DIVISION OF AGRICULTURE R E S E A R C H & E X T E N S I O N University of Arkansas System Agriculture and Natural Resources FSA3112

Beef Performance Glossary

Tom R. Troxel – A cooperative business Alliancearrangement in which a cattle producer Professor and Associate A – A swollen, inflamed area in arranges for the retained ownership Abscessbody tissue in which pus gathers. Department Head ­ Animal and/or contract sale of his/her animals Science – A measure of reliability before they actually are produced. Accuracy associated with an expected progeny The agreement typically defines the difference. The measure ranges from breeding system, selection methods, Jeremy Powell 0 to 1, with values closer to 1 indicat­ management conditions and product Associate Professor ­ ing greater reliability because of the specifications for the cattle. inclusion of more information. Animal Science – A substance that reduces or Veterinarian – Adjustment factors Antisepticstops growth of organisms in or on Across­breed EPDsthat allow direct comparison of EPDs living tissue. from animals of different breeds. They – The are based upon across­breed EPD Artificial insemination (AI)technique of placing semen from the adjustment factors which are added to male into the reproductive tract of EPDs provided by the separate genetic the female by means other than evaluation of each breed. natural service. – The specific drug Active ingredient – Measurement component part of a chemical Averageof daily daily body gain weight (ADG) change in animals compound. on a feed or performance test. – A numerical Additivequantity added to an animal’s record adjustment factors to reflect expected performance if the B – The mating of a two­breed animal had belonged to some baseline Backcrosscrossbreed offspring back to one of group. For example, 60 pounds could its parental breeds. (Example: A be added to weaning weight records of Hereford­Angus crossbred back to an steer calves born from two­year­old Angus bull.) dams to represent expected weaning weight if their mother had been five –A to nine years of age. Beef Improvement Federation (BIF)federation of organizations, businesses and individuals interested or involved – An Adjusted weaning weight in performance evaluation of beef unshrinkable off­the­cow weight cattle. The purposes of BIF are to adjusted to 205 days of age and to a bring about uniformity of procedures, mature dam age equivalence. development of programs, cooperation – An among interested entities, education Adjusted yearling weightunshrinkable weight adjusted of members and the users’ perfor­ to either 365, 452 or 550 days of age. mance evaluation methods and to build confidence of the beef industry – Alternate forms of genes. in the principles and potentials of Arkansas Is Alleles Because genes occur in pairs in body performance testing. cells, one gene of a pair may have one Our Campus – A group of cattle breeds effect and another gene of that same Biological type pair (allele) may have a different having similar geographic origin and effect on the same trait. past selection history and with similar Visit our web site at: genetic potential for traits of economic https://www.uaex.uada.edu importance.

University of Arkansas, United States Department of Agriculture, and County Governments Cooperating – The weight of a calf taken within – The season(s) of the year when calves Birth weight (BW)24 hours of birth. Heavy birth weights tend to be cor­ Calving seasonare born. Limiting calving seasons is the first step to related with calving problems, but the conformation of performance testing the whole herd, accurate records the calf and the cow are contributing factors. and consolidated management practices. – A subjective assessment of the feed – Techniques of measuring Body capacityintake capacity of an individual or breed, typically Carcass evaluationcomponents of quality and quantity in carcasses. assessed by visually evaluating body length, body – Desirability of a carcass relative to depth and spring of ribs. Carcass meritquantity of components (muscle, fat and bone), USDA – A score reflecting the amount of quality grade, plus potential eating qualities. Body condition scorefat reserves in a cow’s body on a scale of 1 to 9, where – An estimate of palatability based 1 = very thin and 9 = extremely fat. Carcass quality gradeprimarily on marbling and matu rity and to a lesser – These are Zebu (humped) cattle including extent on color, texture and firmness of lean. Bos indicusthe Brahman breed in the United States. – A heterozygous individual having one recessive – Includes most cattle found in the United Carriergene and one dominant gene for a given pair of genes Bos taurusStates, including their European ancestors. (alleles). For example, an animal with one gene for polledness and one gene for horns will be polled but – Animals with a common origin and common can produce horned offspring