cleaning and maintenance is

1882 essential.

1883 6. Use a test stand to determine if the captive bolt has sufficient bolt velocity. The

1884 minimum bolt velocity is 55 m/s for steers and 70 m/s for bulls (Daly et al., 1988;

1885 Gregory, 2007). Most captive bolt manufacturers have test stands for their

1886 captive bolt guns.

1887 7. For pneumatic captive bolt guns, the air compressor that powers the gun must

1888 provide the air pressure and volume specified by the captive bolt manufacturer

1889 throughout the entire production shift. Air accumulation tanks or an undersized

1890 compressor will not provide sufficient power for the gun.

1891 8. Heavy pneumatic captive bolt guns must be hung on a well designed balancer so

1892 that the operator can easily position the gun without lifting its full weight. There

1893 are many balancer types and designs. Balancers must be well maintained; a

1894 partially broken balancer will make it difficult to position the pneumatic captive

1895 bolt, causing the operator to exert more effort to move the gun.

1896 9. Ergonomic design is especially important with pneumatic captive bolt guns

1897 because they are heavy and bulky. Small changes in handle location or the angle

1898 that the pneumatic gun hangs on the balancer can greatly improve ease of

1899 operation and require less effort to position.

1900 10. Switches and valves that operate gates or start and stop conveyors must be located

1901 in a convenient location. On a conveyor restrainer, the operator should be able to

1902 start and stop the conveyor without moving from the normal position for stunning.

1903 11. All the valves and switches for operating conveyors and gates must be kept in

1904 good repair. Partially broken hydraulic or pneumatic valves often require

1905 excessive effort to operate.

1906 12. In large plants that use cartridge fired captive bolt guns, more than one gun should

1907 be available to allow for gun rotation. Cartridge fired captive bolts are less

1908 effective when they get too hot. Rotating the guns and allowing hot guns to cool

1909 will prolong their useful life.

1910 13. Orientation toward the foramen magnum is critical in calves, lambs and kids

1911 because the head is often rotated during restraint and a direction perpendicular to

1912 the skull may be too rostral, resulting in penetration of the frontal sinus.

1913 Non-penetrating Captive Bolt Guns

1914 The non-penetrating captive bolt gun has either a wide mushroom-shaped head or

1915 a flat head that does not penetrate the brain of large mammals, such as adult cattle,

1916 slaughter-weight pigs, sows and adult sheep. In general, regular non-penetrating captive

1917 bolt guns only stun animals. Correct positioning is critical for an effective stun of an

1918 adult cow. When a non-penetrating captive bolt gun is used, there is little margin for

1919 error. The stun to stick interval must not exceed 60 seconds. To be effective on cows and

1920 steers, the shot must be more accurately positioned compared to penetrating captive bolt.

1921 Non-penetrating captive bolts are not effective for stunning bulls, adult swine, or cattle

1922 with long hair.

1923 Detection of Problems

1924 See “Detection of Problems-Penetrating Captive Bolt Guns”. Be aware that the

1925 non-penetrating captive bolt has a much smaller margin of error on aim.

1926 Corrective Action for Problems

1927 See “Detection of Problems-Penetrating Captive Bolt Guns”.

1928 Gunshot

1929 A properly placed gunshot can cause immediate unconsciousness. Under some

1930 conditions, a gunshot may be the only practical method of rendering animals with

1931 extremely heavy skulls unconscious, such as bulls or buffalo.

1932 Shooting should only be performed by highly skilled personnel trained in the use

1933 of firearms and only in jurisdictions that allow for legal firearm use. The safety of

1934 personnel, the public, and other animals that are nearby should be considered. For safety,

1935 a fully closed box that will contain a ricocheting bullet is strongly recommended.

1936 In applying gunshot to the head for the purposes of slaughter for captive animals,

1937 the firearm should be aimed so that the projectile enters the brain, causing instant loss of

1938 consciousness (OIE, 2011; AVA, 1997; Finnie, 1994; Longair et al., 1991; UFAW, 1988;

1939 Carding, 1977). This must take into account differences in brain position and skull

1940 conformation between species, as well as the energy requirement for skull bone and sinus

1941 penetration (Finnie, 1994; Blackmore, 1985). Accurate targeting for a gunshot to the head

1942 in various species has been described (Blackmore, 1995; Finnie, 1994; Longair et al.,

1943 1991). The appropriate firearm should be selected for the situation, with the goal being

1944 penetration and destruction of brain tissue without emergence from the contralateral side

1945 of the head (Woods et al., 2010; Finnie, 1997).

1946 1947

1948 Basic principles of firearms

1949 To determine whether a firearm or type of ammunition is appropriate for

1950 slaughtering animals some basic principles must be understood. The kinetic energy of an

1951 object increases as the speed and weight or mass of the object increases. In reference to

1952 firearms, the bullet’s kinetic energy (muzzle energy) is the energy of a bullet as it leaves

1953 the end of the barrel when the firearm is discharged. Muzzle energy is frequently used as

1954 an indicator of a bullet’s destructive potential. The heavier the bullet and the greater its

1955 velocity, the higher its muzzle energy and capacity for destruction of objects in its path.

1956 Muzzle energy (E) can be expressed as the mass of the bullet (M) times its

1957 velocity (V) squared, divided by 2 (Nelson, 2011). However, to accommodate units of

1958 measure commonly used in the United States for civilian firearms, energy (E) is

1959 expressed in foot pounds. This is calculated by multiplication of the bullet’s weight (W)

1960 times its velocity in feet per second (V) squared, divided by 450450. The International

1961 System of Units expresses muzzle energy in joules after the English physicist James

1962 Prescott Joule (1818–1889).

1963 Ballistics data for various types of firearms are provided in Tables 1, 2 and 3. The

1964 muzzle energy of commercially available ammunition varies greatly. For example, the

1965 difference in muzzle energy generated from a .357 magnum handgun loaded with a 180

1966 grain compared with a 110 grain bullet may differ by as much as 180 foot-pounds

1967 (Nelson, 2011). Velocity has an even greater impact on bullet energy than bullet mass.

1968 Selection of an appropriate bullet and firearm is critical to good performance when

1969 conducting euthanasia procedures. Lighter weight, higher velocity bullets can have high

1970 muzzle energy, but decreased penetration, which can be an issue when penetrating thick

1971 bones.

Table 1 – Muzzle energies for selected .22 caliber firearms and cartridges as listed by Remington in the rimfire ballistics table found in The Sight 10/22 at http://www.ruger1022.com/docs/22lrballistics.htm, accessed August 24, 2011.)

Firearm/Cartridge (bullet weight in Muzzle Energy in Joules grains) Foot Pounds CB Cap - .22 Short (29 gr) 34 46 Std Vel (Target) .22 LR (40 gr) 117 159 Gold Bullet Solid .22 LR (40 gr) 140 190 .22 Winchester Mag JHP (40 gr) 324 439

Table 2 —Average muzzle energies for common handguns (from USDA, 2004, National Animal Health Emergency Management System Guidelines, USDA, Washington, DC, at www.dem.ri.gov/topics/erp/nahems_euthanasia.pdf (as accessed 8-27-09) and cited by Woods et al., in Improving Animal Welfare, A Practical Approach, edited by Grandin, 2010, p.194-195). 1972 Firearm/Cartridge Muzzle Energy in Joules Foot Pounds .40 Smith and Wesson 408 553 .45 Automatic Colt Pistol 411 557 .357 Magnum 557 755 .41 Remington Magnum 607 823 10 mm Automatic 649 880 .44 Remington Magnum 729 988 1973 1974 Table 3 —Average muzzle energies for common rifles (adapted from USDA, 2004, 1975 National Animal Health Emergency Management System Guidelines, USDA, 1976 Washington, DC, at www.dem.ri.gov/topics/erp/nahems_euthanasia.pdf (as accessed 8- 1977 27-09) and cited by Woods et al., in Improving Animal Welfare, A Practical Approach, 1978 edited by Grandin, 2010, p.194-195). 1979 Muzzle Energy in Muzzle energy at 300 Firearm/Cartridge Foot Pounds (Joules) yards (274 meters) Joules in parentheses .223 Remington 1296 (1757) 574 (778) 30-30 Winchester 1902 (2579) 651 (883) .308 2648 (3590) 1193 (1617) 30-06 Springfield 2841 (3852) 1455 (1973) 1980

1981 Whereas most slaughter using firearms is conducted at close range, calculations of

1982 muzzle energy are useful for determining which firearms are appropriate for slaughter of

1983 animals of varying sizes. As the bullet travels beyond the muzzle of the firearm its energy

1984 gradually begins to decrease. While this is not a concern for the use of firearms in close

1985 proximity to the animal, when attempting to shoot an animal from a distance, to ensure

1986 accuracy and that an acceptable level of muzzle energy is achieved, a high-powered rifle

1987 may be the better choice for rendering an animal unconscious. In all cases, the most

1988 important factors in ensuring successful shot are the experience and skill of the shooter.

1989 Muzzle energy requirements

1990 Muzzle energy required to render animals up to 400 lb (180 kg) unconscious is a

1991 minimum of 300 ft-lb (407 joules). For animals larger than 400 lb (180 kg) firearms

1992 capable of yielding muzzle energies of 1000 ft-lb (1356 joules) are required for

1993 satisfactory results (Woods et al., 2010). Using this information to evaluate the options in

1994 Table 1 indicates that the CB Cap .22 Short, Std. Vel. (Target) .22 LR and the Gold

1995 Bullet Solid .22 LR would not be appropriate choices. Only the .22 Winchester Magnum

1996 JHP (jacketed hollow point) would have sufficient muzzle energy for consistent results

1997 with animals up to 400 lb (180 kg). These recommendations are corroborated by those of

1998 a Canadian study where .22 LR standard velocity and .22 LR high velocity bullets failed

1999 to yield adequate penetration of the skull (Baker and Scrimgeour, 1995). According to

2000 Table 2, all handguns listed would be considered to have sufficient muzzle energy for

2001 smaller animals (400 lb or less), but only rifles as listed in Table 3 would be sufficient for

2002 shooting of animals larger than 400 lb.

2003 Some would argue that the muzzle energies recommended above are well beyond

2004 what is necessary to achieve satisfactory results. Anecdotal comment suggests that the .22

2005 LR is frequently used to shoot livestock with varying degrees of success. There is little

2006 doubt that success or failure is partially related to firearm and bullet characteristics, but

2007 probably more so to selection of the ideal anatomical site (i.e., a site more likely to affect

2008 the brain stem) for conducting the procedure. The Humane Slaughter Association lists

2009 multiple firearms for humane slaughter of livestock including shotguns (12, 16, 20, 28

2010 and .410 gauges), handguns (.32 to .45 caliber) and rifles (.22, .243, .270, and .308). In

2011 general, when comparing handguns to rifles the longer the barrel the higher the muzzle

2012 velocity. Therefore, if a .22 is used for humane slaughter it is best fired from a rifle. The

2013 .22 should never be used on aged bulls, boars or rams (Humane Slaughter Association,

2014 1999).

2015 To improve safety and reduce dangerous ricochet of bullets that either pass

2016 through the animal’s head or miss the animal, many plant managers prefer the .22 long

2017 rifle. The high powered firearms on Table 3 are reserved for the animals with the

2018 heaviest, thickest skulls such as mature bovine bulls, bison bulls and large mature boars.

2019 The firearms listed on Table 2 can be used successfully on animals with moderately thick

2020 skulls. A .357 magnum pistol is effective on young fed bison. The .22 long rifle is

2021 effective for cows, steers, horses, market weight pigs (<275 lbs) and lambs. Some people

2022 prefer to use a pistol because it can be held closer to the head and many people find it

2023 easier to aim. Pistols must be larger than a .22. Practical experience has shown a

2024 carefully aimed .32 pistol works well on horses and market weight pigs.

2025 There are two main differences between use of a firearm in a slaughter plant and

2026 its use for on-farm euthanasia. In a slaughter plant, gunshot is followed by

2027 exsanguination so it is not the sole agent used to cause death. Another difference is an

2028 animal in a slaughter plant is shot at a close range of 1 ft. (0.3 m) to 2 ft. (0.6 m). When

2029 slaughter is done in less controlled situations out on the farm, a firearm larger than a .22

2030 long rifle is recommended. It is essential to aim the shot correctly so that the brain is

2031 penetrated. If an animal is injured and is not rendered unconscious with a single shot, it

2032 is sometimes much more difficult to kill thereafter. The nervous system may go into a

2033 state of arousal and multiple shots may fail. In one very bad case, a yak was shot ten

2034 times with a .38 firearm and a high powered .223 rifle was required to finally render it

2035 unconscious (USDA/FSIS, 2012).

2036 Bullet selection

2037 Bullet selection is quite possibly the most important consideration for slaughter of

2038 livestock by gunshot. There are 3 basic types of bullets pertinent to this discussion: solid

2039 points, hollow points and full metal jacketed bullets. Solid point bullets are preferred for

2040 shooting livestock since they are designed for greater penetration of their targets. Under

2041 ideal conditions this type of bullet will also undergo moderate expansion to a “mushroom

2042 shape” that increases its destructive characteristics. Hollow-point bullets are designed

2043 with a hollowed-out tip which causes rapid expansion and fragmentation of the bullet on

2044 impact. The hollow point design allows maximum transfer of energy without risk of over

2045 penetration. Hollow points are less likely to richochet but if the free bullet hits a person

2046 they are more dangerous then other bullets. For applications such as slaughter plants

2047 where it may desirable to control or reduce the degree of bullet penetration, hollow-point

2048 bullets are preferred. However, for the purposes of humane slaughter of livestock the

2049 first requirement is that the bullet possesses sufficient energy to penetrate the skull and

2050 enter the underlying brain tissue. The concern with hollow point bullets is that since the

2051 majority of their energy is released on impact through fragmentation they may not have

2052 sufficient energy to traverse the skull. Hollow points would be safer in a slaughter plant,

2053 but they may need to be used with a larger firearm than solid points. The other extreme

2054 is represented by full metal jacket bullets which do not expand or fragment on impact

2055 with their targets. These bullets have a lead core with a thin metal jacket cover that

2056 completely covers (surrounds) the bullet. Full metal jacket bullets generally achieve

2057 maximum penetration which may have benefits for humane slaughter but also creates

2058 additional safety hazards for bystanders. Full metal jackets are not recommended in

2059 slaughter plants due to safety issues. Shotguns loaded with shot shells (number 4, 5, or 6

2060 or slugs) have sufficient energy to traverse the skull, but unlike the possibility of bullets

2061 from either a handgun or rifle rarely exit the skull. These are important considerations

2062 when selecting a firearm for humane slaughter. Probably the most important point to be

2063 made relative to the use of gunshot for humane slaughter is that scientific information on

2064 firearm and bullet selection is lacking. There is an urgent need for research for best

2065 animal welfare.

2066 Firearm Safety

2067 Firearm safety cannot be over-emphasized. Guns are inherently dangerous and

2068 must be handled with caution at all times. This needs to become the mindset in handling

2069 and use of firearms. Common recommendations include: 1) assume that all firearms are

2070 loaded, 2) always know where the muzzle is and never allow it to point in the direction of

2071 oneself or bystanders, 3) keep fingers away from the trigger and out of the trigger guard

2072 until ready to fire, 4) be sure of the target and what lies beyond it, and 5) always be sure

2073 that the gun is unloaded when not in use. For those desiring more information or training

2074 on proper use of firearms readers are advised to contact those offering local Hunter

2075 Safety programs. These programs offer training in firearm safety and also provide

2076 information on rules and regulations for firearm use.

2077 Firearms should never be held flush to an animal’s body. The pressure within the barrel

2078 when fired may cause the barrel of the gun to explode, placing the shooter and observers

2079 at great risk of injury. Ideally, the muzzle of the firearm should be held within 1 to 2 feet

2080 of the animal’s forehead and perpendicular to the skull with the intended path of the

2081 bullet roughly in the direction of the foramen magnum. This will reduce the potential for

2082 ricochet while directing the bullet toward the cerebrum, midbrain and medulla oblongata

2083 which will assure immediate loss of consciousness and rapid death.

