TERMS TO KNOW
Average Daily Gain (ADG): Measurement of daily body weight change in animal on a feed test. Most tests for bulls are 140 or 160 days long.
Artificial Insemination (AI): The technique of placing semen from the male in the reproductive tract of the female by means other than natural service.
Balance: The harmonious relationship of all body parts, blended for symmetry and appearance. A steer that is poorly developed in the hindquarter lacks balance.
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.
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 should vary among breeders due to relative genetic merit of their cattle, their resources and their markets.
Bull: An uncastrated male of any age.
Calf: A young animal of either sex, under 1 year of age.
Calving Season: The season(s) of the year when the calves are born. Limiting calving seasons is the first step to performance testing the whole herd, accurate records, and consolidated management practices.
Castrate: To remove the testes.
Characteristic: A physical or behavioral trait in an animal. Condition: The degree of fatness in animals.
Conformation: The general structure and shape of an animal.
Cryptorchid: A male bovine with one or both testes undescended.
Culling: The process of eliminating less productive or less desirable cattle from a herd.
Genetic Correlations: Correlations between two traits that arise because some of the same genes affect both traits. When two traits (i.e., weaning and yearling weight) are positively and highly correlated to one another, successful selection for one trait will result in an increase in the other trait. When two traits are negatively and highly correlated (i.e., birth weight and calving ease) to one another, successful selection for one trait will result in a decrease in the other trait.
Genotype: Actual genetic makeup, or constitution, of an individual determined by its genes or germplasm. For example, there are two genotypes for the polled phenotype [PP (homozygous dominant) and Pp (heterozygous)].
Genotype-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.
118 TEXAS LONGHORN JOURNAL i JULY 2017
Environment: All external or non-genetic conditions that influence the reproduction, production, and carcass merit of cattle.
Estrus: The period when a cow will accept a bull for breeding, heat period.
Feed Conversion (Feed Efficiency): Units of feed consumed per unit of weight gained. Also the production (meat, milk) per unit of feed consumed.
Fertility Test: Analysis of semen for live sperm count, tests a bull’s ability to produce offspring.
Finish: The degree of fatness.
Freemartin: Female born twin to a bull calf (approximately 9 out of 10 freemartins will not conceive).
Generation Interval: Average age of the parents when the offspring destined to replace them are born. A generation represents the average rate of turnover of a herd.
Genes: The basic units of heredity that occur in pairs and have their effect in pairs in the individual, but which are transmitted singly (one or the other gene at random of each pair) from each parent to offspring.
Get: Calves sired by the same bull.
Gonad: The organ that produces the reproductive cells, the testicle in the male and the ovaries in the female.
Herd Sire: The principle breeding bull in a herd.
Heredity: The transmission of genetic or physical traits of parents to their offspring.
Heritability: The proportion of the differences among cattle, measured or observed, that is transmitted to the offspring. Heritability varies from zero to one. The higher the heritability of a trait, the more accurately does the individual performance predict breeding value and the more rapid should be the response due to selection for that trait.
Hooks: Hip bones.
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.
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 and weaning weights below 400 pounds (or those in the bottom 20 percent on weaning weight) and yearling weights below 650 pounds (or those in the bottom 40 percent).
Linebreeding: A form of inbreeding in which an attempt is made to concentrate the inheritance of some 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.
Market Value: The price received for live animals.
Metabolism: The transformation by which energy is made available for body uses.
Optimum Level Of Performance: The most profitable or favorable ranges in levels of performance for the economically
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