when mated to another Breed characteristics that distinguish them from other animal carrying the gene for horns. groups of animals within that same species. – A location where animals from several herds – An organization that maintains Centralare assembled to evaluate differences in certain perfor ­ test Breed association pedigree and performance information and arranges mance traits under uniform management conditions. for timely genetic evaluation of animals within that breed. Breed associations also establish regulations for – A chromosome is a long DNA molecule on registration of animals, promote the breed and Chromosomewhich genes (the basic genetic codes) are located. advance the interests of the breeder members. Domestic cattle have 30 pairs of chromosomes. – The objective or “direction” of – Visible signs of poor health due to the Breeding program goalsbreeders’ selection programs. Goals are basic decisions Clinical diseasepresence of invading organisms. breeders must make to give “direction” to their breed­ – A herd into which no outside breeding ing programs. Goals should vary among breeders due Closed herdstock (cattle) is introduced. to relative genetic merit of their cattle, their resources and their markets. – Relatives of an individual that are Collateral relativesnot its ancestors or descendants. Brothers and sisters – Inspection of a bull are examples of collateral relatives. Breeding soundness examinationinvolving evaluation of physical conformation and soundness through genital palpation, scrotal circum­ – Producers whose primary goal ference and testing semen for motility and morphology. Commercial producersis to produce animals for herd replacement, feeding and slaughter rather than breeding stock for sale to – Value of an animal as a parent. The other producers. Breeding valueworking definition is twice the difference between a very large number of progeny and the population aver­ – Gain from cattle that have been age when individuals are mated at random with the Compensatory gainnutritionally deprived for part or all of their lives. population and all progeny are managed alike. The Once fed feedlot rations, they compensate for the difference is doubled because only one gene of each earlier restriction of feed by gaining very rapidly. pair is transmitted from a parent to each progeny. – The combining of breeds or individual – Breeds of cattle originating in Great Complementarityanimals that have characteristics that complement British breedsBritain, such as Angus, Hereford and Shorthorn. each other, thereby obtaining optimum progeny. – A breed made up of combinations of Composite breedother breeds. C – A process where the calf is removed Caesarean section – The shape and arrangement of the from the cow during parturition by making a large Conformation different body parts of an animal. incision in the right side of the cow just above the flank. – Acquired during prenatal life. Condition Congenitalexists at or dates from birth. Often used in the context – Abnormal or difficult labor, of congenital (birth) defects. Calving difficulty (dystocia) causing difficulty in delivering a fetus and/or placenta. – A group of cattle that are of the – An easy calving is one that does not Contemporary group Calving ease same breed and sex and have been raised in the same require assistance and does not impose undue strain management group (same location on the same feed on the calf or dam. and pasture). Contemporary groups should include as – A numerical score quantifying many cattle as can be accurately compared. Calving ease score calving ease, ranging from 1 for an easy, unassisted – Breeds originally developed calving through 5 for an abnormal presentation. Continentalon the continent (European) of Europe. breed – Number of calves born divided by the Calving ratenumber of cows exposed to a bull. – A measure of how two traits vary together. a function of number of progeny but is adjusted for CorrelationA correlation of +1.00 means that as one trait increases their distribution among herds and contemporary the other also increases – a perfect positive relation­ groups and for the number of contemporaries by other ship. A correlation of ­1.00 means that as one trait sires. EPN is less than the actual number because the increases the other decreases – a perfect negative, or distribution of progeny is never ideal. inverse, relationship. A correlation of 0.00 means that – Removing fertilized ova (embryos) as one trait increases, the other may increase or Embryo transfer decrease – no consistent relationship. Correlation from one cow (donor cow) and placing these embryos coefficients may vary between +1.00 to ­1.00. into other cows (recipient cows), usually accompanied by hormone­induced superovulation of the donor dam. – The mating of animals of different More calves can be obtained from cows of superior Crossbreedingbreeds (or species). Crossbreeding usually