2084 When other methods cannot be used, an accurately delivered gunshot is acceptable for

2085 humane slaughter (NPB, 2009; AABP, 1999; Longair et al., 1991). When an animal can

2086 be appropriately restrained, the penetrating captive bolt, preferably one designed for

2087 euthanasia, is preferred to a gunshot because it is safer for personnel. Prior to shooting,

2088 animals accustomed to the presence of humans should be treated in a calm and reassuring

2089 manner to minimize anxiety. In the case of wild animals, gunshots should be delivered

2090 with the least amount of prior human contact necessary.

2091 Detection of Problems

2092 A well trained shooter can render 95% or more of the animals insensible with a

2093 single shot. There is a definite problem if the first shot efficacy rate falls below 95%

2094 (Grandin, 2012a). Safety is a major concern with firearms with a free bullet when they

2095 are used in a slaughter plant. Use of a firearm that is not sufficiently powerful is a

2096 common cause of failure of the first shot.

2097 Corrective Action for Problems

2098 1. Minimize movement of the animal’s head. Refer to recommendations for

2099 penetrating captive bolt gunsection.

2100 2. A non-slip floor in the stun box is essential to prevent slipping. Slipping causes

2101 animals to become agitated.

2102 3. The firearms must be taken apart and fully cleaned each day. The gun should be

2103 replaced when it becomes worn out. Some firearms are not designed for heavy

2104 continued shooting in a large slaughter plant. For each particular firearm, plant

2105 management needs to determine a schedule for replacement. A firearm should be

2106 completely destroyed before it is disposed of to keep it out of the hands of

2107 criminals. A very effective method is either crushing with a hydraulic press, or

2108 sledge hammer. For safety, the firearm MUST BE UNLOADED before it is

2109 crushed.

2110 4. Switch and valves – refer to captive bolt gun section.

2111 5. Two people should be used to move and shoot fractious or otherwise difficult to

2112 handle animals such as bison, and flightly animals such as horses or deer. One

2113 person moves the animal into the killbox or restrainer and the other shoots the

2114 animal. This makes it possible for the animal to be shot before it has an

2115 opportunity to become agitated.

2116 6. If the first shot fails to render instantaneous unconsciousness, the animal should

2117 be immediately shot again with a larger caliber firearm. This will help prevent

2118 the problem of an animal becoming severely agitated and multiple shots may be

2119 required to render it unconscious.

2120 Anatomic landmarks for use of the penetrating captive bolt and gunshot—In bovines, 2121 the point of entry of the projectile should be at the intersection of two imaginary lines, 2122 each drawn from the outside corner of the eye to the center of the base of the opposite 2123 horn (Figure 1, OIE, 2010). Firearms should be positioned so that the muzzle is 2124 perpendicular to the skull to avoid ricochet. 2125

2126 2127 2128 Figure 1—Anatomic site for gunshot or placement of a captive bolt and desired path of 2129 the projectile in bovids (Shearer, 2011) 2130 2131 Anatomic landmarks for captive bolts and gunshot—The location for placement of a 2132 captive bolt for entry of a free bullet for euthanasia of sheep and goats is illustrated 2133 below. The optimal position for hornless sheep and goats is the top of the head on the 2134 midline (OIE, 2010). An alternate site is the frontal region (OIE, 2010). For heavily 2135 horned sheep and goats, the optimal site is behind the poll aiming toward the angle of the 2136 jaw (OIE, 2010). 2137

2138

2139

2140 2141 2142 Figure 2—Anatomic sites for gunshot or placement of captive bolts and desired path of 2143 the projectile in sheep and goats. 2144 2145 2146

2147 2148 2149 Figure 3. Anatomic sites for gunshot and penetrating captive bolt application in swine. 2150 Using a face-on approach (A) the ideal target is half an inch above eye level, on the 2151 midline of the forehead and aiming toward the tail of the pig. There is also a temporal 2152 site (B) and a caudal site (C) aiming from behind the ear so that the projectile enters the 2153 skull from behind the ear and travels toward the opposite eye. 2154 2155 2156 Electrical

2157 Electrical stunning for humane slaughter causes immediate loss of consciousness

2158 (Croft 1952; Lambooij 1982). Alternating current has been used to euthanize dogs,

2159 cattle, sheep, goats, swine, chickens, foxes, mink and fish (OIE, 2011; Gregory, 2008;

2160 Anil, 1991; Hatch, 1988; Gregory, 2007; Lambooy and Van Vorst, 1986; Eikelenboom,

2161 1983; Warrington, 1974; Carding, 1977; Roberts, 1954; Loftsgard et al., 1972; Croft,

2162 1956). When done correctly, electrical stunning produces grand mal seizures or tonic

2163 (rigid) action followed by clonic (paddling) action. These seizures occur prior to the

2164 electrical transmission of pain stimuli to the central nervous system so the procedure is

2165 not painful or distressful.

2166 To produce the grand mal seizure, electrodes must be placed so that the current

2167 goes through the brain (Anil and McKinstry,1998a). For stunning, the current reaching

2168 the brain must be adequate to produce an epileptic seizure but less than that required for

2169 cardiac fibrillation leading to death (Bilgili, 1998). In poultry epileptic activity in the

2170 brain may require less current than that required for cardiac fibrillation and death (Bilgili,

2171 1998). In mammals reliable induction of an epileptic seizure may require a greater

2172 amount of current than that required for induction of cardiac arrest (Grandin, 2011). If

2173 killing is not performed quickly, then consciousness is regained (Fletcher, 1993).

2174 Principles

2175 Ohms Law involves current, potential difference (i.e., resistance) and frequency.

2176 Current, or what flows through a wire, is measured in terms of amps (A). Current is

2177 proportional to the potential difference across two points. Voltage (V) is a measure of

2178 that difference in electrical potential between two points in a wire. Resistance, which

2179 determines how much current will flow, is measured in terms of ohms. Power, or current

2180 multiplied by voltage, is measured in watts (W). Frequency, or the number of cycles per

2181 second, is measured in hertz (Hz).

2182 When electrical stunning is used for humane slaughter, appropriate electrical

2183 parameters must be used. These parameters vary with species and size. The effectiveness

2184 of electro-stunning, in general, increases with increasing current and decreasing

2185 frequency. A minimum of 1.25 amps is required for market weight pigs (Hoenderken,

2186 1983), 1.00 amp for sheep (Gregory, 2007), and 1.25 amps for cattle (Hoenderken, 1983).

2187 Amperage must be maintained for at least one second. Insufficient amperage can cause

2188 an animal to be paralyzed without losing insensibility (Grandin, 2004). Stunning market

2189 weight pigs with less than 1.25 amps should not be permitted (Grandin, 1994, 2004).

2190 Electronic equipment designed to provide constant amperage, which sets the amperage

2191 and allows voltage to vary according to animal resistance, may prevent amperage spiking

2192 (Grandin, 1985, 2004). Older voltage regulated electronic units allow changes in

2193 amperage (spiking) which may cause injury and blood spotting.

2194 The minimum current required to induce an epileptic response depends on the

2195 stunning frequency (Simmons, 1995). Unconsciousness is most effectively induced at a

2196 frequency of 50 cycles (50 Hz) (Warrington 1974; Anil and McKinstry, 1998b). Plant

2197 managers will often use higher frequencies to reduce damage to the meat caused by

2198 petechial hemorrhages (blood spotting). It is generally accepted that higher frequencies

2199 (800 Hz or greater) do not result in better stunning (Berghaus and McKinstry, 1998). In

2200 fact, the duration of clonic tonic seizures increases with higher stunning frequencies and

2201 incurs a delay in time to unconsciousness. Animals stunned using higher frequencies will

2202 regain sensibility more quickly (Anil and McKinstry, 1994). Frequencies of 2000 to

2203 3000 Hz failed to induce unconsciousness (Van der Wal, 1978; Grandin, 2004;

2204 Warrington, 1974). Grandin (2004) recommends that higher frequencies only be used

2205 when they are passed through at least two electrodes to the head. Frequenices of sine

2206 waves at 1592 Hz or square waves at 1642 Hz are effective in pigs but the period of

2207 unconsciousness will be shorter (Anil and McKinstrey, 1994). Eight hundred Hz applied

2208 to the head and 50 Hz applied to the body is also acceptable (Holleben and

2209 Wenzlawowicz, 1999).

2210 Proper electrical stunning must not be confused with electrical immobilization

2211 that paralyzes an animal without inducing unconsciousness (Lambooy 1985).

2212 Immobilization without unconsciousness is highly aversive and must not be used (Pascoe

2213 ,1986; Grandin et al., 1986). Electrocution induces death by cardiac fibrillation, which

2214 causes cerebral hypoxia (Loftsgard et al., 1972; Croft, 1956; Roberts, 1954). However,

2215 animals do not lose consciousness for 10 to 30 seconds or more after onset of cardiac

2216 fibrillation. It is imperative that animals be unconscious before being electrocuted.

2217 Unconsciousness can be induced by any method that is acceptable or acceptable with

2218 conditions, including passing a current through the brain (Grandin, 1994).

2219 Methods

2220 Three methods are used to do electrical stunning. They are the head only

2221 reversible method; the 1-Step ‘head to body cardiac arrest’ method; and the 2 Step ‘head

2222 only followed by a current applied to the body’ method which stops the heart (Grandin,

2223 2012b). The head only method does not cause cardiac arrest and will result in a return to

2224 consciousness in 15-30 seconds (Blackmore and Newhook 1982; Lambooij, 1982). In

2225 the head only method, animals should be bled within 15 seconds (Blackmore and

2226 Newhook, 1982). Tongs must be placed so that the current goes only through the head

2227 which can be accomplished by placing tongs either on both sides of the head or on the top

2228 and bottom of the head.

2229 The 1-Step method uses current applied from the ‘head to the body’ to induce

2230 cardiac arrest. Current is simultaneously passed through both the brain and the heart

2231 which induces cardiac fibrillation and immediate loss of consciousness (Lambooy, 1982;

2232 Grandin, 2012b). Wotton and Gregory (1986) suggest that the induction of cardiac arrest

2233 provides a major animal welfare advantage because it promotes the start of death. Use of

2234 the ‘head to body’ (or chest) method has been shown to be highly effective in inducing

100

2235 irreversible unconsciousness in over 98% of pigs evaluated (Verlarde et al., 1998). Pork

2236 plants using V shaped conveyor restrainers have achieved greater than 99% correct

2237 electrode placement when the 1-step head to back cardiac arrest method is used (Grandin,

2238 2001). Grandin (1985) recommends that when the 1-Step method is used that the first

2239 one second treatment should be at least 1.25 amps at 50-60 Hz. One electrode must be

2240 placed on the head and the other electrode can be placed on any part of the body (except

2241 for sensitive areas such as the eye, ear or rectum). The first electrode must not be placed

2242 on the neck or the back of the neck because the current will bypass the brain and cause

2243 instant pain.

2244 The 2-Step method uses the ‘head only’ method followed by a second application

2245 of the tongs to the chest. This method causes unconsciousness first and then death by

2246 cardiac arrest. Applying the second current by placing the electrode on the chest behind

2247 the foreleg has been reported to be effective (Vogel et al., 2010).

2248 Signs of Effective Stunning

2249 Unconsciousness occurs when electricity inhibits impulses from both the reticular

2250 activating and the somatosensory systems of the brain (Heath et al., 1994). Signs of

2251 effective seizure induction include extension of the legs, opisthotonus, and downward

2252 rotation of the eyeballs as well as epileptic seizures or the clonic tonic syndrome

2253 described above. The presence of an epileptic state has been considered to be a guarantee

2254 of an effective electrical stun (Hoenderken, 1978, 1983).

2255 On a more practical level, signs of effective stunning have been described

2256 (Grandin, 2010). Although the legs may move, it is the head that must be examined

2257 when the animal is hung on the rail after the rigid phase of the epileptic seizure stops. The

101

2258 head and neck should be limp and floppy and the tongue should hang out. Sheep heads

2259 may not hang directly straight down due to anatomical differences, but pig and cattle

2260 should hang straight down. If natural blinking occurs, the animals are not stunned.

2261 Nystagmus may occur in electrical stunning especially when frequencies greater than 50

2262 Hz are used. Rhythmic breathing must cease and vocalizations should not occur. Gasping

2263 is permissible after electric stunning but it must not be confused with rhythmic breathing

2264 where the animal’s ribs move in and out.

2265 General Recommendations

2266 Electrical stunning requires special skills and equipment that will ensure passage

2267 of sufficient current through the brain to induce loss of consciousness and tonic and

2268 clonic epileptic spasms. Unconsciousness must be induced before cardiac fibrillation or

2269 simultaneously with cardiac fibrillation. Cardiac fibrillation must never occur before the

2270 animal is rendered unconscious. Methods that apply electric current from head to tail,

2271 head to foot, or head to moistened metal plates on which the animal stands are

2272 unacceptable because they often bypass the brain. The 2-Step method should be used in

2273 situations where there may be questions about sufficient current to induce a grand mal

2274 seizure with tonic and clonic spasms. This approach enables observation of tonic and

2275 clonic spasms before a second current is applied to induce cardiac arrest.

2276 Electroimmobilization that paralyzes an animal without first inducing unconsciousness is

2277 extremely aversive and is unacceptable (Grandin et al., 1986; Pascoe, 1986). For both

2278 humane and safety reasons, the use of household electrical cords is not acceptable.

2279

2280

102

2281 Meat Quality

2282 The head only method has both animal welfare and meat quality issues (Velarde

2283 et al., 1998). Negative meat effects include decreased tenderness, increased drip-loss

2284 (water binding capacity; synersis leading to water puddling), and pale muscle color. Plant

2285 management may be tempted to lower the amperage and increase frequency to reduce

2286 blood splash (petechial hemorrhages) and broken backs. Stunner settings that reliably

2287 induce epileptic activity in the brain must be used.

2288 Cattle

2289 A 2-Step electrical stun method must be used with grown cattle (Grandin, 2004;

2290 Weaver and Wotton, 2008) due to the large size of this species. Current must be applied

2291 to the head to induce unconsciousness before a second current is applied to the body to

2292 induce cardiac arrest (Gregory, 1993). Because grown cattle are so large, the head must

2293 be properly restrained before affixing electrodes firmly to the head. A frequency of 50-60

2294 Hz should be used for the stun (Grandin, 2004) if head only stunning is used. A 3 second

2295 application of 1.15 amps at 50 cycles applied between the nose and the neck is effective

2296 to induce epileptiform activity in the brain (Wotton et al., 2000).

2297 Pigs and Small Ruminants

2298 In the interest of animal welfare, electrical stunning of sheep should be done with

2299 an amperage of at least 1.0 amps (160 volts) and in pigs, a minimum of 1.25 amps should

2300 be used for 100 kg animals (Gregory and Wotton, 1984; Hoenderken, 1983). In the U.S.,

2301 market pig weights are much heavier and more amperage may be required to reliabily

2302 induce unconsciousness in these animals. Pigs weighing 130 kilograms live weight

2303 requires 1.8 to 2.0 amps (Wenzlawowicz, 2009). More recent research has shown that

103

2304 amperage is the most important electrical parameter (Vegh et al., 2010), but the use of a

2305 single electrical parameter such as amperage is not sufficient to guarantee effective

2306 stunning (Vegh, 2009). Plant operators should also evaluate the animals for signs of a

2307 grand mal seizure using the methods described in Grandin (2010).

2308 The time between stunning and bleeding is critical when head only stunning is

2309 used. Animals should be bled within 15 seconds (Blackkmore and Newhook 1981;

2310 Lambooji, 1982). When cardiac arrest is induced, the animals should be bled within 60

2311 seconds. Most large commercial plants use head to body stunning where the current is

2312 passed simultaneously through both the brain and the heart (Grandin, 2012b, 2010). In

2313 small plants Grandin (2012b) has observed problems with animals returning to

2314 consciousness after head only stunning due to slow hoisting procedures. To prevent

2315 return to consciousness, a second current should be applied to the body immediately after

2316 initial head stunning to stop the heart (Vogel et al., 2011). Proper restraint is critical to

2317 allow the correct placement of the electrodes. Electrodes should be cleaned daily and

2318 properly maintained.

