Beef Production Glossary

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Accuracy (of selection) - Correlation between an animal's unknown actual breeding value and a calculated estimated breeding value.

Adjusted weaning weight (WW) - An unshrunk, off-the-cow weight adjusted to 205 days of age and to a mature-dam age equivalence.

Adjusted yearling weight (YW) - An unshrunk weight adjusted to either 365, 452, or 550 days of age.

Alleles - Alternate forms of genes. Because most genes occur in pairs in body cells, one gene of a pair may have one effect and another gene of the same pair (allele) may have a different effect on the same trait.

Artificial insemination (A.I.) - The technique of placing semen from the male into the reproductive tract of the female by means other than natural service.

Average daily gain (ADG) - Measurement of daily body weight change in animal on a feed test. Most bull tests are 140 days in length.

Backcross - The mating of a crossbred offspring back to one of its parental breeds. Example A Herford x Angus cross cow bred back to an Angus bull.

Beef Carcass Evaluation Service - A USDA program whereby producers, for a fee, can receive carcass evaluation data on their cattle by using eartags, ear tattoos, or backtags to identify slaughter animals. Contact the nearest USDA Meat Grading and Certification Office for information.

Beef Cattle Improvement Association (BCIA) - An organization, usually at the state level, that sponsors beef cattle improvement programs.

Beef Improvement Federation (BIF) - A federation of organizations, businesses, and individuals interested or involved in performance evaluation of beef cattle. The purposes of BIF are to bring about uniformity of procedures, development of programs, cooperation among interested entities, education of all segments of the beef industry concerning performance evaluation methods, and to build confidence in the principles and potentials of performance testing.

Birth weight (BW) - The weight of a calf taken within 24 hours after birth. Heavy birth weights tend to be correlated with calving problems, but the conformation of the calf and the cow are contributing factors.

Body condition score - A score on a scale of 1 to 9, reflecting the amount of fat reserves in a cow's body, where 1 = Severely Emaciated and 9 = Very Obese.

Bos indicus - These are the Zebu (humped) cattle, including the Brahman breed in the United States.

Bos taurus - Includes most cattle found in the United States and their European ancestors.

Breed - Animals which have a common origin and common characteristics which distinguish them from other groups of animals within that same subspecies.

Breeding program goals - The objective or "direction" of breeders' selection programs. Goals are basic decisions breeders must make to give "direction" to their breeding program. Goals will vary among breeders because relative genetic merit of their cattle, their resources, and their markets differ.

Breeding soundness examination - Inspection of a bull involving evaluation of physical conformation and soundness through genital palpation, scrotal circumference measurement, and testing semen for motility and morphology.

Breeding value - Value of an animal as a parent. The working definition is twice the difference in performance between a very large number of progeny and the population average when individuals are mated at random within the population and all progeny are managed alike. The difference is doubled because only a sample half (one gene of each pair) is transmitted from a parent to each progeny. Breeding value exists for each trait and is dependent on the population in which the animal is evaluated. For a given trait, an individual can be an above-average producer in one herd and a below-average producer in another herd.

Caesarean section - A process where the calf is removed from the cow during parturition by making a large incision in the right side of the cow just above the flank.

Calf crop - See Percent calf crop.

Calving difficulty (dystocia) - Abnormal difficult labor, causing difficulty in delivering the fetus and (or) placenta.

Calving season - The season(s) of the year when the calves are born. Limiting calving season is the first step to performance testing the whole herd, accurate records, and consolidated management practices.

Carcass evaluation - Techniques of measuring components of quality and quantity in carcasses.

Carcass merit - Desirability of a carcass relative to quantity of components (muscle, fat, and bone), USDA quality grade, plus potential eating qualities.

Carcass quality grade - An estimate of palatability based primarily on marbling and maturity and generally to a lesser extent on color, texture, and firmness of lean.

Carrier - A heterozygous individual having one recessive gene and one dominant gene for a given pair of genes (alleles). For example, an animal with one gene for polledness and one gene for horns will be polled but can produce horned offspring when mated to another animal carrying the gene for horns.

Central test - A location where animals are assembled from several herds to evaluate differences in certain performance traits under uniform management conditions.