results in breeding value by this technique. Only proven heterosis (hybrid vigor). producers should become donor dams. – The process of eliminating less productive or – All external (non­genetic) conditions that Cullingless desirable cattle from a herd. Environmentinfluence the reproduction, production and carcass merit of cattle. – An estimate of the percentage of salable meat Cutability(muscle) from a carcass versus percentage of waste fat. – Concentration of drug or drug Percentage of retail yield of carcass weight can be esti­ Established safe levelmetabolite in tissue considered to be without hazard to mated by a USDA prediction equation that includes consumers and below which the FDA normally will not hot carcass weight, ribeye area, fat thickness and take regulatory action. estimated percentage of kidney, pelvic and heart fat. – An estimate of an Estimated breeding value (EBV) individual’s true breeding value for a trait based on performance of the individual and close relatives for D – The chemical compound the trait. EBV is a systematic way of combining avail­ Deoxyribonucleic acid (DNA)that stores within each cell genetic information unique able performance information on the individual, sibs to an individual. and progeny of the individual. Expected progeny differ­ ences have replaced EBVs in most breed associations. – A difference between an indi vidual record and Deviationthe average for that trait for that contemporary group. – Regularly recurrent state of sexual excitability Estrus These differences sum to zero when the correct aver­ during which the female (cow or heifer) will accept the age is used. A ratio deviation is the ratio less the male (bull). average ratio of 100. – Causing a group of cows or Estrus synchronization – A measure of an animal’s heifers to exhibit estrus together at one time by Disposition (temperament)docility, wildness or aggression toward unfamiliar situ­ artificial manipulation of the estrous cycle. ations, human handlers or management interventions. – The difference in Expected progeny difference (EPD) – Dominant genes affect the phenotype when performance to be expected from future progeny of an Dominancepresent in either homozygous or heterozygous condi­ individual compared with that expected from future tion. A dominant gene need only be obtained from one progeny of another individual. EPD is an estimate parent to achieve expression. based on progeny testing and is equal to one­half the estimate of breeding value obtainable from progeny – The amount of a drug or other substance given test records. Dosageto an animal at one time. – The use of an approved drug by a licensed – A simple recessive trait evidenced by Extra label Double muscling veterinarian in a manner that is not in accordance an enlargement of the muscles with large grooves with the approved label directions including use in between the muscle systems especially noticeable in another species, use for a different disease, or use at a the hind leg. different dose, frequency or route of administration. – Hot carcass weight divided by the This is a legitimate use of pharmaceuticals by condi­ Dressing percentagelive weight times 100. tions set in the Animal Medicinal Drug Use Clarifica­ tion Act of 1994, and a valid veterinarian/client/patient – A recessive trait in which the skeleton is quite relationship must be established. Dwarfismsmall and the forehead has a slight bulge. – Abnormal or difficult labor Dystocia (calving difficulty)causing difficulty in delivering the fetus and/or placenta. F – Offspring resulting from the mating of a purebred F1 (straight­bred) bull to purebred (straight­bred) females of another breed. E – The net returns within a herd for – Depth of fat in tenths of inches over the Economic value making a pound or percentage change of the trait Fat thicknessribeye muscles in the twelfth rib. It consists of a single in question. measurement at a point three­fourths of the lateral – Traits that are of direct length of the ribeye muscle from the split chine bone. Economically relevant trait economic importance to cattle producers. – Steers and heifers managed to produce Fed cattle – An indication of the high­quality carcasses (Prime, Choice and Select Effective progeny numberamount of information available for estimation of(EPN) quality grades). expected progeny differences in cattle evaluation. It is – Units of feed – Variation in the Feed conversion (feed efficiency) consumed per unit of weight gained; production (meat, Genotype ×relative performance of different genotypes from oneenvironment interaction milk) per unit of feed consumed. environment to another. For example, the “best” cattle (genotypes) for one environment may not be the “best” – The union of male and female gametes to for another environment. Fertilizationform a new individual. This union combines two hap­ loid cells to restore the diploid number of chromosomes – The period