2319 Improper electric stunning of sheep and pigs can cause blood splash, pale muscle

2320 color or broken bones. These problems are a meat quality issue and not an animal

2321 welfare concern because passage of the current through the brain has already induced

2322 unconsciousness. The tongs or wand should be pressed firmly against the animal before

2323 the current is turned on. If the wand is energized before it is firmly applied, pigs will

2324 produce a short squeal but sheep will remain silent (Grandin 2010). This is a welfare

2325 concern because the animal would feel the shock. When the wand or tong is only partially

104

2326 applied, the animal does not receive the full amount of current (Gregory 2001). Electrical

2327 stunners work best when they are equipped with an automatic timer.

2328 Poultry

2329 Electrical stunning is the most universally accepted and used method for stunning

2330 prior to slaughter for poultry (Bilgili, 1998). The most widely used method for electro-

2331 stunning poultry is the electrical water bath stunning method which involves the

2332 immersion of the bird in an electrified water bath. Birds are shackled, hung upside down

2333 and passed through the water bath as quickly as possible. Each bird is immediately

2334 stunned for a period that lasts between 30 and 60 seconds (Hindle et al., 2010).

2335 Efficacy of the water bath system is influenced by the species, number and size of

2336 the birds passing through the water bath because with increasing size and number of birds

2337 in the bath at one time the resistance increases and because parallel paths of current arise

2338 with increasing numbers of birds. Variable resistance can result in insufficient current to

2339 produce immediate unconsciousness. Constant current stunners may alleviate this

2340 problem (Sparry et al., 1993).

2341 Smaller commercial facilities may use a hand held stunner for electrically

2342 stunning birds. When this method is used birds must be properly restrained and held.

2343 Electrodes must be properly constructed to ensure contact with skin through the birds

2344 feathering. Placing water on the head of the bird reduces resistance and enhances the

2345 electrocution process.

2346 Welfare issues for electrical stunning of poultry exist. Birds must be handled

2347 carefully as the shackling procedure may be distressful and/or painful (Kannan et al.,

2348 1997). If wing flapping occurs prior to the water bath stunner, then electric shock can

105

2349 occur without stunning (Raj, 1998). Breast bars can reduce the frequency of wing

2350 flapping. Shackles must be of the appropriate size for the species and specific birds. If

2351 hand held stunners are used, then appropriate placement of the electrodes between the

2352 ears and eyes is essential. Because of the variable resistance between species, flocks, and

2353 even individual birds, recommendations for optimal electric parameters for effective

2354 stunning in poultry are difficult to make. Improper settings can result in faster return to

2355 consciousness prior to throat cutting. Higher frequencies result in an increase in blood

2356 spotting (Hindle et al., 2010). Effective stuns require higher current to produce

2357 unconsciousness for at least 1 minute prior to neck cutting (Hindle et al., 2010).

2358 Contrary to the European model, electrical stunning in the U.S. is pulsed direct

2359 current with low-current (25-45 mA per bird; Bilgili, 1998), low voltage (10-25 V)

2360 (Bilgili, 1998; Craig and Fletcher, 1997; McNeal et al., 2003), and high-frequency (~ 500

2361 Hz) (Bilgili, 1998; Craig and Fletcher, 1997; McNeal et al., 2003). This style of system

2362 became possible with advances in electrical circuitry and a change to the length of the

2363 water bath cabinet to increase dwell time of the birds and decrease the total resistance in

2364 the water bath (Bilgili, 1998). In a survey of 329 U.S. poultry plants, 92.1% reported

2365 using electrical stunning and 77.4% of those plants use low voltage (10-25 Volts) and

2366 high frequency (500 Hz) systems (Heath et al., 1994).

2367 Efficacy of the stun in the U.S. plants has been determined by corneal and comb

2368 reflexes (Heath et al., 1994). Typically, a bird is considered stunned by plant personnel

2369 when it became unresponsive to the reflexes with eyes wide open, an arched neck and

2370 tucked wings (Heath et al., 1994). One study evaluated a two phase step-up stunner, with

2371 a first phase consisting of low voltage (12 and 15 Volts), high frequency (550 Hz) pulsed

106

2372 direct current for 10 seconds followed by a second phase sine wave alternating current of

2373 50 Hz at 40, 50 and 60 Volts for 5 seconds (Prinz et al., 2010). The best results of this

2374 stun set-up occurred in male birds at the highest voltage settings (phase one 15 Volts;

2375 phase two 60 Volts) (Prinz et al., 2010). Significant to these best results were only 22%

2376 of the birds had positive corneal reflexes, 18% of birds showed spontaneous blinking and

2377 wing flapping was seen in less than 10% of the birds (Prinz et al., 2010). However, this

2378 research group also concluded that 45% of the birds did not achieve an isoelectric EEG

2379 (Prinz et al., 2010). Contradicting this, another research group evaluating a similar two

2380 phase step-up stunner (phase one 23 V, 550 Hz direct current for 10 seconds; phase two

2381 15 V, 60 Hz alternating current for 5 seconds), found that the post-stun EEG to have a

2382 brief period of high amplitude spikes which progressively decreased in amplitude over

2383 time (Buhr et al., 2003). The group found the EEG recording of the brain activity to be

2384 very similar to what they seen with the European model of electrical stunning (Buhr et

2385 al., 2003).

2386 Detection of Problems

2387 Failure to cause immediate unconsciousness is highly stressful and may be

2388 painful. Humans experience pain when electro-convulsive shock therapy fails

2389 (Zivotofsky, 2011). Several causes of electrical stunning failure have been noted. The

2390 most common causes of return to consciousness after any type of electric stunning are

2391 wrong electrode placement and poor bleeding (Grandin, 2001, 2012b). Another cause of

2392 failure that has been noted in cattle and pigs is dehydration of the animal prior to stunning

2393 (Grandin, 2012b). And finally, poor equipment maintenance can also cause failures in

2394 the procedure.

107

2395 Another common cause of failure to induce unconsciousness is incorrect

2396 placement of the electrodes (Grandin, 2001). Electrodes must never be placed on

2397 eyeballs, ears or other sensitive areas of the body. Likewise, electrodes must not be

2398 placed on wet metal plates on which the animal stands. Experiments with dogs showed

2399 that electrode positions where the brain is bypassed do not cause instantaneous

2400 unconsciousness. When electricity passes only between the fore- and hind limbs or neck

2401 and feet, it causes the heart to fibrillate but does not induce sudden loss of consciousness

2402 (Roberts, 1954). The animal will be electrocuted, but will remain conscious until it dies

2403 from cardiac fibrillation.

2404 Four options are available for correct electrode placement for the head-only

2405 method, including on both sides of the head between the eye and ear, the base of the ear

2406 on both sides of the head, and diagonally below one ear and above the eye on the

2407 opposite side of the head. For cattle, neck to nose is effective (Gregory 1993; Wotton

2408 and Gregory, 2000). For the 1-Step (head-to-back) method, the head electrode may be

2409 placed on the forehead or immediately behind the ear. The head electrode should never

2410 be placed on the neck because the brain will be bypassed (Grandin, 2001). Diagonal

2411 movement of the electrical current through the body can be accomplished by placing the

2412 head electrode behind one ear and the body electrode on the opposite side. Another

2413 position that is effective is head to back (Lambooy and Spanjaard, 1982). When the 2-

2414 Step procedure is used, placement of the body electrode behind the forelimb is effective

2415 (Vogel et al., 2010). Electrodes consisting of a metal band or chain around the nose and a

2416 band or chain around the thorax appear to be effective for pigs weighing up to 125 kg

2417 (Denicourt et al., 2009).

108

2418 Grandin (2012b) states that energizing the electrodes prior to placement should

2419 not be done because pigs will squeal, most likely from pain. Zivotofsky and his

2420 colleagues (2011) have stated that electrical stunning in humans may be stressful and

2421 they cite problems with human electroconvulsive convulsive therapy (ECT). It is likely

2422 that some of the distressful experiences reported by patients may be due to poor electrode

2423 contact. However, when the electrode is energized after it is firmly applied, the pig will

2424 not squeal (Grandin, 2001). When the electrodes are applied to the temporal fossae of a

2425 sheep’s head, they can be stunned multiple times with no increase in either heart rate or

2426 glucose secreation (Leach et al., 1980). This indicates that the sheep does not remember

2427 being repeatedly shocked.

2428 Even when electrical methods that stop the heart are used, there are a few animals

2429 where cardiac arrest is not induced. This is the reason why good bleeding technique is

2430 essential (Grandin, 2001). The most common cause of return to sensibility after head

2431 only stunning is a stun to bleed interval of over 15 seconds.

2432 When electrical methods are used, the following signs of return to consciousness

2433 must be absent: rhythmic breathing, righting reflex, vocalization, natural eye blink

2434 (menace reflex), and tracking of a moving object (Vogel et al., 2011). There are definite

2435 problems with electric stunning if pigs squeal or cattle moo or bellow when the electrodes

2436 are applied (Grandin, 2010). Vocalization cannot be used in sheep because sheep often

2437 do not vocalize when they are in pain. A well trained operator should be able to place the

2438 electrodes in the correct position on 99% or more of the animals. There is a problem if

2439 more than 1% of the cattle or pigs vocalize during electrode application (Grandin, 2001,

2440 2012a).

109

2441 Proper equipment maintenance is essential. At a minimum, electrodes should be

2442 cleaned once daily and regularly maintained (Grandin, 2004). Old, worn or rusted

2443 equipment should be replaced on a regular schedule.

2444 Corrective Action for Problems

2445 1. Check to insure that the electric stunner is inducing a grand mal epileptic seizure.

2446 The tonic and clonic spasm is clearly visible after head only stunning. When a 1-

2447 Step head to body method is used, the seizure may be masked. Often a very weak

2448 tonic and clonic movement is still visible (Grandin, 2010). If electro-

2449 immobilization is used to keep the carcass still after stunning, it must be turned

2450 off because it will totally mask the tonic and clonic spasms.

2451 2. The electric stunner should be equipped with a meter so that amperage levels can

2452 be monitored.

2453 3. Monitor stunner operations for electrode placement and vocalization during

2454 electric stunner placement. Appropriate plant monitoring programs for evaluating

2455 the effectiveness of electrical stunning should be implemented.

2456 4. Wet pigs to insure good electrical contact. They should be wet but not dripping

2457 with water. Large amounts of water dripping off the animal may cause the

2458 current to pass over the surface of the pig instead of through the brain. For sheep,

2459 cattle and other animals with wool or hair, a small stream of water should be

2460 applied either through the electrode or right beside it to wet the application area.

2461 5. Make sure animals are not dehydrated. Dehydrated animals are more difficult to

2462 render unconscious with electricity.

110

2463 6. Use a bleeding knife and techniques that will produce a stream of blood at least

2464 2.5 cm wide in pigs. A copius blood stream helps prevent problems with return to

2465 consciousness (Grandin, 2001).

2466 7. When head only stunning is used, equipment should be designed so that the

2467 animals are bled within 15 seconds after stunning. Well designed commercial

2468 plants that perform religious slaughter with head only stunning have equipment

2469 that is capable of achieving this goal. The two main methods for achieving rapid

2470 bleeding are either high speed hoists or bleeding the animal on a table

2471 immediately after it is ejected from the stun box or restrainer.

2472 8. The electrodes must be kept clean. A wire brush should be used to clean the

2473 electrodes several times each day.

2474 9. Stunning tongs or wands should be ergonimcally designed to reduce operator

2475 fatigue.

2476 10. Rotate the operators to help prevent fatigue. Data collected from an electronically

2477 monitored stunning unit showed that after 3 hours, the operator was more likely to

2478 fail to firmly press the electrode against the animal. Firm contact is essential for

2479 an effective stun (Gregory, 2001).

2480 11. Both sides of V conveyor restrainer should run at the same speed. If one side runs

2481 faster than the other, the animals will become agitated.

2482 12. Use insulated restraint equipment. Plastic slats are recommended on V conveyor

2483 restrainers and there should be no exposed bolts. When single animal restrainers

2484 are used, they should be insulated with plastic meat cutting board.

111

2485 13. For operator safety, all electric stunners should be equipped with an isolation

2486 transformer or other device that will prevent electricity from flowing from a

2487 single electrode to ground. The electricity should only flow between the two

2488 electrodes. The metal frame of the restrainer and operator catwalk must be

2489 connected to a good ground.

2490 14. All electrical components such as the stunner switch, plugs, cords, and control

2491 box should be kept dry. The only part of the stunner that should be wetted is the

2492 electrodes. When the plant is cleaned, the stunning tongs/wand should be

2493 removed and stored in a dry location. The stunner control box should be either

2494 placed in a separate dry room or kept covered during plant wash down.

2495 15. Several types of restrainers (for head and body) can be employed for a variety of

2496 species. Cattle, for example, must have a properly designed head restraint. A

2497 head holding device is usually not required for pigs or sheep.

2498 16. Employee training is essential.

2499 Other Physical Methods

2500 Decapitation

2501 Decapitation is not commonly employed in the commercial slaughter of food

2502 animals, but is often used for on-the-farm slaughter, primarily of poultry and rabbits.

2503 (Mason et al., 2009) When properly employed, this technique can be quick and humane

2504 method of slaughter, but if done incorrectly it has the potential to induce pain and distress

2505 on the animals. This method may be found to be aesthetically displeasing to those

2506 performing or observing the technique.

112

2507 In poultry killed by decapitation, convulsions frequently occur immediately to

2508 several seconds following application of the technique. Postmortem convulsions were

2509 avoided when chickens were electrically stunned prior to decapitation (McNeal et al.,

2510 2003)

2511 In a survey of 329 poultry slaughter plants, decapitation without prior stunning

2512 was used for 2% of birds killed (Heath et al., 1994). Decapitation is also a method that is

2513 sometimes used for home slaughter of poultry (Mason et al., 2009). Early studies on the

2514 effects of decapitation on brain electrical activity in chickens, sheep and rats showed

2515 persistence of activity for up to 13-14 seconds following decapitation, resulting in the

2516 conclusion that the animals’ head remained conscious during this time and may have

2517 experienced pain (Mikeska and Klemm, 1975; Gregory and Wotton, 1990; Tidswell et

2518 al., 1987). However, many recent studies have shown that this activity does not infer the

2519 ability to perceive pain, and conclude that loss of consciousness occurs rapidly following

2520 decapitation (Cartner et al., 2007; Vanderwolf et al., 1988; Derr, 1991; Holson, 1992).

2521 The concern that the blow from the decapitating device might induce pain is mitigated by

2522 the fact that afferent sensory nerves for the head and neck enter the spinal cord at the

2523 level of the second cervical vertebrae in most species; therefore the severing of the spinal

2524 cord at or above that level would prevent sensory input from the tissue injury from

2525 reaching the brain (Holson, 1992).

2526 Operator competence is required to perform decapitation in a humane fashion.

2527 The operator must be familiar with the technique and able to accurately place the blade

2528 high on the neck, ideally at the level of the first vertebra. Blades used for decapitation

2529 must be maintained to be kept sharp and able to sever the entire head without need for

113

2530 more than one blow. Animals must be restrained to prevent them from moving away

2531 from the blade. For poultry, restraint in a bleeding cone will not only facilitate accurate

2532 aim, but will also minimize tissue trauma from post mortem convulsions. Electrically

2533 stunning a bird prior to decapitation reduces the occurrence of post mortem convulsions

2534 (McNeal et al., 2003).

2535 Cervical Dislocation

2536 Cervical dislocation is not commonly employed in the commercial slaughter of

2537 food animals, but is often used for on-the-farm slaughter, primarily of poultry and rabbits

2538 (Mota-Rojas et al., 2008). When properly employed, this technique can be a quick and

2539 humane method of slaughter, but if done incorrectly it has the potential to induce pain

2540 and distress in the animals. This method may be found to be aesthetically displeasing to

2541 those performing or observing the technique.

