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World Journal of Biology and Medical Sciences Published by Society for Advancement of Science® ISSN 2349-0063 (Online/Electronic) Volume 2, Issue- 4, 115-125, October to December, 2015

WJBMS 2/04/51/2015 All rights reserved www.sasjournals.com A Double Blind Peer Reviewed Journal [email protected]/[email protected] REVIEW ARTICLE Received: 19/08/2015 Revised: 07/09/2015 Accepted: 08/09/2015

An Overview on Fever in Dairy Cattle in and Around West Shoa Erkihun Tadesse and *Lingerih Belete Addis Ababa University, College of Veterinary Medicine and Agriculture, P.O. BOX: 34, Debre Zeit Ethiopia *Hawassa University, Faculty of Veterinary Medicine and Agriculture, Hawassa, Ethiopia

ABSTRACT Milk fever is a condition of older, third to sixth , high producing dairy cows. It is associated with parturition, usually within 72 hours of giving birth. Because of the high volume of milk produced during this time and subsequent demand for , these cows often develop hypocalcaemia, or abnormally low levels of calcium in the blood. Since calcium is required for the release of acetylcholine at the neuromuscular junction, affected animals will begin to experience muscle weakness. As this hypocalcaemia worsens, the cow will become too weak to stand and will eventually become comatose over a matter of hours. Parturient paresis is treated intravenously with calcium borogluconate. Affected cows have an excellent prognosis if treated early and properly. However, the worse the symptoms, the worse the prognosis tends to be. Any preventive measure must be aimed at eliminating the precipitous fall in blood calcium at parturition. For assessing economic losses caused by milk fever cost of medicines, cost of additional labour utilized, loss due to reduction in milk output, cost of animals dead and culled should be considered. Generally, the dairy profitability is directly related to the level of milk production. Keywords: Calcium Borogluconate, Dairy Cattle, Milk Fever and Parturient Paresis.

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INTRODUCTION considerable importance for dairy cow Among domestic farm animals, the welfare and economy. Although metabolic diseases achieve their greatest treatment with intravenous infusion of importance in dairy cows. The high calcium salt solutions cure most clinical producing dairy cows always verge on cases of hypocalcaemia (Curtis et al., abnormality because the breeding and 1994). It has been proposed that a specific feeding of dairy cattle for high milk yield is control program is relevant when the etiologically related to the diseases of incidence of milk fever increases to above metabolism so common in these animals. 10% among high risk cows that is cows In dairy cows, the incidence of metabolic entering third or later . So diseases is highest in the period prevention of milk fever is economically commencing at calving and extending important to the dairy farmer because of until the peak of lactation is reached, and reduced production loss, death loss, and this susceptibility appears to be related to veterinary costs associated with clinical the extremely high turnover of fluids, salts cases of milk fever (Bradford, 1996). and soluble organic materials during the Therefore, the objectives of this seminar early part of lactation (Corohn, 1998). paper are: Inadequate blood calcium concentrations  To give an overview on milk fever in can cause a cow to lose the ability to rise dairy cattle and to her feet as calcium is necessary for  To indicate appropriate prevention nerve and muscle function. These results and control methods of milk fever in the metabolic disease known as milk in dairy cattle. fever, although it is more properly termed GENERAL ACCOUNTS ON MILK FEVER IN hypocalcaemia or parturient paresis, as an DAIRY COWS elevated body temperature is not typically Milk fever is a metabolic disturbance observed. It is a common metabolic usually of dairy cows, characterized by disorder in dairy cattle that generally reduced blood calcium levels. It is most affects older, high producing cows. The common in the first few days of lactation, lowered blood calcium in milk fever is due usually within 72 hours, when the demand to the failure of the blood calcium of calcium for milk production exceeds regulatory mechanism to mobilize calcium the body’s ability to mobilize calcium from the tissue reserves rapidly enough to reserves. Fever is a misnomer, as body equal the withdrawal of calcium from the temperature during the disease is usually blood into the udder secretions. The below normal. Low blood calcium level is the primary interferes with muscle function regulator of blood calcium, its failure in throughout the body, causing general milk fever is caused by either parathyroid weakness, depression and death. It is inadequacy which resulting in the lack of more common in older dairy cows which sufficient hormone secretion, or by the have reduced ability to mobilize calcium presence of some metabolic condition in from bone and in high milk producing the tissues at parturition that renders the breeds (Huntjens, 1995). parathyroid hormone temporarily inactive Etiology (Radostits et al.,2007). Deficiency of calcium ion in the tissue There are risk factors for the precipitation fluids and fall in serum calcium level at of milk fever in the dairy cows to occur calving due to the onset of lactation is the including age, breed, body condition and major biochemical defect in parturient dietary factors. Milk fever is a disease of paresis. Serum calcium level falls in all