of pregnancy, or the period of time in the new individual. Gestationfrom conception until birth. – Pattern of DNA fragments unique to Fingerprint (DNA)an individual. Often produced by using restriction enzymes to cut the DNA into fragments at specific H – Individuals having the same sire or dam – sequences of nucleotides. These fragments can be sorted Half­sibshalf­brothers and/or half­sisters. and then visualized, forming a unique “fingerprint” for each different animal. – Through hormonal Heat (estrous) synchronizationmanipulation causing a group of cows or heifers to – A score based on subjective evaluation of initiate estrous cycles at approximately the same time. Frame scoreheight or actual measurement of hip height. This score is related to slaughter weight at which cattle should – Heifer pregnancy EPDs, grade Choice or have comparable amounts of fat. Heifer pregnancy EPDexpressed as probabilities of successful conception, predict differences among individuals in the ability of – Female born twin to a bull calf their daughters to conceive and calve at two years of age. Freemartin(approximately 9.8 out of 10 of the female twins will not be fertile). – The transmission of genetic or physical traits Heredityof parents to their offspring. – The proportion of the difference among Heritability G – A specific sequence of nucleotides that is cattle, measured or observed, that is transmitted to Gene markereasily detectable and can be used to differentiate the offspring. Heritability varies from zero to one. The among alleles at a locus. higher the heritability of a trait, the more accurately does the individual performance predict breeding – A breed with acceptable genetic value and the more rapid should be the response due General purpose breed merit in reproductive, maternal, growth and carcass to selection for that trait. traits but not specialized in either terminal or maternal characteristics. – An estimate of the proportion of Heritability estimatethe total phenotypic variation between individuals for – Average age of the parents when a certain trait that is due to heredity. More specifically, Generation interval offspring destined to replace them are born. A genera­ hereditary variation due to additive gene action. tion represents the average rate of turnover of a herd. – Amount by which measured – The basic unit of heredity that occurs in pairs Heterosis (hybrid vigor)traits of the crossbreds exceed the average of the two Genes and has its effect in pairs in the individual but is or more purebreds mated to produce the crossbreds. transmitted singly (one or the other gene at random of each pair) from each parent to offspring. – Genes of a specific pair (alleles) are Heterozygousdifferent in an individual. – A genetic correlation in which Genetic antagonismdesirable genetic change in one of the traits is – Genes of a specific pair (alleles) are alike Homozygous accompanied by an undesirable change in the other. in an individual. – Correlations between two traits – Weight of carcass just prior to chilling. Hot carcass weight Genetic correlationsthat arise because some of the same genes affect both traits. When two traits (i.e., weaning and yearling weight) are posi tively and highly correlated to one I – Production of offspring from parents more another, successful selection for one trait will result in Inbreeding an increase in the other trait. When two traits are closely related than the average of a population. negatively and highly correlated (i.e., birth weight and Inbreeding increases the proportion of homozygous calving ease) to one another, successful selection for gene pairs and decreases the proportion of heterozy­ one trait will result in a decrease in the other trait. gous gene pairs. Also, inbreeding increases prepotency and facilitates expression of undesirable recessive genes. – A diagram showing where genes Genetic linkage mapand markers are located on a chromosome and their – A numerical measure, ranging Inbreeding coefficient relationship to one another. from 0 to 1.0, of the intensity of inbreeding of an indi­ vidual. It represents the proportion of gene loci in the – An estimate of the annual change in individual at which both genes are identical copies of Genetic trend genetic merit of individuals within a breed for a trait. the same ancestral gene. – The entire complement of DNA characteristic – The reduction in performance Genome to individuals of a species. Inbreeding depressionlevel for many economically important traits that – Actual genetic makeup (constitution) of an accompanies, on average, an increase in inbreeding Genotypeindividual determined by its genes or germ plasm. coefficient. For example, there are two genotypes for the polled phenotype PP (homozygous dominant) and Pp (heterozygote). – A situation in which neither – An EPD representing the effect of the Incomplete dominancegene within a gene pair dominates the other, with