Chromosomes - Chromosomes within the nucleus contain long DNA molecules on which genes (the basic genetic codes) are located. Domestic cattle have 30 pairs of chromosomes in their body cells.

Closed herd - A herd in which no outside breeding stock (cattle) are introduced.

Collateral relatives - Relatives of an individual that are not its ancestors or descendants. Brothers and sisters are examples of collateral relatives.

Compensatory gain - Gain from cattle that have been nutritionally deprived for part of all of their life. Once fed feedlot rations they compensate for the earlier restriction of feed by gaining very rapidly.

Conception - The fertilization of the ovum (egg). The act of conceiving or becoming pregnant.

Conformation - The shape and arrangement of the different body parts of an animal.

Congenital - Acquired during prenatal life. Condition exists at or dates from birth. Often used in the context of congenital (birth) defects.

Contemporary group - a group of cattle of similar age that are of the same breed and sex and have been raised in the same management group (same location, on the same feed and pasture, etc.)

Correlation - A measure of how two traits vary together. A correlation of +1.00 means that as one trait increases the other also increases - a perfect positive relationship. A correlation of -1.00 means that as one trait increases the other decreases - a perfect negative, or inverse, relationship. A correlation of 0.00 means that no relationship exists between traits. Correlation coefficients may vary between +1.00 and -1.00.

Crossbreeding - The mating of animals of different breeds (or species). Crossbreeding often results in heterosis (hybrid vigor).

Culling - The process of eliminating less productive or less desirable cattle from a herd.

Cutability - An estimate of the percentage of salable meat (muscle) from a carcass. Percentage of retail yield of carcass weight can be estimated by a USDA prediction equation that includes hot carcass weight, rib-eye area, fat thickness, and estimated percent of kidney, pelvic, and heart fat.

Dam - The female parent.

Deviation - A difference between an individual record and the average for that trait for that contemporary group. These differences sum to zero when the correct average is used. A ratio deviation is the ratio less the average ratio (usually 100).

DNA (deoxyribonucleic acid) - The basic hereditary material of organisms. A primary component of chromosomes. DNA is a strand of linked nucleotides, with each nucleotide consisting of a sugar moiety, phosphate group and organic base. An individual's genetic makeup is determined by its DNA sequence or code.

DNA fingerprinting - A method of visualizing similarities and differences between individuals based on genetic makeup. The DNA fingerprint is usually displayed as a series of bands. Differences in banding patterns indicate differences in the DNA sequences between individuals. This procedure can be used to verify animal identification or parentage.

Dominance - One allele masks the effect of another (recessive) allele. Dominant genes affect the phenotype when present in either homozygous or heterozygous condition.

Double muscling - A simple recessive trait evidenced by an enlargement of the muscles with large grooves between the muscle systems, especially noticeable in the hind leg.

Dressing percent - (Chilled carcass weight / live weight) X 100.

Dwarfism - A recessive trait in which the skeleton is quite small and the forehead has a slight bulge.

Dystocia (calving difficulty) - Abnormal or difficult labor causing difficulty in delivering the fetus and (or) placenta.

Economic trait locus (ETL) - Area of a chromosome at which exists a gene that has a direct effect on a trait of economic interest. Similar to quantitative trait locus (QTL), except that ETL can refer either to qualitative or quantitative traits.

Economic value - The net return within a herd for making a pound of percentage change of the trait in question.

Effective progeny number (EPN) - An indication of the amount of information available for estimation of expected progeny differences in cattle evaluation. It is a function of number of progeny, but is adjusted for their distribution among herds and contemporary groups and for the number of contemporaries by other sires. EPN is less than the actual number because the distribution of progeny is never ideal.

Embryo - A fertilized ovum (egg) in the earlier stages of prenatal development, usually prior to development of body parts.

Embryo transfer - Removing fertilized ova (embryos) from one cow (donor dam) and placing these embryos into other cows (recipient cows), usually accompanied by hormone-induced superovulation of the donor dam. More calves can be obtained from cows of superior breeding value by this technique. Only proven producers should become donor dams.

Environment - All external (non-genetic) conditions that influence the expression of cattle traits (reproduction, production, and carcass merit).