2542 In poultry killed by cervical dislocation, convulsions frequently occur

2543 immediately to several seconds following application of the technique. Convulsions

2544 occurred for a shorter period of time in turkeys killed with cervical dislocation than those

2545 killed with blunt trauma (Erasmus et al., 2010a).

2546 Cervical dislocation entails the separation of the skull from the spine through a

2547 combination of stretching and hyperextension of the neck. Death from cerebral

2548 dislocation is thought to be due to blood vessel stretching leading to reduced blood flow

2549 and cerebral ischemia (Erasmus et al., 2010a). In mice, cervical dislocation resulted in

2550 apparent unconsciousness within 5-10 seconds, while immediate cessation of corneal

2551 reflexes and respiration occurred in rabbits (Cartner et al,, 2007; Weisbrod et al., 1984).

2552 The effectiveness of cervical dislocation can vary depending on the size and species of

114

2553 animal. For larger poultry with greater muscle mass in the cervical region, manual

2554 cervical dislocation can be difficult to perform properly and consistently (Keller, 1982;

2555 Mota-Rojas et al., 2008). In market-weight turkeys, manual cervical dislocation and

2556 mechanical dislocation using the bovine burdizzo castrating forceps failed to result in

2557 rapid loss of brainstem reflexes and was determined to be potentially distressing to the

2558 birds (Erasmus et al., 2010b). In comparing the results of mammalian cervical

2559 dislocation with that of turkeys and chickens, the authors suggested that significant

2560 species differences exist in the effectiveness of cervical dislocation.

2561 Those performing cervical dislocation should be familiar with the technique

2562 through practice on dead animals before attempting cervical dislocation on live animals.

2563 For smaller poultry, neck stretching is applied by holding the bird by the legs, then

2564 grasping the head behind the skull with two fingers and quickly and firmly pulling the

2565 head down and against the knuckle of the first finger to stretch the neck and separate the

2566 vertebrae (Erasmus et al, 2010a). For larger poultry, mechanical cervical dislocation

2567 using a stainless steel tool (Commercial Cervical DislocatorTM) has been developed that

2568 allows for rapid and efficient cervical dislocation (Commercial Cervical Dislocator). The

2569 stainless steel tool is affixed to a wall or post, the animal’s head is slid down a notch, then

2570 the operator uses both hands to pull up and out, resulting in rapid cervical dislocation.

115

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2874 Simmons NJ. The use of high frequency currents for the electrical stunning of pigs. M.S. 2875 thesis, University of Bristol, Langford, UK. 1995.

2876 Sparrey JM, Kettlewell PF, Paice MER, and Whetlor WC. Development of a constant 2877 current stunner for poultry processing. J Eng Res . 1993;56: 267-274.

2878 Tidswell SJ, Blackmore DK, Newhook JC. Slaughter methods: electroencephalographic 2879 (EEG) studies on spinal cord section, decapitation and gross trauma of the brain in lambs. 2880 N Z Vet J. 1987; 35:46-49.

2881 Universities Federation for Animal Welfare. Humane killing of animals. 4th ed. South 2882 Mimms, Potters Bar, Hertfordshire, England: Universities Federation for Animal 2883 Welfare, 1988;16–22.

2884 Van der Wal PG. Chemical and physiological aspects of pig stunning in relation to meat 2885 quality: A review. Meat Sci 1978;2:19-30.

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2886 Vanderwolf CH, Buzak DP, Cain RK, et al. Neocortical and hippocampal electrical 2887 activity following decapitation in the rat. Brain Res 1988; 451:340–344.

2888 Van Liere EJ. Anoxia: It’s effect of the body. The Univ of Chicago Press, Chicago IL. 2889 1943.

2890 Vegh A. Technical parameters of head only electrical stunning of pigs – Verifying under 2891 commercial conditions. Proceedings of the International Soc. Anim. Hygiene, Vechta, 2892 Germany, 2009; pp. 419-422.

2893 Vegh, A., Abonji-Toth Z, and Rafer P. Verification of the technical parameters of head 2894 only electrical stunning of pigs under commercial conditions. Acta Veterinaria 2895 Hungarica 2010;58:147-156.

2896 Velarde A, Faucitano L, Gispert M, Oliver MA and Diestre A. A survey of the efficacy of 2897 electrical and carbon dioxide stunning on insensitivity in slaughter pigs. Proc Intern 2898 Congress Meat Sci and Techn (Barcelona, Spain) 1998;44: 1076-1077(Abstr).

2899 Vizzier-Thaxton Y, Christensen KD, Schilling MW, Buhr RJ, and Thaxton JP. A new 2900 humane method of stunning broilers using low atmospheric pressure. J Appl Poult Res 2901 2010; 19:341-348

2902 Vogel KD, Badtram G, Claus JR, Grandin T, Turpin S, Wekyer RE, and Voogd E. 2011. 2903 Head only followed by cardiac arrest electrical stunning as an effective alternative to 2904 head only electrical stunning in pigs. Meat Sci 89:1412-1418.

2905 Warrington PD. Electrical stunning: A review of literature. Vet Bulletin 1974;44:617-633.

2906 Weaver AJ and Wotton SB. The Jarvis beef stunner effects of a prototype chest electrode. 2907 Meat Sci 2008;81:51-56.

2908 Webster AB, Collett SR. A mobile modified-atmosphere killing system for small-flock 2909 depopulation. J Appl Poult Res 2012;21:131-144

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2912 Webster AB, Fletcher DL. Assessment of the aversion of hens to different gas 2913 atmospheres using an approach-avoidance test. Appl Anim Behav Sci 2004;88:275-287.

2914 Weisbrod KS, Dennis MD, Dong WK, et al. Physical methods of euthanasia for rabbits. 2915 Comp. Med. 1984;34:516–517.

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2918 Woods J, Shearer JK and Hill J. Reocmmended on-farm euthanasia methods, In: T. 2919 Grandin 2010. Improving Animal Welfare: A Practical Approach, CABI Publishing, 2920 Wallingford, Oxfordshire UK, 2010;p. 186-193.

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2921 Wotton SB and Gregory NG. Pig slaughtering procedures: Time to lose brain 2922 responsiveness after exsanguination or cardiac arrest. J Anim Sci 1986;73:381-386. 2923 2924 Wotton SB, Gregory NG, Whittington PE, and Parkman ID. Electrical stunning of cattle, 2925 Vet Rec. 2000;147:681-684. 2926 2927 Zivotofsky AZ and Strous RD. 2011. A perspective on the electrical stunning of animals: 2928 Are there lessons to be learned from human electro-convulsive therapy (ECT)? Meat Sci 2929 2012;90(4):956-61.

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2930 Unique Species Issues 2931 2932 Additional Considerations: Bovine

2933 Bulls

2934 Large bulls, water buffalos or American bison with very thick and heavy skulls

2935 create challenges for stunning with captive bolt. Some plants have solved this problem

2936 by electing to shoot all bulls twice or by switching to the use of a large caliber firearm.

2937 While the latter option has been found to be effective, use of a firearm within the

2938 confines of a packing plant creates serious safety concerns. The newer more powerful

2939 Jarvis pneumatic captive bolt gun has largely overcome these problems but because of its

2940 size and weight, it must be properly mounted or a balance for effective positioning over

2941 the proper anatomical site. This has caused some to consider use of the poll position

2942 rather than the frontal site. Studies indicate that the poll position can be effective if the

2943 appropriate captive bolt gun is used and when the muzzle is directed so that the

2944 discharged bolt will enter the brain (Gregory et al., 2009). However, use of the poll

2945 position for penetrating captive bolt stunning is prone to problems associated with

2946 operator error resulting in misdirection of the bolt (for example, into the spinal cord) and

2947 a failure to render animals unconsciousness due to a shallow depth of concussion (i.e.,

2948 failure of the bolt to sufficiently penetrate the skull) (Gregory et al., 2009).

2949 Cull Cows

2950 Culling is a management decision designed to remove animals with undesirable

2951 characteristics and/or poor performance. For example, when choosing which animals to

2952 cull cattlemen consider pregnancy status, performance of cow’s previous calves, age and

2953 teeth wear, udder health and teat conformation, structural soundness of feet and legs,

127

2954 evidence of health problems such as cancer eye, and the animal’s disposition. The

2955 primary reasons dairy cows are marketed for slaughter are failure to become pregnant,

2956 mastitis and lameness. From the packer’s standpoint the most desirable (or most

2957 profitable) cull cows are those that leave herds for failure to become pregnant, since these

2958 animals are usually in the best (fattest) body condition. Most of these animals, along with

2959 culled bulls, enter packing plants that process ground beef. Culling of cows needs to be

2960 done proactively to ensure that culled cows are suitable for transport to slaughter. This is

2961 important to ensure that the well-being of the cows is not compromised and is more likely

2962 to result in useable product. Cows should be culled before they become weak and

2963 debilitated.

2964 Successful stunning of cattle (i.e., cow rendered insensible between stunning and death

2965 by exsanguination) requires a penetrating captive bolt with sufficient bolt speed and

2966 power to penetrate the cow’s skull. It also requires accurate placement of the captive bolt

2967 device over the intended site. When stunning procedures are properly applied the

2968 likelihood of a return to sensibility is believed to be low. However, a Canadian study

2969 designed to assess the likelihood of a return to sensibility following penetrating captive

2970 bolt stunning suggests differently. Thirty-two cull dairy cows were assigned to either

2971 group A (20 cows), which received penetrating captive bolt stunning following by pithing

2972 (within 10 minutes of stunning), or group B consisting of 12 animals, which were stunned

2973 but not pithed. Researchers observed that none of the 20 animals in the captive bolt plus

2974 pithing group (Group A) regained consciousness, whereas five of 12 (42%) animals in

2975 Group B (animals that were not pithed) exhibited signs of a return to sensibility. Four

2976 animals were described as having clinical signs consistent with reversible stunning and

128

2977 one demonstrated signs consistent with consciousness 20 minutes after being stunned

2978 with the captive bolt (Appelt and Sperry, 2007). Because it is common practice to

2979 exsanguinate animals in the packing plant environment, there may be less likelihood that

2980 cows will return to consciousness. However, these results do confirm the need for an

2981 adjunctive step whether the objective is slaughter or euthanasia.

2982 Grandin reports that the best packing plants are able to achieve a successful stun on

2983 average 97-98% of the time (Grandin, 2005). In an earlier study by Grandin involving 21

2984 packing plants, 17 successfully rendered all cattle insensible before they were hoisted

2985 onto the bleeding rail, whereas four plants had cattle showing evidence of a return to

2986 sensibility that required re-stunning (Grandin, 2002). Of 692 bulls and cull cows eight

2987 (1.2%) returned to sensibility after stunning. Stunning failure was attributed to storage of

2988 stunner cartridges in damp locations, poor cleaning and maintenance of the captive bolt

2989 guns, dirty triggers which resulted in misfire of the captive bolt, an inexperienced captive

2990 bolt operator who shot cattle too high on the forehead and stunning of cattle with thick

2991 and heavy skulls (Grandin, 2002). A UK study found 1.7% of 628 of cull cows that were

2992 stunned poorly (Gregory, 2006).

2993 Non-Ambulatory Cattle

2994 The incidence of non-ambulatory animals based upon non-fed cattle reports from

2995 federally inspected plants during 1994 and 1999 was 1.1 to 1.5% for dairy cows and 0.7

2996 to 1.1% for beef cattle (Smith et al., 1994; Smith et al., 1999; Stull et al., 2007). During

2997 2001, of 7,382 non-ambulatory fed and non-fed cattle arriving at 19 packing plants in

2998 Canada, 90% were dairy cattle (Doonan et al., 2003). Furthermore, this study reported

2999 that less than 1% of the non-ambulatory cases developed during the transit process.

129

3000 Nearly all developed the non-ambulatory condition on the farm of origin. A survey of

3001 auction markets where slaughter buyers purchase cull cows indicated that 13.3% of the

3002 dairy cows and 3.9% of the beef cows were severely emaciated (Ahola et al., 2011).

3003 Severe emaciation and weakness is a factor which makes cows more likely to become

3004 non-ambulatory. There are a few medical reasons why the downer cow condition is more

3005 common in dairy cattle, but there is no good justification for the transportation of animals

3006 with a high probability of becoming recumbent. Producers must be vigilant in their

3007 efforts to avoid transporting animals unfit for travel.

3008 Cattle that are non-ambulatory for a period of more than 24 hours are commonly referred

3009 to as “downers”. Occurrence is highest in dairy cattle and often traced to metabolic

3010 disorders, injuries, and infectious or toxic disease conditions. Periparturient

3011 hypocalcemia (milk fever) and complications associated with calving are the most

3012 common predisposing causes of the downer cow condition. In fact, one study identified

3013 the 3 major causes of downer cow problems in dairy cattle as hypocalcemia 19%,

3014 calving-related injuries 22% and injuries from slipping and falling 15% (USUHA, 2006).

3015 The primary cause of the downer cow syndrome in beef cattle is calving paralysis (Cox,

3016 1981).

3017 Estimates are that about 5% of dairy cattle in the US have hypocalcemia annually. The

3018 majority of cases (75%) occur within 24 hours of calving, 12% of cases within 24 to 48

3019 hours of calving and only about 6% of cases at calving. (Current Vet Therapy, 2009)

3020 However, when hypocalcemia occurs prior to, or in association with, calving it can be an

3021 important contributor to dystocia and may result in calving paralysis and associated

3022 complications. Hypocalcemia is rare in beef cattle, but may occur in conditions where

130

3023 severe dietary mineral imbalances are present. The incidence of milk fever is low in

3024 sheep, but may approach incidence rates similar to dairy cattle in dairy goats with high

3025 milk yield (Current Vet Therapy, 2009).

3026 Calving paralysis is a common cause of recumbency in cattle. It is usually the

3027 consequence of attempts to deliver a large calf relative to the pelvic size of the cow.

3028 Paralysis results from damage to branches of the ischiadic (sciatic) and obturator nerves

3029 which are vulnerable to compression at calving by virtue of their position within the birth

3030 canal (Greenough, 1997).

3031 Traumatic injuries may be the primary cause of recumbency or they may occur as a

3032 secondary consequence of a cow that is down and struggling to rise. Examples of such

3033 lesions would include sacroiliac (hip) luxation, coxofemoral luxation (uni or bi-lateral),

3034 pelvic or other fractures and rupture of the gastrocnemius tendon. These injuries also

3035 occur as a consequence of slips and falls. Injuries of the upper leg and pelvis increased

3036 significantly in cows during the summer months in a southeastern dairy as a result of wet

3037 concrete flooring conditions (Shearer et al. 2006).

3038 Downer Cow Syndrome

3039 Cows recumbent for prolonged periods are also subject to peripheral nerve injury and

3040 muscle damage that can increase the odds of a permanent non-ambulatory state. Because

3041 of its sheer size and weight, a non-ambulatory cow develops tremendous pressure on

3042 tissues of the downed leg leading to decreased blood flow, hypoxia and pressure necrosis

3043 of muscle and peripheral nervous system tissues. Because of its anatomic location, injury

3044 to distal branches of the sciatic nerve is particularly common in recumbent cattle.

3045 Ischemic damage to heavy muscles of the rear legs result in varying degrees of paresis

131

3046 that complicate the possibilities of recovery in affected animals. The corollary to this

3047 condition in humans is “compartment syndrome” (Greenough, 1997).

3048 The threshold for induction of permanent recumbency (down and unable to rise) in dairy

3049 cattle seems to be as short as six hours. Of 84 periparturient cows down with

3050 hypocalcemia, 83 (98.8%) recovered when treatment was instituted within 6 hours after

3051 they became recumbent (Fenwick et al., 1986). Similarly, a survey of dairy producers

3052 indicated that non-ambulatory cattle that recovered and remained in the herd were down

3053 for less than six hours (USAHA, 2006). While good footing, attitude of the cow and

3054 body condition are fundamental to care for non-ambulatory animals, research from a UK

3055 study suggests that good nursing care may have the single greatest effect on improving

3056 the prognosis for non-ambulatory cattle (Chamberlain and Cripps, 1986).