116 adult cows at calving (Radostits et al., adaptation mechanism is directly related 2007). The delay in the operation of to the efficiency of intestinal absorption calcium homeostatic mechanisms is vital of calcium, which decreases with in causing milk fever. Calcium increasing age. Most cases occur in homeostasis is affected by three factors animals older than five years of age. This and variations in one or more of them are is as a result of increasing milk production instrumental in causing the disease in any with age and decreasing efficiency of individual. These are excessive loss of dietary calcium absorption and bone calcium in the colostrums beyond the resorption (Bradford, 1996). capacity of absorption from the intestines Breed: There are differences in and mobilization from the bones to susceptibility of milk fever among breeds. replace, impairment of absorption of There is a genetic predisposition of cows calcium from the intestine at parturition to milk fever and this is well recognized in and insufficiency of mobilization of certain breeds of high producing Jersey calcium from storage in the skeleton, and other breeds. This is associated with which could arise because of parathyroid higher milk production per unit of body insufficiency since the gland is relatively weight, reduction of intestinal vitamin D3 quiescent due to the decreased calcium receptors as Jersey’s age, and a higher and phosphorus metabolism of the dry than normal production of parathyroid period (Mulligan et al., 2006). hormone related proteins by the Epidemiology , which increases calcium Parturient paresis is a disease of high transport from bone to milk (Colls, 1990). producing dairy cattle. It is estimated that Body condition score: A high BCS 3% to 8% of cows are affected by this increases the risk of milk fever. Dairy cows disease with some herds having that are over conditioned at calving are up prevalence as high as 25% to 30%. to four times more likely to develop milk Parturient paresis occurs before calving, fever (Ostergaard et al., 2003). This is due but most cases occur within the first 48 to dairy cows with higher BCS at calving hours following calving (Goff, 2004). have a higher calcium output in milk, The risk factors for hypocalcaemia are making them more prone to milk fever grouped into intrinsic risk factors, which and over conditioned cows take small are associated within the animal itself, amount of calcium this is caused by and extrinsic risk factors, which are reduced appetite in the critical period outside of the animal’s body (Peterson around calving which predisposes them to and Beede, 2002). the development of hypocalcaemia (Harris Age: The hypocalcaemia at calving is age et al., 1999). related and most marked in cows from Dietary factors: Diets providing dry cows third to seventh parturition; it is a high daily intake of calcium are infrequent at the first parturition. This is associated with an increased incidence of because while some degree of parturient paresis. At this level the hypocalcaemia occurs during the first few maintenance requirement of calcium can days of lactation, they are able to adapt be met predominantly by passive rapidly to the high demands of calcium for absorption since active absorption of lactation. With increasing age, this dietary calcium and bone resorption are adaptation process is decreased and then suppressed. Cows in this condition results in moderate to severe are not able to quickly replace plasma hypocalcaemia in most adult cows. The