Estimated breeding value (EBV) - An estimate of an individual's true breeding value for a trait based on the performance of the individual and (or) close relatives for the trait. EBVs for growth traits are generally expressed as ratios. Expected progeny differences have replaced EBVs in most breed association programs.

Expected progeny different (EPD) - The difference in performance to be expected from future progeny of an individual, compared with the average. EPD is an estimate based on available data and is equal to one-half the estimate of breeding value. EPDs are generally reported in the units of measure of the trait (e.g., lb.,cm., etc.)

F₁ - Offspring resulting from the mating of a purebred (straightbred) bull to purebred (straightbred) females of another breed.

Fat thickness - Depth of fat in tenths of an inch over the rib-eye muscle at the 12 rib. It consists of a single measurement at a point three-fourths of the lateral length of the rib-eye muscle from the split chine bone.

Feed conversion (feed efficiency) - Units of feed consumed per unit of weight gained. Also the production (e.g., meat, milk) per unit of feed consumed.

Fertilization - The union of the male and female gametes to form a new individual. This union combines two haploid cells to restore the diploid number of chromosomes in the new individual.

Fetus - The developing individual in intrauterine life after the body parts are formed, and before birth.

Frame score - A score based on subjective evaluation of height of actual measurement of hip height.  This score is related to slaughter weights at which cattle should attain a given quality grade or attain a given amount of fat thickness.

Freemartin - Female born twin to a bull calf (approximately 9 out of 10 will be infertile).

Gene - The basic unit of heredity. Most occur in pairs in the individual, but are transmitted singly (one or the other gene at random of each pair) from parent to offspring.

Gene map - A blueprint of the chromosomes of a species, indicating the relative order of location of genes and DNA markers.

Generation interval - Average age of the parents when the offspring destined to replace them are born. A generation represents the average time interval for turnover of a herd.

Genetic correlations - Correlations between two traits that arise because some of the same genes affect both traits. When two traits (e.g., weaning and yearling weight) are positively and highly correlated to one another, successful selection for change in one trait will result in change in the same direction in the other trait. When two traits are negatively and highly correlated (e.g., birth weight and calving ease) to one another, successful selection for change in one trait will result in a change in the opposite direction in the other trait.

Genotype - Actual genetic makeup (construction) of an individual determined by its genes or germ plasm. For example, there are two genotypes of the polled phenotype [PP (homozygous dominant) and Pp (heterozygote)].

Genotype X Environment Interaction - Variation in the relative performance of different genotypes from one environment to another. For example, the "best" cattle (genotypes) for one environment may not be the "best" for another environment.

Gestation - The period of pregnancy, or the period of time from conception until young are born.

Grading-up - Purebred sires of a single breed are used in a herd, generation after generation. Female replacements are selected within the herd.

Half-sibs - Individuals having the same sire or dam. Half-brothers and (or) half-sisters.

Heat synchronization - Causing a group of cows or heifers to exhibit heat together at one time by artificially manipulating estrous cycles.

Heredity - The transmission of genetic or physical traits of parents to their offspring.

Heritability - The portion of the differences among cattle, measured or observed, that is transmitted to the offspring.

Heritability estimate - An estimate of the proportion of the total phenotypic variation between individuals for a certain trait that is due to heredity. More specifically, the percentage of total variation due to additive genetic effects.

Heterosis (hybrid vigor) - Amount by which measured traits of the crossbreds exceed the average of the two or more purebreds that are mated to produce the crossbreds.

Heterozygous - Genes of a specific pair (alleles) are different in an individual (e.g., Aa).

Homozygous - Genes of a specific pair (alleles) are alike in an individual (e.g., AA or aa).

Hot carcass weight - Weight of carcass just prior to chilling.

Inbreeding - Production of offspring from parents more closely related than the average of a population. Inbreeding increases the proportion of homozygous gene pairs and decreases the proportion of heterozygous gene pairs. Also, inbreeding increases prepotency and facilitates expression of undesirable recessive genes.

Incomplete dominance - A situation in which neither gene of a gene pair is completely dominant to the other with the result that both are expressed in the phenotype. Phenotypic expression for the heterozygous genotype will be intermediate to that of the two homozygotes.