3057 The Prevention of Non-Ambulatory Cattle and Downer Cow Syndrome

3058 Many of the conditions that predispose to non-ambulatory cattle occur around the time of

3059 calving. As indicated previously, the primary risk factors for recumbency are

3060 hypocalcemia, complications associated with calving and injuries. Close observation of

3061 cattle during the transition period (four weeks before and after calving) and particularly

3062 during the periparturient period is essential to correct or treat problems promptly and as

3063 necessary. Transition cow personnel should be well-trained and knowledgeable of

3064 transition cow problems. Early detection and treatment of hypocalcemia (i.e., before the

3065 cow goes down) will reduce the potential for hypocalcemia-related complications.

3066 Cattlemen, dairymen and dairy personnel who manage calving cows need continual

3067 training and updates on proper ways to assist cows with dystocia problems.

132

3068 Finally, since many of the problems are related to injuries from slipping and falling, it is

3069 important that dairy operators be aware of flooring conditions that might predispose to

3070 falls. Some operations keep a log of areas where slips and falls commonly occur. This

3071 information can be used to determine when or if corrective action must be taken, for

3072 example – altering of the flooring surface to increase traction. Owners/managers should

3073 also ensure that personnel move animals with care to avoid needless injury associated

3074 with careless handling and cattle driving procedures. No one should assume that such

3075 information is common knowledge. Good operations continually review their cattle

3076 handling procedures to avoid unnecessary injury to cattle as well as personnel (Stull, et

3077 al. 2007).

3078 Bob Veal

3079 Calves fitting the definition of “bob veal” are those slaughtered within the first few days

3080 of life. Most are male calves from the dairy industry. These are to be distinguished from

3081 “formula-fed (or "milk-fed") veal”, which are older calves raised on a milk formula

3082 supplement.

3083 Veal is one of the most controversial welfare issues in modern agriculture. Those who

3084 oppose the raising of veal generally cite tethering of formula-fed calves in individual

3085 stalls that does not permit the calf freedom to turn around as one of the major breeches of

3086 animal welfare in veal production. However, critical attention was brought to light by a

3087 videotape in 2009 displaying inhumane treatment of calves at a bob veal slaughter plant

3088 in Vermont. Calves appeared to have been skinned alive, kicked, dragged and repeatedly

3089 shocked with electric prods. The crowning blow came when a hidden camera

3090 investigation captured an inspector in the act of coaching a slaughterhouse worker on

133

3091 ways to avoid having the facility shut down. These events resulted in the closing of the

3092 plant.

3093 Neonatal calves require greater effort and care in handling. Since they are removed from

3094 the dam at birth, they tend to imprint on humans. They have little natural fear of humans

3095 and do not exhibit the flight or fight responses normally observed in older calves. Moving

3096 them requires actually picking them up or carefully pointing them in the desired

3097 direction. They are incapable of responding to an electric prod and use of such devices

3098 becomes little more than torture. For busy people unaccustomed to neonatal calf

3099 handling, the process can be painfully slow and cumbersome.

3100 Bob veal calves are typically transported from the dairy to a packing plant or other

3101 gathering location within 24 to 48 hours of birth. Transport to slaughter may require as

3102 much as 12 to 24 hours, animals that have not received an initial feeding of colostrum or

3103 milk arrive at the plant with varying degrees of hypoglycemia and physical exhaustion.

3104 Some of these calves will be non-ambulatory on arrival at the plant, under its current

3105 rules the Food Safety and Inspection Service (FSIS) will permit these animals to be set

3106 apart and held for treatment before being moved to slaughter. The Humane Society of the

3107 United States (HSUS) petitioned FSIS to amend the regulations to require that non-

3108 ambulatory disabled veal calves be condemned and promptly and humanely euthanized.

3109 On April 4, 2011, the AVMA sided with HSUS and recommended that this provision be

3110 repealed to be consistent with its current policy on disabled livestock which states that:

3111 “If an animal is down at a terminal market (e.g., slaughterhouse or packing plant)

3112 Animals that are down should be euthanatized immediately and not taken to slaughter.

3113 However, if swine are down, and are not in extreme distress or do not have an obviously

134

3114 irreversible condition, they may be allowed up to 2 hours to recover. Acceptable

3115 interventions to assist in this recovery include rest, cooling, or other treatments that do

3116 not create drug residue concerns.”

3117 Regardless of the final decision made on the disposition of non-ambulatory calves upon

3118 arrival at packing plants, it is clear that these animals present some of the most

3119 challenging problems for regulators and others concerned for assuring their welfare at

3120 slaughter.

3121 Fetal Effects

3122 A 2002 report suggested that world demand for fetal calf serum was 500,000 liters per

3123 year and growing; a need that would require the harvest of at least 1,000,000 fetuses per

3124 year (Jochems, 2002). To serve this need and safeguard fetal welfare, it is important to

3125 understand what happens to the fetus when its dam is slaughtered.

3126 Behavioral and EEG evidence to date indicates that mammalian fetuses are insentient and

3127 unconscious throughout the first 75 to 80% of gestation (Mellor, 2010). As neuronal

3128 pathways between the cerebral cortex and thalamus become better established, the fetus

3129 develops the capacity for sentience. However, within the protected environment of the

3130 uterus the fetus remains in an unconscious state due to the presence of eight or more

3131 neuro-inhibitors that act on the cerebral cortex to maintain it in a sleep-like state of

3132 unconsciousness. At birth, the combined effects of reduced neuro-inhibition and onset of

3133 neuro-activation contribute to gradual arousal of the mammalian newborn into a state of

3134 consciousness (Mellor, 2010).

3135 These observations indicate that the fetus does not suffer as if drowning in amniotic fluid

3136 when the dam is slaughtered; nor is it likely to experience conscious pain associated with

135

3137 other types of invasive procedures in utero. These studies also support the rationale for

3138 international guidelines on the handling of fetuses suggesting that fetuses should not be

3139 removed from the uterus before the EEG is found to be isoelectric. For example, when

3140 animals are killed by physical methods that include exsanguination, delaying removal of

3141 the fetus from the uterus for a minimum of 5 minutes after hemorrhaging has ceased

3142 generally assures a substantial amount of anoxia-induced damage to the cerebral cortex

3143 that will normally prevent progression toward a return to consciousness (OIE, 2008). If

3144 there is any doubt as to the fetus’s level of consciousness, it should be euthanatized

3145 immediately by captive bolt and adjunctive methods as appropriate.

3146 Additional Considerations: Swine

3147 Non-Ambulatory Swine

3148 Lameness disorders that interfere with locomotion and contribute to non-ambulatory

3149 conditions in pigs include: foot disorders (foot rot, overgrown claws, and torn dewclaws),

3150 leg injuries, leg weakness (epiphysiolyis, apophysiolysis, osteochondritis, arthrosis),

3151 osteomalacia, fractures, arthritis, and various neurological disorders. Although many of

3152 these conditions may not result in non-ambulatory conditions, all are significant causes of

3153 lameness that in their severest form, or when complicated by other conditions, can lead to

3154 non-ambulatory conditions (Straw et al., 1996).

3155 Foot problems are reportedly one of the single most important causes of lameness in sows

3156 (Smith and Robertson, 1971; Dewey, et al. 1993). Slatted concrete floors contribute to

3157 trauma of claws as feet slide outward when the sow attempts to stand. Overgrowth of

3158 claws, particularly on the lateral digits, is a serious problem where sows are kept on non-

3159 abrasive floors such as plastic or steel slats (Straw et al. 1996). Foot rot and claw lesions

136

3160 (erosions, white line disease abscesses and vertical wall cracks) are common disorders as

3161 well with occurrence rates as high as 64% in slaughter weight pigs (Penny et al. 1963).

3162 Results of several studies suggest that osteochondritis (a degenerative disease of the

3163 articular or joint cartilage) is the most common cause of lameness in breeding age

3164 animals. The joints mature by age rather than weight. In rapidly growing animals the

3165 excess load on joints leads to disturbed development of the joint cartilage on both the

3166 physeal and epiphyseal surfaces. This is followed by bony changes that form in response

3167 to damage caused by mechanical stress and load on the joints (Jorgenson and Sorenson,

3168 1998). It is a major cause of leg weakness in growing boars and sows.

3169 Fractures are most often the result of falls on slippery concrete or falls that may occur

3170 during transport. They also result from situations where an animal’s foot or leg becomes

3171 trapped beneath a feeder, in a slat or between pen rails. As the animal struggles to free

3172 itself it fractures the limb. The lameness that results is severe and often manifested by

3173 the carrying of the affected limb. Failure to apply weight to a limb is a good indication of

3174 a fracture. Fortunately, these are not common causes of lameness or non-ambulatory

3175 conditions in pigs (Vaughan, 1969).

3176 In addition to these causes, there are neurological disorders affecting the spinal cord and

3177 brain. An early study by Vaughan suggests that the most common cause of posterior

3178 paralysis in pigs of all ages is compression of the spinal cord secondary to abscessation of

3179 an intervertebral disk, vertebral body or adjacent paravertebral tissues (Vaughan, 1969).

3180 Causes in adult animals are believed to be associated with excess load on vertebral disks

3181 that causes premature disk degeneration or osteochondrosis of the vertebrae. In growing

137

3182 animals spinal abscesses are secondary to tail biting. These cases usually require

3183 euthanasia.

3184 The incidence of transport losses in market weight pigs (dead and non-ambulatory) is

3185 approximately 1% (Ellis et al., 2003; Ellis et al., 2004). In a study to evaluate the effect

3186 of floor space on transport losses, Illinois researchers observed 74 loads of finishing pigs;

3187 one load had 0.39 m2/pig and another 0.48 m2/pig during transport. Investigators

3188 monitored the incidence of non-ambulatory pigs at the farm during loading and at the

3189 plant after unloading. Of 12,511 pigs transported, 32 (0.26%) were identified as non-

3190 ambulatory on the truck at the farm, 29 (0.23%) were dead on arrival at the plant and 106

3191 (0.85%) were non-ambulatory at the plant. For 65 of 74 loads, pigs that were non-

3192 ambulatory at the plant were divided into two groups: non-ambulatory injured and non-

3193 ambulatory non-injured. The ratio of non-injured (0.55%) to injured pigs (0.24%) was

3194 2:1. Overall, the total number of pigs lost in 74 loads was 135 (1.08%), which is

3195 comparable to previous studies. Increasing floor space did not affect the incidence of

3196 non-ambulatory injured pigs at the plant, but it did reduce the percentage of non-

3197 ambulatory non-injured pigs and thus total losses at the plant (Ritter et al., 2006).

3198 The Prevention of Non-Ambulatory Swine

3199 Lameness disorders involving the foot and leg are complicated. There is no “one

3200 solution” to correcting or preventing these conditions. But, floors are a major

3201 consideration in the prevention of foot and leg problems. Pigs housed on slatted floors

3202 had an injury rate of 44% compared with 28% of pigs housed on solid floors (MAFF,

3203 1981). Concrete floors caused more foot and leg problems than did softer earthen floors

3204 or deep straw bedded surfaces and perforated floors contributed to an increase in injuries

138

3205 (Nakano et al., 1981). In farrowing crates plastic and steel slats caused more lameness

3206 than did solid floors (Nakano et al., 1981). One could conclude from these observations

3207 that the best type of floor is a solid floor with soft bedding.

3208 Flooring surfaces should provide good footing to prevent slips and falls, however

3209 achieving the ideal balance between adequate traction and a slippery surface is difficult.

3210 When surfaces are too soft or non-abrasive claw horn wear is reduced then claws

3211 overgrow rapidly. Foot trimming is required in these conditions or the overgrowth will

3212 lead to claw deformities that also create strain on tendons of the lower leg. On the other

3213 hand, excessively abrasive flooring surfaces accelerate wear and may contribute to foot

3214 problems from excessive wear of the sole.

3215 Softer flooring conditions are also believed to be beneficial for decreasing the incidence

3216 of osteochondritis. Even more important to the prevention of leg weakness caused by

3217 osteochondritis is to avoid overfeeding of gilts during the growing period. Gilts fed ad-

3218 libitum were culled earlier and at a higher rate than pigs as a consequence of leg

3219 weakness as compared with gilts fed on a controlled feeding schedule (Jorgensen and

3220 Sorensen, 1998). Research also demonstrates that pigs need exercise to increase

3221 muscular strength and to develop proper agility on differing flooring systems (Fredeen

3222 and Sather, 1978).

3223 Other factors that can contribute to causing downer pigs is the Halothane gene. Market

3224 pigs that were carriers (heterozygotes) had 0.27% death losses and if they were

3225 homozygous negative 0.05% (Murray and Johnson, 1998). Fortunately, the Halothane

3226 gene has been bred out of many swine herds. It is not now a major cause of losses in the

3227 U.S. (Ritter, 2009). High doses of the beta-agonist ractopamine may contribute to

139

3228 downers and make pigs more difficult to handle (Marchant-Forde et al., 2003). It may

3229 also cause hoof cracking (Poletto et al., 2009). Pigs that have received little or no contact

3230 with people in their pens on the farm prior to loading may be more likely to pile up and

3231 be difficult to move. Swine that have had previous experiences with handling will be

3232 easier to move (Geverink et al., 1998; Abbott et al., 1997; Lewis et al., 2008). Producers

3233 should walk their pens during finishing to get pigs acclimated to people walking through

3234 them. This will make handling and loading easier (Grandin, 2010). Fatigued non-

3235 ambulatory pigs may be reduced because the pigs will be less likely to become agitated

3236 during truck loading or during handling at the plant.

3237

3238 Rabbits

3239 Handling Procedures for Rabbits

3240 In the United States, rabbits are not covered by the HMSA and federal inspection of

3241 rabbit meat is voluntary, although individual states may have rabbit-specific inspection

3242 requirements. (Fanatico, 2005) There are few USDA inspected plants in the U.S that

3243 process rabbits, and most of the available information on rabbit processing comes from

3244 Europe, where commercial rabbit processing is more common. For interstate commerce,

3245 rabbits not voluntarily inspected at slaughter by USDA are under the regulatory oversight

3246 of the Food and Drug Administration (FDA).

3247 Rabbits are prey animals that retain behavioral patterns similar to their wild counterparts

3248 (Gunn and Morton, 1995), and the harvesting, transport and handling of rabbits prior to

3249 slaughter is stressful (Cavani and Petracci, 2004). A twofold increase in serum cortisol

3250 was seen in rabbits after transport regardless of whether they endured rough or careful

140

3251 handling during loading, indicating that the entire process was stressful (Mazzone et al.,

3252 2010). Other biomarkers of stress in rabbits include elevations in serum glucose, serum

3253 triglycerides, serum aspartate aminotransferase (AST), alanine aminotransferase (ALT),

3254 glutamyltransferase (GGT), lactate dehydrogenase (LDH), creatinine kinase (CK), and

3255 myocardial creatinine kinase (CK-MB), as well as decreases in serum tetraiodothyronine

3256 (T4) (Subuncuoglu et al., 2011). Elevations of these values have been reported in rabbits

3257 during transport and lairage (Vignola et al., 2008).

3258 The pre-slaughter environment presents the combined effects of many emotional and

3259 physical factors. Multifactor (social and non-social) stressors involved in the pre-

3260 slaughter process can affect rabbit welfare as well as meat quality (Subuncuoglu et al.,

3261 2011). Social and non-social stress may occur due to changes of environment: i.e.,

3262 new/unfamiliar habitat, separation of familiar companions, presence of strangers or

3263 exposure to a strange group, destabilization of an established hierarchy, aggressive

3264 encounters, alarm vocalizations, social disturbances and handling, disruption of the social

3265 group, changes in social structure; separation and/or mixing with unfamiliar animals,

3266 food deprivation, and climatic conditions. High stocking densities in crates should be

3267 avoided to minimize distress and trauma due to intraspecies aggression; the

3268 recommended minimum floor space for 12 week old rabbits is 1800 cm2 (Buil et al.,

3269 2004).

3270 Critical points during transport are waiting time at the farm before loading, loading,

3271 ventilation and temperature during transport, loading stops, unloading, duration of

3272 lairage, and environmental conditions during lairage (Buil et al., 2004). Although some

3273 research has suggested that transport conditions are more important than the time of the

141

3274 journey (Maria et al., 2006), other studies have shown decreased welfare and carcass

3275 quality in rabbits experiencing prolonged transport to slaughter (Lambertini et al., 2006).