117 calcium lost in milk and become severely with clinical hypocalcaemia have higher hypocalcaemic (Boda and Cole, 2003). levels of PTH and 1, 25 dihydroxy vitamin Diets high in phosphorus at the onset of D3 (Harris, 2002). Hypocalcaemia affects lactation also increase the incidence of muscular contraction mainly in three milk fever and the severity of ways. Firstly, calcium has a membrane hypocalcaemia. High dietary level of stabilizing effect on the peripheral nerves. phosphorus decreases the production of Hyperesthesia and mild tetany seen in 1, 25 dihydroxy vitamin D3 and thus early stages of milk fever are due to lack reduces the intestinal calcium absorption of nerve cell membrane stabilization. mechanisms (Horst, 1996). Pre-partum Secondly, calcium is required for the diets high in cations like sodium and release of acetylcholine at the potassium are associated with an neuromuscular junction. The inability to increased incidence of milk fever while release acetylcholine, due to diets of high in anion, especially chlorides hypocalcaemia causes paralysis by and sulfides are associated with blocking the transmission of nerve decreased incidence of the disease. The impulse to the muscle fibers. Thirdly, addition of anions to the diet of dairy calcium is directly required by muscle cells cows prior to parturition effectively for contraction. Paralysis of various reduced the incidence of milk fever by muscle types results in the clinical signs of inducing a metabolic acidosis, which parturient paresis (Iggo, 1994). There is facilitates bone resorption of calcium decreased contractility of cardiac muscle (Bradford, 1996). and lowered stroke volume cause Pathophysiology reduction in arterial blood. Then this During the dry period, calcium demand is reduced peripheral perfusion resulted in relatively low. Hence, intestinal hypothermia and depression of absorption and bone resorption of consciousness. In addition, there is GIT calcium is relatively inactive during this stasis and bloat resulted from smooth time. The onset of lactation at the time of muscle atony. Hypophosphatemia is seen parturition results in sudden loss of in cows suffering from milk fever. This is calcium through milk. When the calcium as the result of phosphorus loss in milk, homeostatic mechanism is unable to meet inadequate feed intake around the time the demand of calcium for milk of parturition, and increase renal and production, hypocalcaemia or low blood salivary excretion of phosphate caused by calcium level occurs (Ramberg et al., a high circulating level of PTH. 1994). Hyperglycemia associated with milk fever This fall in blood calcium level stimulates is caused by increased glucocorticoid the calcium homeostatic mechanism to release and gluconeogenesis caused by improve intestinal calcium absorption and stress. There is an occurrence of increase bone resorption. Approximately hypermagnesemia in cows suffering from 24 hours of elevated 1, 25 dihydroxy parturient paresis due to the effect of PTH vitamin D3 is required to improve by increasing tubular resorption by the intestinal transport of calcium and an (Bartlet et al., 1990). increased rate of bone resorption requires Clinical sign 48 hours of PTH stimulation. When these Based on the degree of hypocalcaemia compensatory mechanisms are and time of occurrence the clinical sign of prolonged, clinical hypocalcaemia or milk milk fever are grouped in to three stages fever develops. Consequently, most cows (Aiello et al., 1998).

118 Stage I: Milk fever often goes unobserved Stage II (Sternal recumbency): The clinical because of its short duration less than one signs of stage II milk fever can last from 1 hour. This are seen when animals are in to 12 hours. This is frequently seen with standing position. Signs observed during lateral kink or S-shape neck curvature in this stage include excitability, which the cow tends to lie with her head nervousness, hypersensitivity, weakness, tucked into her flank. Her temperature is and hyperesthesia. There is smooth subnormal, her muzzle dry, coldness of muscle paralysis that results in an inability skin and extremities. The heart rate will to swallow, consequently in appetance be rapid exceeding 100 beats per minute, and low thirst, ruminal stasis with the gastrointestinal atony predisposes to passing of small amounts of dry faeces, constipation and mild bloating. She and the suspension of urination (Bradford, exhibits in coordination when walking. 1996). (Aiello et al., 1998).

Figure 1. Cow in sternal recumbency. Source: Kimura et al., 2006

Stage III (Lateral recumbency): It is nearly inaudible and the heart rate characterized by inability to stand and a increases to 120 beats per minute or progressive loss of consciousness leading more. Cows will not survive for more than to coma. There is a marked fall in a few hours without treatment in this temperature and heart sounds become stage (Radostits et al., 2007).