Independent culling levels - Selection of culling based on cattle meeting specific levels of performance for each trait included in the breeder's selection program. For example, a breeder could cull all heifers with weaning weights below 400 lb. (or those in the bottom 20 percent on weaning weight) and yearling weights below 650 lb. (or those in the bottom 40 percent).

Integrated Resource Management (IRM) - National program that utilizes team problem solving and innovative measurement tools for the development of whole farm/ranch plans.

Involution - The return of an organ to its normal size or condition after enlargement, as of the uterus after parturition. A decline in size or activity of other tissues; the mammary glad tissues normally involute with advancing lactation.

Kidney, pelvic and heart fat (KPH) - the internal carcass fat associated with the kidney, pelvic cavity and heart expressed as a percentage of chilled carcass weight. The kidney is included in the estimate of kidney fat.

Lactation - The period following calving during which milk is formed in the udder.

Lethal Gene - A gene, or genes, that cause the death of an individual at some stage of life.

Libido - Sexual desire or sex drive.

Linebreeding - A form of inbreeding in which an attempt is made to concentrate the inheritance of one ancestor, or line of ancestors, in a herd. The average relationship of the individuals in the herd to this ancestor (outstanding individual or individuals) is increased by linebreeding.

Linecross - Offspring produced by crossing two or more inbred lines.

Locus - The specific area on a chromosome where a particular gene is located.

Longissimus dorsi - Muscle that is measured to determine rib-eye area in a beef carcass.

Marbling - The specks of fat (intramuscular fat) distributed in muscular tissue. Marbling is usually evaluated in the rib-eye between the 12th and 13th rib.

Marker-assisted selection - A method of genetic evaluation which takes into consideration the DNA marker genotype along with conventional selection procedures.

Maturity - An estimation of the chronological age of the animal or carcass. This is accomplished by assessing the physiological stages of maturity of bone and muscle characteristics.

Metabolic body size - The weight of the animal raised to the 3/4 power (W^0.75); a figure indicative of metabolic needs and of the feed required to maintain a certain body weight.

Metabolism - The transformation by which energy is made available for body uses.

Molecular (DNA) markers - Areas of the genome at which differences in the DNA sequence can be visually detected. A marker locus by itself may not have a direct effect on a phenotypic trait, but it may be located close to a gene that does directly affect a trait (ETL). Markers can serve as location reference points for gene mapping and marker-assisted selection.

Molecular (DNA) probe - A method to determine an animal's genotype for a particular gene or marker.

Most probable producing ability (MPPA) - An estimate of a cow's future productivity for a trait (such as progeny weaning weight ratio) based on her past productivity. For example, a cow's MPPA for weaning ratio is calculated from the cow's average progeny weaning ratio, number of her progeny with weaning records, and repeatability of weaning weight.

National Cattle Evaluation (NCE) - Programs of cattle evaluation conducted by breed associations to compare genetically animals across herds or generations. Carefully conducted national cattle evaluation programs give unbiased estimates of expected progeny differences (EPSs). Cattle evaluations are based on field data and rely on information from the individual animal, relatives and progeny to calculate EPDs.

National Cattlemen's Beef Association (NCBA) - A national spokesman for the beef cattle industry. Principal services are governmental affairs, public information, management, education, and economic information for members.

Nonadditive gene effects - Effects of actions produced by specific gene pairs or combinations. Nonadditive gene action is the primary cause of heterosis. One type of nonadditive genetic effect occurs when the heterozygous genotype is not intermediate in phenotypic value to the two homozygous genotypes.

Number of contemporaries - The number of animals of similar breed, sex, and age, against which an animal was compared in performance tests. The greater the number of contemporaries, the greater the accuracy of comparisons.

Optimum level of performance - The most profitable or favorable ranges in levels of performance for the economically important traits in a given environment and management system.  For example, although many cows produce too little milk, in every management system there is a point beyond which higher levels of milk production may reduce fertility and decrease profit.