3276 Ideal temperatures for rabbit transport are between 50° and 68° F, and temperatures

3277 above 95° F or humidity below 55% are detrimental to rabbit welfare (Vignola et al.,

3278 2008. It is important to remember that when transport crates are stacked, rabbits located

3279 centrally in the stack may be prone to hyperthermia and poor ventilation, while rabbits in

3280 crates on the periphery may be subject to hypothermia (Cavani and Petracci, 2004).

3281 Crates for transport and lairage should have solid floors to prevent urine and feces

3282 transfer from higher crates (Cavani and Petracci, 2004). Multi-floor cage stands can

3283 adversely affect welfare if rabbits are left in them for long periods of time (Buil et al.,

3284 2004).

3285 Providing adequate ventilation, preventing exposure to extreme temperatures, providing

3286 food and water for prolonged lairage, and avoiding long delays between loading and

3287 transport or arrival and stunning are important factors in maintaining rabbit welfare in the

3288 pre-slaughter period (Buil et al., 2004). Extended lairage times should be avoided and

3289 water should be provided when delays between arrival and slaughter are expected; this is

3290 not only good for animal welfare but reduces live weight and carcass losses (Buil et al.,

3291 2004). Lairage areas should be protected from the elements to minimize exposure to

3292 temperature extremes.

3293 Commercial processing of rabbits in the U.S. is generally performed in plants designed to

3294 process poultry. (ISAMPA, 2008) Rabbits should be stunned prior to shackling;

3295 shackling and hanging of conscious rabbits should be avoided. Shackling has been

3296 shown to be painful and distressful to poultry (Bednanova et al., 2007; Kannen et al.,

142

3297 1997), and without research to show differently, it must be assumed that it is also painful

3298 and distressing to conscious rabbits. Although one paper on halal slaughter of rabbits

3299 suggested that shackling of rabbits by one leg and simultaneously performing deep throat

3300 cuts did not result in signs of rabbit distress (Lopez et al., 2008), there are questions about

3301 their methodology. The primary parameter that was used to determine distress was the

3302 presence of vocalization in the rabbits; however, the throat cuts severed the tracheas of

3303 these rabbits, thereby making vocalization impossible. The authors indicate that other

3304 potential signs of distress/sensibility, such as movement of mouth or eye reflexes, were

3305 not recorded.

3306 Successful stunning is characterized by cessation of respiration, excessive salivation and

3307 increased motor activity consisting in the immediate onset of tonic spasm followed by

3308 weak to heavy clonic spasms, hypersalivation (Anil et al., 2000; Schutt-Abraham et al.,

3309 1992). Not all animals develop convulsive muscle activity, and cessation of rhythmic

3310 breathing is considered a more reliable indicator of a successful stun (Anil et al., 2000),

3311 although some consider lack of corneal reflex as the best measure of insensibility in

3312 rabbits (Rota Nodari et al., 2008).

3313 Maria (2001) studied five methods of electro-stunning for commercial rabbits (n>50)

3314 using variable voltages and frequencies. Voltages less than 19 V were not recommended.

3315 The most common parameters used in commercial facilities were 49 V, 5.6 ms, 189 Hz

3316 for three seconds. These parameters did not produce changes in muscle pH. (Anil et al.,

3317 1998) recommends a minimum current of 140 mA by application of 100 V to obtain

3318 adequate stunning (Anil et al., 2000). The European Food Safety Authority (EFSA)

3319 recommends that 400 mA be used in head-only stunning devices (EFSA, 2009).

143

3320 Impedance from rabbit fur can result in a wide range of achieved currents, resulting in

3321 variation in the effectiveness of the stun. Stunning devices should employ an

3322 impedance/resistance sensing device that will prevent discharge in the event of

3323 insufficient stunning current; this will minimize the risk of inadequate and painful mis-

3324 stunning. The stunned state lasts for at least 22 seconds, although in adequately stunned

3325 rabbits insensibility lasts for at least 71 seconds (Anil et al., 2000).

3326 Captive bolt apparatus designed for water fowl can be used on rabbits (Schutt-Abraham

3327 et al., 1992). With penetrating captive bolts, the best stunning results are obtained with a

3328 shot to the parietal bone near the sagittal line but without hitting bone sutures (Schutt-

3329 Abraham et al., 1992). This is achieved by placing the captive bolt slightly paramedian

3330 on the front as close to the ears as possible (see figure). It is essential to stabilize the

3331 head to prevent misses.

3332

3333 Recommended placement for captive bolt slaughter of rabbits

3334 Following electrical or captive bolt stunning, rabbits are immediately shackled and

3335 exsanguinated. Rabbits must be killed within 35 seconds of electrical stunning or they

3336 may recover consciousness (Buil et al., 2004). In commercial rabbit plants in Europe,

144

3337 exsanguination commences within 5 to 8 seconds following stunning, with many

3338 managers allowing no more than an average of 15 seconds (Rota Nodari et al., 2008; Buil

3339 et al., 2004). Bleeding time is reported to be 10 to 12 seconds (EFSA, 2006) to 2 to 3

3340 minutes (Cavani and Petracci, 2004).

3341 Decapitation is not commonly employed in the commercial slaughter of rabbits, but is

3342 sometimes used for on-the-farm slaughter (Mason, 2009). Operator competence is

3343 required to perform decapitation in a humane fashion. The operator must be familiar

3344 with the technique and able to accurately place the blade high on the neck, ideally at the

3345 level of the first vertebra. Blades used for decapitation must be maintained properly;

3346 sharp enough to sever the entire head without need for more than one blow. Rabbits must

3347 be restrained to prevent them from moving away from the blade.

3348 Cervical dislocation is also used for on-the-farm slaughter of rabbits (Mota-Rojas et al.,

3349 2008). When properly employed, this technique can be a quick and humane method of

3350 slaughter, but if done incorrectly it has the potential to induce pain and distress in the

3351 animals. This method may be found to be aesthetically displeasing to those performing

3352 or observing the technique.

3353 Those performing cervical dislocation should be familiar with the technique through

3354 practice on dead animals before attempting cervical dislocation on live animals. For

3355 immature rabbits, the head is held in one hand and the hind limbs in the other. The animal

3356 is stretched and the neck is hyperextended and dorsally twisted to separate the first

3357 cervical vertebra from the skull (Clifford, 1984; Hughes, 1976). For larger rabbits,

3358 mechanical cervical dislocation using a stainless steel tool (Commercial Cervical

3359 DislocatorTM) has been developed that allows for rapid and efficient cervical dislocation

145

3360 (Commercial Cervical Dislocator). The stainless steel tool is affixed to a wall or post and

3361 the animal’s head is slid down into a notch. The operator then uses both hands to pull up

3362 and out, resulting in rapid cervical dislocation.

3363

3364 Slaughter of Food Fish Intended for Human Consumption 3365 3366 General Considerations

3367 In the United States, fish are not covered by the HMSA. In addition, these Guidelines do

3368 not address fishing or wild caught aquatic animals for commercial or recreational

3369 purposes. Euthanasia, depopulation and the transport of fish can be found in separate

3370 AVMA documents devoted to those topics. According to the AVMA Guidelines on

3371 Euthanasia, the term “slaughter” is used primarily to describe the humane killing of

3372 animals intended for human consumption for food or other uses (e.g., commercial

3373 fisheries for fish meal and oil production). While there is an ongoing debate about the

3374 ability of fishes to feel pain or otherwise experience compromised welfare, they do

3375 respond to noxious stimuli and there is evidence that fish can be fear conditioned (Dunlop

3376 et al., 2005). According to the assessment by Dr. James D. Rose:

3377 “Behavioral responses to noxious stimuli are separate from the psychological

3378 experience of pain, such that behavioral responses to these stimuli can occur in the

3379 absence of pain experience. Awareness of pain in humans depends on specific regions of

3380 the cerebral cortex. Fishes lack these brain regions and thus lack the neural

3381 requirements necessary for pain experience…Potentially injurious stress responses, as

3382 opposed to pain or emotional distress, are the proper matter of concern in considerations

3383 about the welfare of fishes”(Rose 2002).

146

3384 These ideas are supported by Rose 2007; Wynne 2010; and Browman 2011 but debated

3385 by others such as Braithwaite 2010, Sneddon 2009, and Huntingford 2006. According to

3386 Victoria Braithwaite,

3387 “research demonstrating the ability for nociception in teleosts is compelling”

3388 (Braithwaite 2007).

3389 In addition, consideration should also be given to the fact that rapid dispatch or killing of

3390 fish results in improvement in flesh quality (Robb, 2002). Consequently, slaughter

3391 methods should be employed that minimize the potential for physiological stress in food

3392 fish and that ensure conditions appropriate for the highest meat quality possible. These

3393 methods should be continually modified with new technology and as new knowledge

3394 about the physiology and anatomy of each species is acquired.

3395 Preparation and Environment for Food Fish Slaughter:

3396 The harvesting of fish occurs in broad terms in two very different environments. Fish

3397 remain the last major food harvested in the wild. Wild catch fish are caught in many

3398 different ways and harvested such that the number of fish varies greatly. On the other

3399 hand, the increase in the intentional rearing of fish, i.e., aquaculture, provides an

3400 opportunity to control the harvesting and slaughter of fish in ways that are not possible in

3401 the wild.

3402 This section will consider aquaculture situations where fish are removed from their

3403 “growth” habitat and are being moved to slaughter. The preparation and environment

3404 used for fish being held for slaughter is an important consideration in the slaughter

3405 process and should avoid stress to the fish as much as possible. First of all, water quality

3406 should be similar to the environment from which the fish originated, or should be

147

3407 optimized for that species and situation, i.e., the change should not be too drastic from

3408 normal conditions to lead to stress, for the duration of holding before slaughter. Water

3409 quality should be monitored including parameters such as oxygen, pH, CO2, salinity,

3410 ammonia, and temperature and optimized for the species of fish in question. Any need

3411 for changes should be done gradually to allow the fish to adjust. Supplemental aeration

3412 and temperature control may be used when necessary. The addition of salt (2 to 8 g/L) to

3413 the water can also decrease stress to freshwater fish during holding periods (Wurts,

3414 1995). Handling and crowding, as well as time out of water, should be minimized as

3415 much as possible to control and minimize physiological stress to fishes. In addition, nets

3416 and tanks should be designed to minimize physical injuries by using smooth materials

3417 and surfaces appropriately designed for use with fish, and by checking on a regular basis

3418 for holes, tears, or other changes that would compromise the integrity of the materials

3419 used.

3420 Methods of Slaughter for Food Fish

3421 The following methods, or a combination of the following methods, can be applied for

3422 slaughter of food fish, providing they are performed using proper equipment, properly

3423 maintained, by trained personnel who are regularly monitored for proficiency.

3424 Preferred Methods

3425 Percussive Stunning

3426 Percussive stunning is conducted by a blow to the head, often applied manually with

3427 blunt force trauma using a hand-held club called a priest or by automated percussive

3428 stunning. The manual method should be a rapid, accurately-placed blow of sufficient

3429 energy to the cranium with an appropriate sized club to cause immediate unconsciousness

148

3430 and potentially death. The location of the blow should be targeted at the area where the

3431 brain is closest to the surface of the head and where the skull is at its thinnest (HSA

3432 Guidelines). It can be a stun and kill method or may be followed a secondary kill step

3433 such as exsanguination (the cutting of the gill arches to bleed the fish) or pithing

3434 (destruction of brain tissue). Operators of the manual percussive stunning method should

3435 be trained in the proper location of the blow to the head and should be given frequent

3436 breaks and refreshed often to avoid operator fatigue. Automated systems require training

3437 for operators on a regular basis and a preventative maintenance program to ensure the

3438 proper functioning of the equipment.

3439

3440 Percussive stunning of halibut (Humane Harvesting of Halibut, HSA: Humane Slaughter Association)

3441 Pithing

3442 This method is similar to spiking, coring, or “ike jime”. A spike is quickly inserted into

3443 the brain of the fish to cause immediate brain death, resulting in it being both a stun and

3444 kill method. As mentioned above, pithing can be used either as a one-step stun and kill

3445 method or as a secondary kill method. The technique of ike jime originated in Japan with

149

3446 the insertion of the spike directly into the hind portion of the brain of the fish. In iki jime

3447 (pronounced “ick-ee jee-mee”) a spike or awl is inserted directly into the brain causing

3448 immediate brain death and the cessation of all motion. Spiking, or iki-jime, will kill the

3449 fish instantly and prevent stress to the fish. There are two main iki-jime methods: from

3450 the top of the head or through the gill cover. The first method is used for most medium-

3451 sized fish where a sharp spike is driven into the brain from the right side of the head. The

3452 position of spiking is diagonal and about 2 cm behind the eye. Smaller fish can be spiked

3453 through the gill opening with a sharp knife. This will both spike and bleed the fish. The

3454 aim of both methods is to destroy the hind brain of the fish, which is the part of the brain

3455 controlling movement (FAO Corporate Document Repository). Operators using this

3456 method should be trained in the proper location and timing of the pithing process to

3457 ensure minimal stress and rapid brain death for the fish.

150

3458 Spiking or iki-jime methods killing the fish instantly (FAO Corporate Document Repository)

3459

3460 Gunshot

3461 This technique is primarily used with large fish such as tuna. When aimed correctly, the

3462 bullet enters the brain to cause immediate damage and brain death, resulting in it being

3463 both a stun and kill method. Operators using this method should be trained in the proper

3464 aim required to ensure the correct location of the bullet to the brain of the fish and to

3465 insure human safety (see Techniques: Gunshot for further safety information).

3466 Electrocution

3467 An electric current is passed through the water containing the fish for slaughter. The

3468 voltage/amperage conditions of the electric current should be sufficient to not only stun

151

3469 the fish creating immediate unconsciousness (electronarcosis) but also to kill the fish

3470 (electrocution). However, the level of current should not be so strong as to cause damage

3471 to the carcass. Operators using this method should be sufficiently trained in the level of

3472 electrical current appropriate to be used for the species of fish in question as well as in

3473 safety measures for themselves.

Table 3. The proportion of Atlantic salmon stunned when exposed to various electrical field strengths (E = Vrms/m) and current durations (1–6 s) of, one-phase sinusoidal, 50-Hz AC. Also provided are mean durations of surgical anesthesia (stage 4) and deep narcosis (stage 3), as described in Table 1. The duration of unconsciousness is measured in seconds from the moment ofelectric exposure (Roth 2003).

3474

3475 The following methods have animal welfare concerns of differing degrees due to the

3476 potential for physiological stress to the fish. Although these methods are not seen as

3477 optimal in regards to animal welfare, they may still be preferable to other techniques such

3478 as anoxia through dewatering.

3479 Other Methods

3480 Carbon Dioxide

3481 Fish are immersed in CO2 saturated water until loss of consciousness. Concentrations of

3482 CO2 must be maintained at the appropriate levels and monitored by measuring the pH of

3483 the holding water (pH level 4.5). This method is most often used as the first step of a two

152

3484 step process with another method such as exsanguination. On initial exposure to CO2 in

3485 several species, a quick and violent reaction has been reported such as repeated

3486 swimming around, attempts to escape from the tub, and abnormal activity (Poli, 2005).

3487 Chilling on Ice

3488 Fish are chilled down to 1°C to quickly lower the core body temperature of the fish. This

3489 method is used as either a one step process or as a first step followed by a secondary kill

3490 step such as exsanguination. Although fish display vigorous movement upon chilling,

3491 live-chilling decreases stress as measured by plasma glucose when compared to no

3492 chilling before slaughter (Skjervold, 2001).

3493 Exsanguination Without Prior Stunning

3494 Gill arches are cut to cause bleeding of the fish and ultimately death as a one step process

3495 without a prior stunning method as a first step. This method first involves removal of the

3496 fish from water which causes vigorous movement of the fish. Once the cut into the gills

3497 is made these reactions are dramatically increased and vigorous head shakes and tail flaps

3498 are seen (Benson 2004).