Figure 2. Cow in lateral recumbency. Source: Kimura et al., 2006

119 DIAGNOSIS AND TREATMENT 2 to 3 days after onset of initial signs is Diagnosis seen in hypoglycemia but during Diagnosis is based on the cow’s history, hypocalcaemia rapid recumbency over 3 clinical signs and response to intravenous to 4 hours with sternal recumbency. In calcium borogluconate solution. The response to treatment, in hypoglycemia occurrence of paresis and depression of there is no response to hypocalcaemia consciousness in cows that have recently treatment dose rates and usually poor given birth to young are diagnostic signs and slow doses of glucose or energy. for the disease. The diagnosis is confirmed During hypocalcaemia response is rapid by laboratory examination of the blood and good recovery is seen after injection and rapid characteristic response to of treatment doses of commercial calcium treatment with calcium borogluconate. doses The most notable changes occurring in the (http://www2.dpi.qld.gov.au/sheep/1018 blood are a decrease in blood calcium and 2-html). blood phosphorus levels and an increase Treatment in blood magnesium levels (Radostits et Treatment of the disease usually consists al., 2007). of intravenous or subcutaneous injection Cows with serum calcium lower than 7.5 of calcium borogluconate at dose rate of mg/dl are as considered as 400 to 800 ml of a 20% solution. Early hypocalcaemic. Animals with serum intravenous calcium borogluconate is the calcium level of 5.5 to 7.5 mg/dl show sign treatment of choice for severely affected of stage I hypocalcaemia. Stage II patients. The solution must be given hypocalcaemia seen with calcium levels of slowly because rapid calcium infusion may 3.5 to 6.5 mg/dl and stage III seen when result in cardiac arrest. Concurrent use of calcium concentration falls to as low as 2 subcutaneous calcium borogluconate may mg/dl. Prolonged recumbency results in prevent recurrence, by slow release of ischemic muscle necrosis and increases in biologically available calcium from the the serum muscle enzymes CPK and AST. tissues into the bloodstream (Anderson et The value CPK normally ranges between al., 1998). 105 to 409 IU/L, a value greater than 1000 Patients with mild signs are appropriately IU/L indicates severe muscle damage from treated with subcutaneous or oral calcium being down, and AST levels over 500 IU/L products. The response to properly indicates severe muscle damage administered calcium therapy is quite (Bradford, 1996). characteristic. Cows generally rise within For an accurate diagnosis of milk fever, one hour. The cow’s symptoms will differential diagnosis is important to appear to reverse themselves as they had determine milk fever from other disorders previously progressed. The laterally with similar clinical sign like hypoglycemia. recumbent cow will sit up to sternal Typical signs and indications that position, and then it will often begin to differentiate milk fever from have over its body. As all bodily hypoglycemia includes in hypocalcaemia functions affected by hypocalcaemia there is rapid progression of the disease begin to reverse, the affected animal may with death after 6 to 12 hours, but in urinate, and then begin the wobbly effort hypoglycemia there is slow progression of to rise. Repeated treatment may be the disease with death 5 to 7 days. necessary within 12 hours if the cow is still Elevation of the chin (star gazing posture) unable to rise. Approximately 75% of cows with slow progression to recumbency over