the Maternal EPDgenes of an individual’s daughters on the trait of inter­ result that both are expressed in the phenotype which est. A calving ease maternal EPD, for example, repre­ is intermediate between the two traits. sents the ease with which an individual’s daughters calves are born. – Selection of culling based on Independent culling levelscattle meeting specific levels of performance for each – Amount by which the average trait included in the breeder’s selection program. For Maternal heterosis performance for a trait in the progeny of crossbred example, a breeder could cull all heifers with weaning cows exceeds the average performance of progeny of weights below 400 pounds (or those in the bottom purebred cows of the two or more breed ancestors of 20 percent on weaning weight) and yearling weights the crossbred cows. below 650 pounds (or those in the bottom 40 percent). – Sires whose major function is to sire – Placement of drugs and other substances Maternal siresdaughters with outstanding genetic merit for repro­ Intramammarydirectly into the udder usually through the teat opening. ductive and maternal traits, adaptability to prevailing environmental conditions and longevity. – An injection into the muscle. Intramuscular injection (IM) – An estimation of the chronological age of an – Injection into the body space Maturity Intraperitoneal injection animal or carcass by assessing the physiological stages surrounding the gastrointestinal tract. of maturity of bone and muscle characteristics. – Injection in the rumen. Intraruminal injection – The weight of an animal raised to Metabolic body size 75 – Placement of drugs and other substances the three­fourths power (W. ); a figure indicative of Intrauterinedirectly into the uterus. metabolic needs and of the feed required to maintain a certain body weight. – Injection of a drug or other Intravenous injection (IV)substance directly into a vein. – The transformation by which energy is Metabolismmade available for body use. – A living creature, such as a virus or Microorganisms K – Internal carcass fat bacterium, capable of being seen only under a microscope. Kidney, pelvic and heart fat (KPH) associated with the kidney, pelvic cavity and heart – Form and structure of individual sperm expressed as a percentage of chilled carcass weight. Morphologycells. The kidney is included in the estimate of kidney fat. – An estimate of Most probable producing ability (MPPA)a cow’s future productivity for a trait (such as progeny weaning weight ratio) based on her past productivity. L – Written information detailing the content, For example, a cow’s MPPA for weaning ratio is calcu­ Labelingintended use, instructions for use, withholding times lated from the cow’s average progeny weaning ratio, and other specifics attached to the drug container the number of her progeny with weaning records and and/or on a separate sheet accompanying the container. the repeatability of weaning weight. – The period following calving during which – The vigor and number of cells moving in a Lactationmilk is formed in the udder. Motility linear progressive manner. – A gene or genes that may cause the death – A genetic prediction Lethal geneof an individual who expresses them. Multiple breed evaluation simultaneously utilizing data from more than one breed or crossbred group. It accounts not only for – Sexual desire or sex drive. Libido differences among animals in transmissible genetic – A form of inbreeding in which an attempt value (EPDs) but also in breed differences and Linebreedingis made to concentrate the inheritance of one ancestor, heterosis effects. or line of ancestors, in a herd. The average relation­ – A genetic prediction which uses ship of the individuals in the herd to this ancestor Multiple trait evaluationphenotypic measurements of two or more genetically (outstanding individual or individuals) is increased correlated traits (birth weight, weaning weight and by linebreeding. post­weaning gain, for example) to simultaneously – Offspring produced by crossing two or more estimate breeding values for each of the traits. Com­ Linecrossinbred lines. pared to single trait evaluations, multiple trait evalua­ tions produce EPDs with slightly higher accuracy and less bias from selection. M – The amount of feed Maintenance energy requirementenergy required per day by an animal to maintain its body weight and support necessary metabolic functions. N – Programs of cattle evaluation National cattle evaluation conducted by breed associations to genetically compare – The specks of fat (intramuscular fat) distributed animals. Carefully conducted national cattle evaluation Marblingin muscular tissue. Marbling is usually evaluated in programs give unbiased estimates of expected progeny the ribeye between the twelfth and thirteenth rib. differences (EPDs). Cattle evaluations are based on – For weaning weight, the dam’s maternal field data and rely