3499 Conclusions

3500 Aquaculture slaughter techniques are very diverse and fish species vary in their response

3501 to different methods (Ashley, 2006) such as sensitivity to oxygen deprivation (Morzel et

3502 al, 2003). For example, sea bass killed by chilling in ice water had lower plasma glucose

3503 and lactate levels and showed less marked behavioral responses than those killed by other

3504 methods, in particular by asphyxia in air and electro-stunning (Huntingford et al, 2006).

3505 Therefore, slaughter techniques should be continually researched and determined

3506 specifically for the food fish species in question.

153

3507 Handling and Slaughter of Ratites

3508 Ratites are flightless birds that include the ostrich, emu, and rhea. Currently, ostrich and

3509 emu are raised in several countries for slaughter purposes. Slaughter facilities for ratites

3510 include: commercial plants specifically designed for these birds, custom slaughter plants

3511 that process a broad range of species, and plants previously utilized for a different species

3512 that have been adapted for ratites (e.g., a beef slaughter plant adapted for ostrich).

3513 Regardless of the slaughter facility used, care should be taken to avoid standing in front

3514 ratites during handling or catching. They can kick forward and a kick from a slaughter

3515 weight bird can cause severe injury from the last phalanx of the third toe which is pointed

3516 and carries a claw. It is advised to stay at the side or toward the rear of the bird for

3517 handling purposes. Toe-trimming of the birds is a husbandry option but the third toe

3518 plays a primary role as a lever for balance, exertion of traction forces and directional

3519 impetus during locomotion (Schaller et al., 2005) and trimming can negatively affect

3520 their balance making the birds prone to slipping in wet conditions (Glatz, 2010).

3521 When working with slaughter stage ratites, highly stressed and aggressive birds should be

3522 caught first to prevent agitation within the rest of the group. Individual ostriches can be

3523 captured by using a shepherd’s crook or by catching the beak in one hand and pulling the

3524 bird’s head down and in the direction you wish the bird to move. Another option for

3525 moving an individual bird is described in the Ostrich Business Chamber’s (OBC) Code of

3526 Conduct:

3527 “A minimum of three handlers is needed to restrain an adult bird to avoid injuries to both

3528 the ostrich and handlers. A handler must be positioned at each side of the ostrich holding

3529 the wings. One of these handlers must be positioned between the wing and tail, taking

154

3530 hold firmly of both the wing and the tail. One handler should be employed at the head

3531 where he holds the neck-head junction while immediately putting a blindfold or hood

3532 over the head of the ostrich. The handler at the head must prevent injury to the soft beak

3533 as well as interference with respiration. After hooding, ostriches will be calm and the

3534 handler can move to the wing, while the handler at the wing moves backwards to the tail

3535 from where the ostrich can be steered.”

3536 A shepherd’s crook is typically not required for emu and they do not respond well to

3537 hooding unless they have been restrained prior to placement of the hood (Glatz, 2000).

3538 Lifting the tail up and holding the head down make it more difficult for ratites to forward

3539 kick and injure personnel.

3540 For lairage, it is important that all pens be round, hexagonal, or octagonal in shape. This

3541 prevents the birds from crowding into the corners of the pens and injuring one another.

3542 Additionally, side walls should be 1.7-2.0 m high to prevent birds from seeing

3543 distractions outside of the pen (Hoffman and Lambrechts, 2011). Walls should also be

3544 constructed to handle the force of birds running or pushing against them (Hoffman and

3545 Lambrechts, 2011). It should also be noted that while ratites are flightless birds they can

3546 jump over low fences (Hoffman and Lambrechts, 2011). It is important to avoid startling

3547 the birds as they will attempt to flee and will injure themselves and each other (Hoffman

3548 and Lambrechts, 2011). Any unexpected behavior by personnel may startle the birds and

3549 result in rapid evasive behavior. Low light levels and minimal noise in lairage may help

3550 birds remain quiet and calm (Hoffman and Lambrechts, 2011). It is best to avoid mixing

3551 birds from different farms as they can be become aggressive towards one another. Water

3552 should always be freely available to the birds during lairage. Grooved cement floors can

155

3553 cause birds to slip and metal grids placed on top of cement can dissuade birds from

3554 settling and lying down. A floor system that is suitable for ratites is metal mesh (1 to 1.5

3555 centimeter sided square holes) raised above a concrete floor (Hoffman and Lambrechts,

3556 2011).

3557 There are no universally agreed upon stunning methods for ratites. A large number of

3558 ostrich are slaughtered annually in South Africa and electrical head-only stunning

3559 performed with hand-held tongs is the most commonly used method. The recommended

3560 electrical stunning parameters for ostrich in South Africa are a current of 0.4 to 0.6 Amps

3561 at 90 tp 110 Volts for a duration of 4 to 6 seconds (OBC, 2011). Glatz recommends

3562 stunning emus using 120 Volts at 1.2 Amps for 10 seconds and ostrich using 120 Volts at

3563 1.2 Amps for 15 seconds (Glatz, 2000). An electrical stunning current greater than 0.4

3564 Amps at 50 Hz alternating current used in head only application prevented recovery in

3565 90% of ostrich when they were bled within 60 seconds (Hoffman, 2005). The return of

3566 rhythmic breathing movements indicates the first stages of recovery in birds following an

3567 electrical stun. (Wotton and Sparrey, 2002) Effective stunning can be presumed when

3568 epileptiform activity is seen (i.e. rigidity with flexed legs [tonic phase] followed by

3569 kicking of varied intensity [clonic phase]) (OBC, 2011). The Canadian Food Inspection

3570 Agency (CFIA) Manual of Procedures pertaining to ratites recommends the following for

3571 electrical stunning:

Birds Amperage Volts Frequency Time (sec)

Ostriches, Rhea, Emus Not hooded 0.12- 230-300 50-60 4-6

0.4

Ostriches, Rhea, Emus Hooded 0.4 230-300 50-60 4-6

156

3572 *adapted from CFIA Annex A Species Specific Stunning Guidelines Red Meat Species

3573 The tongs should be placed on both sides of the head behind the eyes and just over the

3574 outer ear openings. (CFIA, 2012)

3575 3576 Arrows indicate where the electrodes should be applied to each side of the animal's head. 3577 3578 Chapter 7 of the FAO Guidelines for Humane Handling, Transport and Slaughter of

3579 Livestock recommends 1.5 to 2 Amps, 90 Volts for 10 to 15 seconds for electrical

3580 stunning of ostriches (FAO, 2012).

3581 During traditional stunning with hand-held tongs birds are held in a restraining area by

3582 gentle pressure applied from behind on the tail feathers. The restraining area is often a

3583 V-shaped structure high enough that the stunning operator is not kicked. After (or

3584 during) stunning the bird is rocked backwards and a leg clamp is placed over the legs

3585 immobilizing the birds and allowing them to be shackled. The birds are then hoisted onto

3586 a 3.4 meter rail and conveyed to an exsanguination area. Some commercial ratite

3587 slaughter plants now use a new restraining and stunning mechanism that completely

3588 encompasses the bird in a padded clamp holder that restrains the legs and body at

3589 strategic points. The head of the bird is placed into a box where the electrical current is

157

3590 applied. While the bird is being electrically stunned the box rotates 180 degrees so that

3591 toe clamps can be applied without any danger to the stunning operators. The box is then

3592 opened and the bird is hoisted and conveyed for exsanguination (Hoffman, 2005).

3593 An air powered captive needle pistol can also produce an effective stun in birds (Labooij

3594 et al., 1999a,b). When using a captive needle pistol the needles should be applied at the

3595 intersection of two imaginary lines drawn from the ear on one side of the head to the

3596 inner corner of the eye on the other side (Labooij et al., 1999a,b). In a report to the

3597 American Ostrich Association, the Texas Agricultural Extension Service noted the use of

3598 a Schermer captive bolt stunner for the birds (Harris et al., 1994). The CFIA Manual of

3599 Procedures pertaining to ratites recommends a captive bolt device with a short bolt and

3600 the smallest charge appropriate for poultry or rabbits applied to the top of the head at the

3601 midpoint of an imaginary line between the out ear openings (CFIA, 2012).

3602 3603 Arrow indicates the direction that the stunning device should be pointed and the entry point at the top of the 3604 animal's head. 3605 3606 The OBC also finds captive bolt stunning to be acceptable (OBC, 2011). However,

3607 Chapter 7 of the FAO Guidelines for Humane Handling, Transport and Slaughter of

158

3608 Livestock states that a captive bolt gun is not suitable for stunning ostriches as “their

3609 brain is small and lobulated, and the bolt does not produce proper concussion” (FAO,

3610 2012).

3611 Birds should be bled immediately after stunning (within 60 seconds; OBC 2011) with a

3612 complete ventral neck cut that severs both carotid arteries and both jugular veins and/or

3613 thoracic sticking. CFIA recommends that the birds are bled out via a complete ventral

3614 cut of the neck (both carotid arteries) or a thoracic stick within 15 seconds of stunning so

3615 that consciousness is not regained. Anecdotally there is better and faster bleed out when

3616 both the neck cut and thoracic stick are performed.

159

3617 References

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3846 Design of Facilities and Slaughter Process for Religious Slaughter 3847 3848 Handling Procedures at Slaughter Plants for Hoofstock

3849 Steps 1-5

3850 Arrival at the Plant, Unloading, Receiving, Lairage and Handling procedures are

3851 covered in the Design of Facilities and Slaughter Process chapter of these Guidelines.

3852 The procedures for these steps are the same regardless of whether the animals will be

3853 slaughtered via conventional or religious methods.

3854

3855 Step 6—Restraint

3856 There are various methods used to restrain and position the animal for religious

3857 slaughter. In the U.S., there is an exemption from the Humane Methods of Livestock

3858 Slaughter Act (HMSA) for religious slaughter and methods for restraining the animal for

3859 religious slaughter are outside the jurisdiction of the U.S. Department of Agriculture’s

3860 Food Safety and Inspection Service (USDA FSIS) regulations although Congress has also

3861 declared religious slaughter to be humane. The area covered by the handling exemption

3862 has been called the area of “intimate” restraint by FSIS. The HMSA specifically declares

3863 humane (b) by slaughtering in accordance with the ritual requirements of the Jewish faith

3864 or any other religious faith that prescribes a method of slaughter whereby the animal

3865 suffers loss of consciousness by anemia of the brain caused by the simultaneous and

3866 instantaneous severance of the carotid arteries with a sharp instrument and handling in

3867 connection with such slaughtering. However, all procedures outside this area, which

3868 many meat inspectors call the “bubble” but are beyond the area of intimate restraint are

3869 subject to FSIS oversight the same as conventional slaughter. Unloading animals from

167

3870 transport vehicles, lairage, driving the animals to the restraint point and insuring that after

3871 slaughter that the animal is unconscious with no corneal reflex before invasive dressing

3872 procedures begin are under FSIS jurisdiction, the same as conventional slaughter.

3873 Detection of Problems

3874 There are two issues from an animal welfare standpoint which occur during

3875 religious slaughter which uses a neck cut to create unconsciousness. They are stress, pain

3876 or discomfort caused by how the animal is held and positioned for religious slaughter and

3877 the throat cut itself. Because the HMSA regulations exempt restraint of animals for

3878 religious slaughter from the regulations that apply to restraint for conventional slaughter,

3879 some small religious slaughter plants use stressful methods of restraint such as shackling

3880 and hoisting of live animals even though more welfare friendly restraint equipment is

3881 available. Research has clearly shown that upright restraint is less stressful than

3882 shackling and hoisting for sheep and calves (Westervelt et al., 1978). Restraining cattle

3883 on their backs for over a minute caused more vocalization and a greater increase in

3884 cortisol than upright restrainer in a standing position for a shorter period of time (Dunn,

3885 1990). The OIE also recommends that stressful methods of restraint, such as shackling

3886 and hoisting, shackling and dragging, and leg clamping boxes should not be used and

3887 suspension of live cattle, sheep or goats or other mammals by their legs, is not permitted

3888 in the United Kingdom, Canada, Western Europe, and many other countries. Fortunately

3889 most mid-large religious slaughter plants in the U.S. have stopped this practice due to

3890 concerns for both animal welfare and worker safety. Conversion of a system that used

3891 shackling and hoisting to a conveyor restrainer reduced worker injuries (Grandin, 1988).

168

3892 Upright restraint is less stressful for both mammals and poultry compared to being

3893 suspended upside down (Westervelt et al., 1976; Bedanova et al., 2007; Kannen et al.,

3894 1997). Sheep were less willing to move through a single file chute after having been

3895 subjected to inverted restraint compared to being put into a restraint device in an upright

3896 position (Hutson, 1985). In two different plants where cattle were suspended by one back

3897 leg, the percentage of cattle that vocalized varied form 30 to 100% (Grandin, T. personal

3898 communication, 2012). Increased percentages of cattle that vocalize (mooing or

3899 bellowing) during restraint is associated with increased cortisol levels (Dunn, 1990). In a

3900 study at 10 plants, 99% of the cattle vocalizations during handling and restraint were

3901 associated with an obvious aversive event such as the use of electric prods or excessive

3902 pressure from a restraint device (Grandin, 1998). In cattle, vocalization scoring is

3903 routinely used to monitor handling and restraint stress (Grandin, 2012a; 2010) and no

3904 more than 5% vocalization (3% for non-religious animal slaughter) is acceptable

3905 according to the American Meat Institute standards (Grandin, 2012a). The difference in

3906 the percentages for acceptable relates to the differences in handling between the two

3907 procedures. Vocalization scoring does not work for evaluating the handling and restraint

3908 stress in sheep because they usually do not vocalize in response to pain or stress. This

3909 may be due to an instinctual inhibition of vocalization in response to the presence of

3910 predators (Dwyer, 2004). Research is needed to evaluate vocalization as a method to

3911 evaluate stress in goats. For mammals, the following methods of restraint are highly

3912 stressful for conscious mammals and should not be used: hoisting and suspension by one

3913 or more limbs, shackling by one or more limbs and dragging, trip floor boxes that are

3914 designed to make animals fall and leg clamping boxes. Even though suspension is

169

3915 stressful for conscious poultry, such as chickens and turkeys, it is used in a vast majority

3916 of all U.S. poultry plants for both conventional and religious slaughter and with attention

3917 to handling details and proper equipment the stress can at least be minimized.

3918 Corrective Action for Problems with Restraint

3919 For the religious slaughter of cattle, restraint devices are available that hold the

3920 animal in either in an upright position or inverted onto their backs. Smaller ruminants,

3921 such as sheep or goats, can be held in an upright position by people or placed in a simple

3922 restraint device (Westervelt et al., 1976). Large heavy animals, such as cattle or bison,

3923 must be held in a mechanical device that holds them in either an upright position,

3924 sideways position or which inverts them onto their backs. Vocalization scoring of cattle

3925 can be used to both detect serious welfare problems during restraint of cattle and to

3926 document improvements in either design or operation of restraint devices. In cattle, when

3927 restraint devices for religious slaughter are operated poorly or have design problems,

3928 such as excessive pressure applied to the animal, 25 to 32% of the cattle vocalized

3929 (Bourquet et al., 2011; Grandin, 1998). Reducing pressure applied by a head holding

3930 device reduced cattle vocalizations from 23% of the cattle to 0% (Grandin, 2001). These

3931 problems can occur in both upright and rotating boxes. When the equipment is operated

3932 correctly, the percentage of cattle that vocalize will be under 5% (Grandin, 2005, 2012b,

3933 2010). Inversion for over 90 seconds in a poorly designed rotating box had a higher

3934 percentage of cattle vocalizing and higher cortisol levels compared to holding in an

3935 upright restraint box (Dunn, 1990).

3936 Information on the correct operation and design of upright restraint devices for

3937 religious slaughter can be found in Grandin (1992, 1994), Grandin and Regenstein

170

3938 (1994), and Giger et al., 1977). Upright restraint in a comfortable upright position is

3939 preferable. When a device that inverts an animal is required by some religious leaders, it

3940 should have adjustable sides that support the animal and prevent its body from slipping,

3941 twisting, or falling during inversion. Inversion onto the back facilitates the downward

3942 cutting stroke. Upright or sideways (lying on the side) restraint may be less aversive than

3943 full inversion. Full inversion was more aversive to sheep than being held in an upright

3944 position (Hutson, 1985). Sheep can be easily trained to voluntarily enter a tilt table which

3945 tilted them sideways (Grandin, 1989).