120 with milk fever respond to only one immunity in milk fever cows when treatment and recover (Blowey, 1995). compared with normal cows. Cortisol is an The prognosis is excellent if cows are important component of the suppressed treated early and properly. As the immunity experienced by peri parturient symptoms worsen so does the prognosis. dairy cattle since milk fever cause an Cows down for more than 48 hours may increase in the normal cortisol response at develop muscle inflammation and never parturition (Goff, 2004). be able to stand. Relapse is relatively Milk fever and GIT function: There is a common unless longer acting reduction in the motility of rumen and supplements are added to the treatment abomasum in clinically hypocalcaemic plan. Older cows and cows displaying cows. This reduction in ruminal and signs prior to calving have the highest risk abomasal motility will likely cause a for relapse (Oetzel, 1988). reduction in feed intake (Jorgensen et al., ECONOMIC SIGNIFICANCE 2001). Milk fever in dairy production reduces the Milk fever, dystocia and uterine prolapse: efficiency with which inputs are converted Loss of uterine muscle tone due to into out puts (milk yield and fertility) and in cows suffering from milk hence result in decreased overall fever is a major cause of uterine prolapse productivity. There are costs directly (Buxton et al., 1997). Cows with milk fever associated with the disease including the are developing dystocia 6 times more cost of veterinary treatments and the than that of normal cows. This is because herdsman’s time spent dealing with the of a reduced ability of smooth and skeletal affected animals. The indirect cost of the muscle contraction causes for cow’s long milk fever is due to increased risk to period in labour, which predisposes to associated health problems, increased risk dystocia (Correa et al., 1993). of calving problems, and the possible risk PREVENTION AND CONTROL of fatality (Kossaibati and Esslemont, A specific control program is relevant 1997). Milk fever predisposes cows to when the incidence of milk fever increases many potential health problems to above 10% among high-risk cows that is (Brosberry and Dabson, 1989). cows entering third or later lactations. Milk fever and fertility: Milk fever results Several milk fever control principles and in reduced fertility in dairy cows due to its factors are applied in commercial dairy effect on uterine muscle function, slower farms today. These includes oral uterine involution and reduced blood flow drenching around calving with a to the ovaries. There are also indirect supplement of easily absorbed calcium, effects of milk fever on fertility, which is the feeding of acidifying rations by anionic mediated through dystocia, endometritis salt supplementation during the last and retained placenta (Jonsson and weeks of pregnancy, feeding low calcium Daniel, 1997). rations during the last weeks of pregnancy Milk fever and mastitis: Cows that have and management practices such as body suffered from clinical milk fever are 8 condition control and shortening the dry times more likely to develop mastitis than period (Radostits et al., 2007). normal cows. This phenomenon is mainly Oral calcium drenching around calving due to a reduction in smooth muscle Preparations containing easily absorbed function at the teat sphincter and hence calcium salt such as calcium chloride, an easy routine for infection after milking providing 40 to 50 g of calcium per dose and an exacerbated suppression of can be used. Most documented

121 preventive programs involve intestinal tract, rendering the calcium administration of 3 to 4 doses distributed homeostatic mechanisms relatively evenly during the period from 12 to 24 inactive (Boxton et al., 1997). hours before calving to 24 hours after By feeding low calcium diets in the dry calving (Agger et al., 1997). period, the calcium homeostatic Oral calcium treatment presumably mechanisms are activated before calving, increases luminal calcium concentration and the cow is thus capable of absorbing favouring passive transport of calcium calcium more efficiently from the into the extra cellular fluids. The capacity intestinal tract as well as drawing calcium of the passive transport of calcium is in from the bone around the time of calving principle unlimited and independent of (Leclerc and Block, 1999). stimulation by 1, 25 dihydroxy vitamin D3. A high in dietary phosphorus suppressed Increasing the amount and the number of vitamin D hydroxylation in the kidney, drenching with calcium compounds thereby indirectly reducing calcium providing free calcium ions therefore absorption. The reduced intestinal quickly increases the amount of calcium calcium absorption elicited an increase in ions absorbed into the bloodstream (Goff the PTH level, which in turn aided in the and Horst, 1993). prevention of milk fever by increasing the Feeding of acidifying rations (dietary amount of calcium in the blood by tubular cation-anion difference) absorption of calcium from the intestine It is now widely accepted that the and resorption from the bone. In addition, homeostatic mechanisms that result in low dietary phosphorus is helpful in milk fever prevention work more preventing milk fever, when the level of efficiently when DCAB is negative. The dietary calcium is high. Since the low most common strategy employed to dietary phosphorus results in an increase achieve this negative DCAB is the addition formation of 1, 25 dihydroxy vitamin D3, of anionic salts to the diet of pre calving which in turn increases the efficiency of cattle (Goff, 2004). This is most efficiently intestinal absorption of calcium and achieved by the ingestion of rations phosphorus (Allen and Davies, 1995). having a surplus of acidifying anions. The Management practices effect is mediated via an enhancement of Body condition score management the stimulatory effects of PTH. Bone Over conditioned cows at calving have a resorption may be involved and an higher incidence of milk fever and other increase in the apparent calcium diseases post partum. Achieving the absorption from the digestive tract correct BCS at calving and drying off is (Jorgenson et al., 2001). critical for the prevention of milk fever Low calcium intake and low (Ostergaard et al., 2003). calcium/phosphorus in late pregnancy Shortening of the dry period This principle is based on preventing Cows with long non-lactating periods are calcium homeostatic mechanisms from predisposed to becoming excessively fat, becoming quiescent during the dry period since cows do not regulate intake (Oetzel, 1996). The calcium demand of the according to their physiological dry cow is very limited in the last two requirements. Besides obesity, a long dry months of pregnancy. When calcium period may result in a more quiescent intake exceeds the requirements, the calcium homeostasis (Davicco et al., calcium demand can be meet almost 1992). entirely by passive diffusion from the