on information from the individual Maternal effectability which influences preweaning growth. animal, relatives and progeny to calculate EPDs. – Favorable effects or actions – A pedigree that includes Nonadditive gene effectsproduced by specific gene pairs or combinations. Non­ Performance pedigreeperformance records of the individual, ancestors, additive gene action is the primary cause of heterosis. relatives and progeny in addition to the usual pedigree Nonadditive gene action occurs when the heterozygous information. Some breed associations include expected genotype is not intermediate in phenotypic value to progeny differences. the two homozygous genotypes. – The systematic collection of – Cull cows and bulls sold for slaughter. Performance testingcomparative production information for use in decision Non­fed cattle Carcasses usually fall into Commercial, Utility, Cutter making to improve efficiency and profita bility of beef and Canner quality grades. production. Differences in performance among cattle – The number of animals of must be utilized in decision making for performance Number of contemporariessimilar breed, sex and age against which an animal testing to be beneficial. The most useful performance is compared in performance tests. The greater the records for management, selection and promotion number of contemporaries, the greater the accuracy decisions will vary among purebred breeders and of comparisons. for purebred breeders compared with commercial cattle producers. – The visible or measurable expression of a Phenotypecharacter; for example, weaning weight, post­weaning O – The use of veterinary pharmaceuticals by a gain, reproduction, etc. Genotype and environment Off labelproducer for unapproved dosage, frequency or route of influence phenotype. administration or in an unapproved age group. This use is illegal and punishable by the FDA. – Correlations between two Phenotypic correlationstraits caused by both genetic and environmental – The most profitable or factors influencing both traits. Optimum level of performancefavorable ranges in levels of performance for the eco­ nomically important traits in a given environment and – Naturally hornless cattle. Having no horns or management system. For example, although many Polledscurs. cows produce too little milk, in every management sys­ – The enzyme system that facilitates the tem there is a point beyond which higher levels of milk Polymerasereplication of DNA or RNA. production may reduce fertility and decrease profit. – A process used to – Placement of a drug or other substance into an Polymerase chain reaction (PCR)rapidly amplify DNA. Oralanimal through its mouth. – The existence of two or more alleles at a – Drugs and other substances that can be bought by Polymorphismgene locus in a population. OTCanyone over the counter because adequate instructions for layman use can be printed on the label. – The amount by which an individual’s Possible changecurrent EPD might reasonably be expected to change – Mating together of animals Outbreeding (outcrossing) (either upwards or downwards) as more information that are not closely related. becomes available in subsequent national cattle – Mating of individuals that are less closely evaluations. Outcrossing related than the average of the breed. Commercial – After the birth of an individual. breeders and some purebred breeders should be out­ Postpartum – The number of days between crossing by periodically adding new sires that are Postpartum interval unrelated to their cow herd. This outcrossing should parturition and the first postpartum estrus. reduce the possibility of loss of vigor due to inbreeding. – A measure of Pounds of retail cuts per day of age – Release of the female germ cell (egg) by the cutability and growth combined calculated as follows: Ovulationovary. Cows usually ovulate several hours (up to cutability times carcass weight divided by age in days. 15 hours) after the end of estrus or standing heat. It is reported as lean weight per day of age (LWDA) by some associations. – Parts per billion. ppb P – Acceptable to the taste or sufficiently – Parts per million. Palatability ppm agreeable in flavor to be eaten. – The ability of a parent to transmit Prepotent – The act of giving birth; calving. characteristics to its offsprings so they resemble that Parturition parent or each other more than usual. Homozygous – A tabulation of names of ancestors, usually Pedigree dominant individ uals are prepotent. Also, inbred cattle only those of the three to five closest generations. tend to be more prepotent than outbred cattle. – The percentage of calves produced Percent calf crop – Weight gained between birth and within a herd in a given year relative to the number of Preweaning gainweaning. cows and heifers exposed to breeding. – The young, or offspring, of the parents. – Records of an individual animal for Progeny Performance datareproduction, production