3946 It is important to minimize the time that an animal is held firmly by a head

3947 restraint. Head restraint using a mechanized device that tightly holds the head is more

3948 aversive than body restraint (Grandin, 1992). Cattle that were held firmly in a head

3949 restraint often struggle more than cattle held in a body restraint with no head restraint

3950 (Grandin, 1992). Resistance to the head restraint occurs after approximately 30 seconds

3951 therefore it is important to perform the throat-cut before struggling or vocalization

3952 begins. Restraint devices should be equipped with pressure limiting devices to prevent

3953 excessive pressure from being applied which then causes either struggling or vocalization

3954 (Grandin, 1992). The percentage of cattle vocalizing (mooing or bellowing) either while

3955 in a restraint device or while entering it should be 5% or less (Grandin, 2010, 2012b).

3956 Restraint devices should not cause animals to struggle or vocalize (OIE, 2008). For

3957 poultry stress during shackling can be reduced by subdued lighting. Wing flapping can

3958 be reduced by installing vertical pieces of conveyor belting with a smooth surface for the

3959 breasts of the shackled birds to rub on. A possible future method to reduce bird stress

3960 while in shackles is the incorporation of a moving horizontal conveyor that supports the

171

3961 bird’s body (Lines et al., 2011). A Dutch poultry plant recently installed a system where

3962 each shackled chicken has its body supported in a plastic holder (Smith, 2012). In small

3963 plants, chickens can be either held by a person in an upright position for the throat cut

3964 and then placed in a bleeding cone, or placed on the shackle immediately after the throat

3965 cut.

3966 Step 7—Performing the Throat Cut

3967 There are three basic ways that religious slaughter is performed. 1) Preslaughter

3968 stunning before the throat cut with either a captive bolt or electrical stunning, 2)

3969 Immediate post-cut stunning with a captive bolt or 3) Slaughter without stunning

3970 (traditional hand slaughter). Some religious authorities who supervise either kosher

3971 (Jewish) or halal (Muslim) religious slaughter will allow either preslaughter or immediate

3972 post-slaughter stunning. For halal slaughter electrical head only stunning is used in many

3973 large cattle and sheep plants in New Zealand, Australia, and the United Kingdom. Head

3974 only electrical stunning is acceptable to many Muslim religious authorities because it is

3975 fully reversible and induces temporary unconsciousness (see Techniques: Electric). If

3976 preslaughter stunning is done, there will be no animal welfare concerns about the throat

3977 cut in a conscious animal. Since most preslaughter stunning methods that are approved

3978 for religious slaughter produce a lighter reversible stun, greater attention will be required

3979 to the details of procedures to insure that the animals or birds are and remain unconscious

3980 during the throat cut. An effective reversible pre-cut stun in sheep can be easily achieved

3981 with 1.25 amps to 2 amps at a frequency range of 50 to 400 hz. When the stunner was

3982 applied to the head for 1.5 sec. at 300 hz, it produced a clear tonic rigid phase followed

3983 by a clonic kicking phase representative of an epileptic seizure (T. Grandin, personal

172

3984 communication, 2012). This pattern is an indicator that it produced unconsciousness. A

3985 modified New Zealand head to back stunner with the rear body electrode removed

3986 worked well because the design of the handle facilitated positioning of the stunner on the

3987 sheep’s head. In poultry a very light reversible electrical water bath stun is done. The

3988 above stunning methods are acceptable to a number of halal certifiers. Some halal

3989 certifiers will accept non-penetrating captive bolt. Some religious communities will

3990 accept immediate post-cut stunning and others require slaughter without stunning

3991 (traditional hand slaughter). Stunning methods are covered in the Techniques chapter of

3992 these Guidelines.

3993 Detections of Problems

3994 The greatest welfare concerns may occur during traditional religious hand

3995 slaughter. The two main issues are: 1) does cutting the throat of a conscious animal

3996 cause pain? And; 2) what is the maximum appropriate time that is required for the

3997 animal to become unconscious after a properly done throat cut? The throat cut done

3998 during both kosher and halal slaughter simultaneously severs both carotid arteries and

3999 jugular veins and the trachea. For halal slaughter, a sharp knife is required. Kosher

4000 slaughter has more strict specifications for how the cut is performed and the design and

4001 sharpening of the knife (Levinger, 1995; Epstein, 1948). A kosher slaughter knife is long

4002 enough to span the full width of the neck (i.e., double the width of the neck) and is

4003 sharpened on a whetstone. Before and after each animal is cut, the knife is checked for

4004 nicks that could cause pain (Levinger, 1995; Epstein, 1948). Any nick in the knife makes

4005 the animal non-kosher, so there is a strong incentive to keep the knife razor-sharp and

4006 nick free.

173

4007 Painfulness of the Cut

4008 Researchers have reported that cutting the throat of 109 to 107 kg veal calves with

4009 a knife that was 24.5 cm long caused pain comparable to dehorning (Gibson et al.,

4010 2009a,b). The knife may have been too short to fully span the throat and it had been

4011 sharpened on a mechanical grinder. A grinder may create nicks on the blade and may not

4012 be comparable to a knife sharpened on a whetstone. Slaughter without stunning of cattle

4013 with a knife that is too short will result in violent struggling because the tip makes

4014 gouging cuts in the wound (Grandin, 1994). One of the rules of kosher slaughter is that

4015 the incision must remain open during the cut (Epstein, 1943; Levinger, 1995). When the

4016 wound is allowed to close back over the knife, cattle will violently struggle (Grandin and

4017 Regenstein, 1994). When an animal is restrained in a comfortable upright position, it

4018 becomes possible to observe how the animal reacts to the throat cut. When a kosher

4019 knife was used by a skilled slaughter man (shochet) there was little behavioral reaction in

4020 cattle during the cut (Grandin, 1994; Grandin and Regenstein, 1994). In calves, there has

4021 been a similar observation (Bager et al., 1992). People invading the animal’s flight zone

4022 by getting near to the animal’s face caused a bigger reaction (Grandin, 1994). An eartag

4023 punch has also caused a bigger reaction than a good kosher cut (Grandin and Regenstein,

4024 1994). Most chickens slaughtered by shechita exhibited no physical response to the cut

4025 and they lost the ability to stand and eye reflexes at 12 to 15 seconds (Barnett et al.,

4026 2007).

4027 Time to Lose Consciousness

4028 Unconsciousness, as defined in the General Introduction of these Guidelines, is

4029 the loss of individual awareness that occurs when the brains ability to integrate

174

4030 information is blocked or disrupted. Before invasive dressing begins all signs of brain

4031 stem function such as the corneal reflex must be abolished by bleeding. Sheep will lose

4032 consciousness as determined by their EEG more quickly than cattle due to differences in

4033 the anatomy of the blood vessels that supply the brain (Baldwin and Bell, 1963a,b). In

4034 cattle, when the carotid arteries are severed, the brain can still receive blood from the

4035 vertebral arteries (Baldwin and Bell, 1963a,b). After the cut, sheep will become

4036 unconscious and lose posture and no longer be able to stand within 2 to 14 sec, while

4037 most cattle will lose consciousness and no longer be able to stand within 17 to 85 seconds

4038 (Blackmore et al., 1983; Blackmore, 1984; Nangeroni and Kennett, 1983; Newhook and

4039 Blackmore, 1982; Schulz et al., 1978; Daly et al., 1988; Gregory and Wotton, 1984). In

4040 the above studies, time to onset of unconsciousness was measured by either EEG or loss

4041 of the ability to stand. Allowing the wound to close up after a transverse halal throat cut

4042 with a 20 cm long knife may delay onset of unconsciousness. EEG measurements on

4043 sheep indicated consciousness could last 60 seconds (Rodriguez, et al., 2012). In a study

4044 where a rotating box was used to invert veal calves onto their backs, unconsciousness

4045 was measured by EEG. It occurred at an average of 80 seconds (Lambooij et al., 2011).

4046 In sheep, unconsciousness as measured by time to eye rotation was 15 seconds (Cranley,

4047 2012).

4048 There is a large amount of biological variability and a few cattle, calves or sheep

4049 have extended periods of sensibility (greater than 4 minutes; Gregory et al., 2012a;

4050 Gregory and Wotton, 1984). If the animals can stand and walk they are definitely

4051 conscious. In sheep the corneal reflexes, which are a brain stem reflex, may be present for

4052 up to 65 sec after the cut (Cranley, 2012). In veal calves, corneal reflexes were still

175

4053 present at 135 + 57 sec after the throat cut (Lambooij et al., 2011). The methods section

4054 of Lambooij et al. (2011) did not describe the type of knife. However, this study was

4055 done in a slaughter plant that performed halal slaughter. Corneal reflexes can also occur

4056 in electrically or CO2 stunned animals where other indicators of return to consciousness,

4057 such as the righting reflex, rhythmic breathing, and eye tracking are absent (Vogel et al.,

4058 2011). Corneal reflexes occur during a state of surgical anesthesia (Rumpl et al., 1982)

4059 or when visual and somatosensory evoked potentials are abolished (Anil and McKinstry,

4060 1991). One of the best indicators for determining onset of unconsciousness is the loss of

4061 the ability to stand and walk. In cattle, a major cause of prolonged periods of

4062 consciousness after the throat cut is sealing off of the ends of the severed arteries (false

4063 aneurysms) (Gregory et al., 2008a). This problem does not occur in sheep.

4064 Aspiration of Blood

4065 Another welfare concern is aspiration of blood into the trachea and lungs after the

4066 cut. When cattle are held in a well-designed upright restraint, 36% (for kosher) and 69%

4067 (for halal) aspirated blood (Gregory et al., 2008b). It is likely that in a rotating box where

4068 the animal is held on its back, aspiration of blood will be higher (T. Grandin, personal

4069 communication, 2005).

4070 Corrective Action for Problems

4071 To reduce painfulness of the act, a knife that is long enough to span the neck

4072 where the tip will remain outside the neck during the cut should be used (OIE, 2008). It

4073 is also essential that the knife be extremely sharp and the use of a whetstone is

4074 recommended. A good method for testing a knife for sharpness is the paper test. To

4075 perform this test a single sheet of standard (A4) 8 ½ by 11 inch computer printer paper is

176

4076 dangled in a vertical position by being held by a thumb and forefinger by one corner. A

4077 dry knife held in the other hand should be able to start cutting at the edge of the paper and

4078 slice it in half. This method can eliminate the worst dull knives, but it may not detect

4079 sharp knives with nicks.

4080 It is also essential to not allow the wound to close back over the knife during the

4081 cut. To prevent sealing off of the arteries in cattle, the cut should be angled so it is close

4082 to the first cervical vertebrae (C1) position (Gregory et al., 2012a,b) as long as such a cut

4083 is accepted by the religious authorities. This will also cut a sensory nerve, which may

4084 prevent the cattle from experiencing distressful sensory sensations from aspirating blood

4085 (Gregory et al., 2012a,b). The cut should be located posterior to the larynx and angled

4086 towards the C1 position.

4087 Before invasive dressing procedures such as skinning or leg removal are started,

4088 the corneal reflexes must be absent. Even though an animal showing only a corneal

4089 reflex is unconsciousness, to provide a good margin of safety, it should be absent before

4090 dressing procedures start. Absence of the corneal reflex and complete unconsciousness

4091 before dressing procedures are started is a best practice for all slaughter plants that

4092 conduct both conventional slaughter and religious slaughter.

4093 Auditing Religious Slaughter to Improve Animal Welfare for both Kosher and Halal

4094 Slaughter of Cattle, Sheep or Goats

4095 The following audit methods are recommended to maintain an acceptable level of

4096 animal welfare when religious slaughter is performed by cutting of the neck.

4097 1. Calm animals will lose sensibility quicker. Follow all procedures for handling

4098 that are in other parts of this document (Grandin 1994, 1992).

177

4099 2. Conduct collapse time scoring. When the best methods are employed, 90% of

4100 the cattle will collapse and lose the ability to stand within 30 seconds (Erika

4101 Voogd, personal communication, 2009). Researchers in Europe reported a

4102 similar result when they used a well-designed upright restraint device

4103 (Gregory et al., 2010). In a rotating box, collapse time scoring is impossible

4104 because the animal is on its back. Alternative measures for determining onset

4105 of unconsciousness are time until eye rotation and the amount of time to

4106 abolish the presence of natural blinking such as seen with a live animal in the

4107 yards (lairage). Natural blinking must not be confused with the corneal reflex.

4108 To evaluate natural blinking (menace reflex), a hand is waved within 4 inches

4109 (10 cm) of the eye without touching it. A natural blink occurs if the eye does

4110 a full cycle of closing and then re-opening. Omit scoring of time to

4111 insensibility if pre- or post-cut stunning is used.

4112 3. The vocalization score should be 5% or less for cattle (Grandin, 2010, 2012a).

4113 Score on a per animal basis, as a silent animal or a vocalizer (mooing or

4114 bellowing). All cattle that vocalize inside the restraint device are scored. A

4115 bovine is also scored as a vocalizer if it vocalizes in direct response to being

4116 moved by either a person, electric prod, or a mechanical device into the

4117 restraint device. Do not use vocalization scoring for sheep. Standards for

4118 vocalization scoring of goats will need to be developed.

4119 4. In all species score restraint methods for the percentage of animals that

4120 actively struggle.

178

4121 5. The percentage of animals (all species) that fall down in the chute (race)

4122 leading up to the restraint device or fall before the throat cut in the restraint

4123 device should be 1% or less. This is the same as conventional slaughter.

4124 Restraint devices that are designed to make an animal fall are unacceptable

4125 and result in an automatic audit failure. Rotating boxes must fully support the

4126 body and the animal’s body should not shift position or fall when the box is

4127 rotated.

4128 6. Electric prod use must be minimized. Score prod use using the same criteria

4129 as conventional slaughter.

4130 7. Perform the cut quickly, preferably within 10 seconds after the head is fully

4131 restrained. Omit this measure if preslaughter stunning is used.

4132 8. Reduce the pressure applied by the head holders (but do not remove it), rear

4133 pusher gates and other devices immediately after the cut to promote rapid

4134 bleed out.

4135 9. Corneal reflexes, rhythmic breathing and all other signs of return to sensibility

4136 must be absent before invasive dressing procedures such as skinning, leg

4137 removal or dehorning is started. This is a requirement for all methods of

4138 slaughter both conventional and religious to be absolutely sure that the animal

4139 is completely insensible.

4140 10. Do not use stressful methods of restraint for mammals, such as shackling and

4141 hoisting by suspension by one or more limbs, shackling and dragging by one

4142 or more limbs, trip floor boxes that are designed to make animals fall, leg

4143 clamping boxes or other similar devices.

179

4144 Auditing Religious Slaughter to Improve Animal Welfare for both Kosher

4145 and Halal Slaughter of Chickens, Turkeys, and other Poultry

4146 1. If stunning is used, audit and monitor the percentage of birds that are effectively

4147 stunned the same as used for conventional slaughter.

4148 2. Score the performance of shacklers for faults such as one-legged shackling the

4149 same as used for conventional slaughter.

4150 3. There should be 0% uncut red skinned birds that emerge from the defeathering

4151 machine. This is an indicator that a bird entered the scalder alive. This measure

4152 is the same as used for conventional slaughter.

4153 4. Score the percentage of birds that wing flap after restraint. In a well-designed

4154 shackle line with a breast rub conveyor, the percentage should be very low –

4155 under 1%. If birds are hand held, wing flapping can also be scored.

4156 The Importance of Measurement

4157 By routinely measuring the performance of religious slaughter procedures, the

4158 standards for such slaughter are kept high. Measuring collapse times for unconsciousness

4159 or other indicators such as time to eye roll back or the absence of natural blinking will

4160 enable both plant personnel and religious slaughter personnel to improve their

4161 procedures.

180

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