Outbreeding - Mating of animals less closely related than the average of the population

Outcrossing - Mating of individuals that are less closely related than the average of the breed.  Commercial breeders and some purebred breeders should be outcrossing by periodically adding new sires that are unrelated to their cow herd. This outcrossing reduces the possibility of loss of vigor caused by increasing.

Ovulation - Release of the female germ cell (egg) by the ovary. Cows usually ovulate several hours (up to 15 hours) after the end of estrus or standing heat.

Ovum - The female reproductive cell (gamete).

Palatability - Degree to which food (e.g., beef) is acceptable to the taste or sufficiently agreeable in flavor to be eaten.

Parturition - The act of giving birth (calving).

Pedigree - A tabulation of ancestors, usually those of the three to five most recent generations.

Percent calf crop - The percentage of calves produced within a herd in a given year relative to the number of cows and heifers exposed to breeding.

Performance data - The record of the individual animal for reproduction, production, and carcass traits. These traits include birth, weaning and yearling weights, calving ease, calving interval, milk production, etc.

Performance pedigree - A document that includes performance information for the individual, its ancestors, progeny, and collateral relatives, in addition to the usual pedigree information.

Performance testing - The systematic collection of comparative production information for use in decision making to improve efficiency and profitability of beef production.

Phenotype - The visible or measurable expression of a character; for example, weaning weight, postweaning gain, coat color, reproduction, etc. Phenotype is influenced by genotype and environment.

Phenotype correlations - Correlations between two traits caused by both genetic and environmental factors influencing both traits.

Polled - Naturally hornless cattle. Having no horns or scurs.

Polymorphism (many forms) - Refers to the situation in which there is more than one possible phenotype associated with a single locus, e.g., horned vs polled cattle. The most useful DNA markers are very highly polymorphic.

Pounds of retail cuts per day of age - A measure of cutability and growth combined; it is calculated as follows: cutability times carcass weight divided by age in days. A similar value is reported as lean weight per day of age (LWDA) by some associations.

Possible change - An alternative way to express accuracy of an EPD. About two-thirds of the animals in a given National Cattle Evaluation should have true progeny differences within the range of EPD plus or minus their possible change value.

Postpartum - After birth of an individual.

Postweaning Gain - Weight gained after a calf is weaned. Often expressed as ADG.

Propotent - The ability of a parent to transmit its characteristics to its offspring so that they resemble that parent more then usual. Homozygous dominant individuals are prepotent. Also, inbred cattle tend to be more prepotent than outcrossed cattle.

Preweaning gain - Weight gained between birth and weaning.

Progeny - Offspring of the parents.

Progeny records - Average comparative performance of the progeny of sires and dams.

Progeny testing - Evaluating the genotype of an individual by a study of its progeny.

Puberty - The age at which the reproductive organs become functionally operative and secondary sex characteristics begin to develop.

Purebred - An animal of known ancestry within a recognized breed that is eligible for registry in the official herd book of that breed.

Qualitative traits - Those traits in which there is a sharp distinction between phenotypes, such as black and white or polled and horned. Usually, only one or few pairs of genes are involved in the expression of qualitative traits.

Quantitative trait locus (QTL) - Area of a chromosome at which exists a gene that has a direct effect on a quantitative trait of interest. Similar to economic trait locus (ETL), except that QTL refers only to quantitative traits.

Random mating - A system of mating where every cow and (or) heifer has an equal or random chance of being assigned to any bull used for breeding in a particular breeding season. Random mating, or an adjustment for the genetic potential of mates, will reduce bias in a progeny test.

Rate of genetic improvement - Amount of improvement per unit of time (year) due to selection. The rate of improvement is dependent on: (1) heritability of traits considered; (2) selection differentials; (3) genetic correlations among traits considered; (4) generation interval in the herd; and (5) the number of traits for which selections are made.

Reach - See Selection differential.

Recessive gene - A gene whose effect is masked by the presence of a dominant allele. Recessive genes affect the phenotype only when present in a homozygous condition. Recessive genes must be received from both parents before the phenotype caused by them can be observed.

Reference sire - A bull designated to be used as a benchmark in progeny testing other bulls (young sires). Progeny by reference sires in several herds unable comparisons to be made between bulls not producing progeny in the same herd(s).