122 Magnesium supplementation management and shortening the dry Ensuring adequate magnesium period are also critical for the prevention supplementation is vital for the of the disease. prevention of milk fever. Magnesium Based on the above conclusion the plays a very important role in calcium following recommendations are metabolism; it is a key intermediate in the forwarded: resorption of calcium from bone by  Avoid over fattening by either parathyroid hormone. In a recent review, reducing the energy increasing magnesium supplementation concentration of the ration or has the greatest influence among dietary restricting the intake during the strategies for the prevention of milk fever. pre partum period. Therefore, dietary magnesium  Implementation of a well concentration for pregnant dairy cattle monitored feeding strategy for should be in the region of 0.4% of dry dairy cattle especially during the matter (Lean et al., 2006). pre partum period.  Education of dairy farmers to CONCLUSION AND RECOMMENDATIONS make frequent observations of Milk fever or parturient paresis is a cows prone to milk fever from 48 common metabolic disturbance in dairy hours before to 72 hours after cows resulting from hypocalcaemia that parturition for evidence of milk occurs in older, third to sixth lactation, fever. high producing dairy cows that are near  At calving, the cow should receive calving or have recently calved. It is an oral dose of a calcium salt in a mainly characterized by progressive gel, as set out later, followed by a muscle weakness and depression that diet with high calcium content. progresses into coma if not treated  Further study should be promptly. Calving causes a high volume of conducted on the epidemiology milk production and with it, a high of the disease and its economic demand for calcium from the cow’s body. impact in dairy farms. If the body is unable to respond quickly to this demand, the cow develops ACKNOWLEDEGMENTS hypocalcaemia. Hypocalcaemic cows will I would like to thank my advisor, Dr. begin trembling and will no longer be able Dereje Bantigegn, in assisting me to to stand. Subsequently the cow becomes prepare this paper. recumbent, first in the sternal position, My special thanks also go to my best and then laterally. Parturient paresis is friends especially Aysheshim M. (editor) favorable to early treatment with and Kassahun B., who are helping me intravenous calcium supplementation. while I am preparing this paper. Economically, it reduces milk yield and fertility. There are also losses due to cost REFERENCES of treatment, herdsman’s time spent for Agger, N., Katholm, J. and Lomborg, K. dealing the diseased animal and increase (1997). A pharmacokinetic study of the risk of associated health problems. As plasma calcium concentration in dairy with most illnesses, prevention is the key. cows following four oral administrations Dietary calcium levels must be low in the at 12 hour intervals around calving of a weeks leading up to calving. Management calcium chloride paste formulation. The practices like body condition score Bovine Proceedings, 30: 72-75.

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Corresponding author: Erkihun Tadesse, Addis Ababa University, College of Veterinary Medicine and Agriculture, P.O. BOX: 34, Debre Zeit Ethiopia. Email: [email protected]

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