and possibly carcass merit. – The average comparative performance Progeny records Traits include birth, weaning and yearling weights, of the progeny of sires and dams. calving ease, calving interval, milk production, etc. – Evaluating the genotype of an individual Progenyby a study of its progeny records. testing – The age at which reproductive organs become – The difference between Pubertyfunctionally operating and secondary sex Residual feed intake (RFI) actual and expected feed intake. characteristics begin to develop. – Remnants of the compounds in drugs and – An animal of known ancestry within a Residuesother substances found in fluid, tissues and feeds. Purebredrecognized breed that is eligible for registry in the – Area of the longissimus muscle measured official herd book of that breed. Ribeye areain square inches at the twelfth rib interface on the beef forequarter. – A system of crossing two or Q – Traits in which there is a sharp Rotational crossbreedingmore breeds where the crossbred females are bred to Qualitative traits distinction between phenotypes, such as black or bulls of the breed contributing the least genes to that white or polled or horned. Usually, only one or a few female’s genotype. Rotation systems maintain rela­ pairs of genes are involved in the expression of tively high levels of heterosis and produce replacement qualitative traits. heifers from within the system. Opportunity to select replacement heifers is greater for rotation systems – Traits in which there is no sharp than for other crossbreeding systems. Quantitative traitsdistinction between phenotypes, with a gradual varia­ tion from one phenotype to another, such as weaning – The method by which a drug weight. Usually, many gene pairs are involved, as well Route of administrationor other substance is given to an animal; i.e., oral, as environmental influences. subcutaneous, intramuscular, topical, etc. – Drugs that must be prescribed Rx (prescription drugs)by a licensed veterinarian. R – A system of mating where every Random matingfemale (cow and/or heifer) has an equal chance of being assigned to any bull used for breeding in a par­ S – Clean; absence of organisms that can cause ticular breeding season. Random mating is required Sanitarydisease or ill health. for accurate progeny tests. – A measure of testis size obtained – Rate of improvement per Scrotal circumferenceby measuring the distance around the testicles in Rate of genetic improvementunit of time (year). The rate of improvement is depen­ the scrotum with a circular tape. Related to semen­ dent on (1) heritability of traits considered, (2) selec­ producing capability and age at puberty of female sibs tion differentials, (3) genetic correlations among traits and progeny. considered, (4) generation interval in the herd and (5) the number of traits for which selections are made. – Horny tissue or rudimentary horns attached to Scurs – An expression of an animal’s performance for a the skin rather than the bony parts of the head. Ratio particular trait relative to the herd or contemporary – Producers of breeding stock for group average. It is usually calculated for most Seedstock breederspurebred and commercial breeders. Progressive seed­ traits as: stock breeders have comprehensive programs designed Individual Record to produce an optimum or desirable combination of Average of Animals in Group 5 100 economical traits (genetic package) that will ultimately increase the profitability of commercial beef production. – Recessive genes affect the phenotype – Causing or allowing certain individuals in a Recessive gene only when present in a homozygous condition. Reces­ Selectionpopulation to produce offspring in the next generation. sive genes must be received from both parents before the phenotype caused by the recessive genes can – The difference between Selection differential (reach) be observed. the average for a trait in selected cattle and the aver­ age of the group from which they came. The expected – A bull designated to be used as a response from selection for a trait is equal to selection Reference sire benchmark in progeny testing other bulls (young differential times the heritability of that trait. sires). Progeny by reference sires in several herds enable comparisons to be made between bulls not – A formula that combines performance Selection index producing progeny in the same herd(s). records from several traits or different measurements of the same trait into a single value of each animal. – A measure of the relationship Regression (regressed) Selection indexes weigh the traits for their relative net between two variables. The value of one trait can be eco nomic importance and their heritabilities plus the predicted by knowing the value of the other variable. genetic associations among the traits. For example, easily obtained carcass traits (hot car­ cass weight, fat thickness, ribeye area and percent