Regression (regressed) - A measure of the relationship between two variables. The value of one trait can be predicted by knowing the value of the other variable. For example, easily obtained carcass traits (hot carcass weight, fat thickness, rib-eye area, and percent of internal fat) are used to predict percent cutability. Likewise, breeding value estimates based on limited data are regressed back toward the population average to account for the imperfection of the relationship between parent and offspring.

Rib-eye area (REA) - Area of the longissimus muscle measured in square inches at the 12th rib interface on the beef forequarter.

Rotational crossbreeding - Systems of crossing two or more breeds where the breed of sire is rotated in a systematic fashion. In a conventional rotation, sire breeds are rotated each generation to that females are mated to sires of the breed least represented in their own genotypes. Rotation systems maintain relatively high levels of heterosis and produce replacement heifers from within the system.

Scrotal circumference - A measure of testes size obtained by measuring the distance around the testicles in the scrotum with a circular tape. Related to semen-producing capacity and age at puberty of female sibs and progeny.

Scurs - Horny tissue of rudimentary horns that are attached to the skin rather than the bony parts of the head.

Seedstock breeders - Producers of breeding stock for purebred and commercial breeders. Progressive seedstock breeders have comprehensive programs designed to produce an optimum or desirable combination of economical traits (genetic package) that will ultimately increase the profitability of commercial beef production.

Selection - Causing or allowing certain individuals in a population to produce more offspring than others in the next generation.

Selection differential (Reach) - The difference between the average for a trait in selected cattle and the average of the group from which they came. The expected response per generation from selection for a trait is equal to selection differential times the heritability of the trait.

Selection index - A formula that combines performance records from several traits or different measurements of the same trait into a single value for each animal. Selection indexes weigh the traits for their relative net economic importance and their heritabilities plus the genetic associations among the traits.

Sibs - Brothers and sisters of an individual.

Sire summary - Published data on sires from national cattle evaluation programs.

Sperm - A mature male germ cell.

Standardized Performance Analysis (SPA) - Program to determine the commercial and seedstock, cow-calf enterprise, unit cost of production.

Straightbreeding - The mating of animals within a recognized breed, or matings between animals that are similar in breed type, as in grading-up program.

Superovulation - Process by which a cow produces more eggs than normal. Done in embryo-transfer techniques.

Systems approach - An approach to evaluate alternative individuals, breeding programs, and selection schemes that involves assessment of these alternatives in terms of their net impact on all inputs and out put in the production system. This approach specifically recognizes that intermediate optimum levels of performance in several traits may be more economically advantageous than maximum performance for any single trait.

Tandem selection - Selection for one trait at a time. When the desired level is reached in one trait, then selection is practiced for a second trait.

Terminal sires - Sires used in a crossbreeding system where all their progeny, both male and female, are marketed. For example, F₁ crossbred dams could be bred to sires of a third breed and all calves marketed. Although this system allows maximum heterosis and complementarity of breeds, replacement females must come from other herds.

Trait ratio - An expression of an animal's performance for a particular trait relative to the herd or contemporary group average. It is usually calculated as:

           Individual Record                X    100
  Average of Cattle in Group

Transgenic - An organism or animal whose genome includes "foreign" genetic material. Foreign genetic material would be a DNA sequence or gene that does not normally occur in the species of the host organism or animal.

Ultrasonic measurements - used to estimate carcass and reproductive characteristics. Operates on the principle that sound waves echo differently in tissues that have different densities.

USDA Beef Carcass Evaluation Service - Program whereby producers, for a fee, can obtain carcass data on their cattle.

USDA Quality Grade - A grade (e.g., Prime, Choice, Select, etc.) assigned by a Federal grader to predict the palatability of eating characteristics of the meat. The primary components are maturity and marbling score. Texture, firmness and color of the lean are also considered.

USDA Yield Grade - Measurements of carcass cutability categorized into numerical categories with 1 being the leanest and 5 being the fattest. Yield Grade and cutability are based on the same four carcass traits.

Variance - Variance is a statistic that describes the variation we see in a trait.

Weight per day of age (WDA) - Weight of an individual divided by days of age.