of – A measure of the motivation, willingness Serving capacity internal fat) are used to predict percent cutability. and ability of a bull to detect and service females Likewise, breeding value estimates based on limited in estrus. data are regressed back toward the population average – Brother and sisters of an individual. to account for the imperfection of this relationship. Sibs – When the difference in – The amount by which net Sire x environment interactionprogeny performance among sires is dependent upon Relative economic valueincome to the cattle enterprise will change, per unit some factor of the environment under which the change in genetic merit for a trait. progeny were compared. – Published results of sires from national Sire summarycattle evaluation programs. V – A preparation containing microorganisms – A mature male germ cell. Vaccinecontrolled in such a way as to create a response by Sperm the recipient animal’s body that results in increased – An injection under the skin. Subcutaneous (SubQ) protective immunity. – Process by which a cow produces more Superovulation – Valid veterinarian/client/patient relationship, eggs than normal. Done in embryo transfer techniques. VCPRgenerally meaning that the veterinarian knows and – An approach to evaluating regularly sees the animals and the individual responsi­ Systems approachalternative individuals, breeding programs and selec­ ble for authorizing medical treatment for those animals tion schemes that involves assessment of these alter­ agrees to follow the veterinarian’s instructions. natives in terms of their net impact on all inputs and – Variance is a statistic that describes the outputs in the production system. This approach Variancevariation we see in a trait. Without variation, no specifically recognizes that intermediate optimum genetic progress is possible, since genetically superior levels of performance in several traits may be more animals would not be distinguishable from genetically economically advantageous than maximum inferior ones. performance for any single trait.

W – Number of calves weaned divided by T – Selection for one trait at a time. Weaning ratenumber of cows exposed to a bull. Tandem selectionWhen the desired level is reached in one trait, then selection is practiced for a second trait. – Weight of an individual Weight per day of age (WDA)divided by days of age. – Sires used in a crossbreeding system Terminal sireswhere all their progeny, both male and female, are – The amount of time, usually Withholding times marketed. For example, F1 crossbred dams could be expressed in hours, days or number of milkings that bred to sires of a third breed and all calves marketed. must occur, before the milk or meat from an animal Although this system allows maximum heterosis and treated with a drug may be sold. complementary breeds, replacement females must come from other herds. – Treatment of disease or health disorders. Y – Measurements of carcass cutability Therapy Yield gradecategorized into numerical categories with 1 being the – Maximum legally allowable level or leanest and 5 being the fattest. Yield grade and Toleranceconcentration of a drug or chemical in a food product cutability are based on the same four carcass traits. at the time the milk is marketed or the animal is slaughtered. – Application of a drug or other substance to the Topical skin surface or an external membrane, usually References concentrated in a small area. Executive Summary of the National Non­Fed Beef Quality Audit. 1994. National Cattlemen’s Beef Association. Englewood, Co. U – Used to estimate carcass and Guidelines for Uniform Beef Improvement Program. Ninth Ultrasonic measurementreproductive characteristics. Operates off the principle Edition. Beef Improvement Federation. that sound waves echo differently with different densities of tissues. – Measurements of carcass cutability USDA yield gradecategorized into numerical categories, with 1 being the leanest and 5 being the fattest. Yield grade and cuta­ bility are predicted from the same four carcass traits.

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TOM R. TROXEL, Ph.D., is professor and associate department Issued in furtherance of Cooperative Extension work, Acts of May 8 and head ­ animal science, Little Rock. JEREMY POWELL, DVM, Ph.D., June 30, 1914, in cooperation with the U.S. Department of Agriculture, is associate professor ­ animal science veterinarian, Fayetteville. They Director, Cooperative Extension Service, University of Arkansas. The are employees of the University of Arkansas Division of Agriculture, Arkansas Cooperative Extension Service offers its programs to all eligi­ Department of Animal Science. ble persons regardless of race, color, national origin, religion, gender, age, disability, marital or veteran status, or any other legally protected FSA3112­PD­2­12RV status, and is an Affirmative Action/Equal Opportunity Employer.