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abomasum – The fourth stomach compartment of ruminant animals; corresponds to the true stomach of monogastric animals.

absorption – The passage of liquid and digested (soluble) food across the gut wall.

accuracy (ACC) of selection – Numerical value, ranging from 0-1.0, denoting the confidence that can be placed in the expected progeny difference (EPD); e.g., high (³0.70), medium (0.40-0.69), low (£0.40).

ad libitum – Free-choice; allowing animals to eat all they want.

AI – Abbreviation for artificial insemination.

amino acid – An organic acid in which one or more of the hydrogen atoms has been replaced by the amino group (—NH₂). Amino acids are the building blocks in the formation of proteins.

anestrous – Period of time when the female is not in estrus; the nonbreeding season.

antibiotic – A product produced by living organisms—such as yeast—which destroys or inhibits the growth of other microorganisms—especially bacteria.

artificial insemination – The introduction of semen into the female reproductive tract (usually the cervix or uterus) by a technique other than natural service.

artificial vagina – A device used to collect semen from a male when he mounts in a normal manner to copulate. The male ejaculates into this device, which simulates the vagina of the female in pressure, temperature, and sensation to the penis.

as fed – Refers to feeding feeds that contain their normal amount of moisture.

barren – Not capable of producing offspring.

barrow – A male swine castrated before reaching puberty.

beef – The meat from cattle (bovine species) other than calves (the meat from calves in called veal).

bloat – An abnormal condition in ruminants characterized by a distention of the rumen; usually seen on an animal’s upper left side, owing to an accumulation of gases.

boar – (1) A male swine of breeding age. (2) Denotes a male pig, which is called a boar pig.

bovine – A general family grouping of cattle.

boxed beef – Cuts of beef put in boxes for shipping from packing plant to retailers. These primal and subprimal cuts are intermediate cuts between the carcass and retail cuts.

bred – Female has been mated to the male. Usually implies the female is pregnant.

breed – Animals of common origin with characteristics that distinguish them from other groups within the same species.

broken-mouth – Some teeth are missing or broken.

bull – A bovine male. The term usually denotes animals of breeding age.

bullock – A young bull, typically less than 20 months of age.

buttons – May refer to cartilage or dorsal processes of the thoracic vertebrae.

by-product – A product of considerably less value than the major product. For example, in U.S. meat animals, the hides, pelts, and offal are by-products, whereas meat is the major product.

calf – A young male or female bovine animal under 1 year of age.

calve – To give birth to a calf. Same as parturition.

calving interval – The amount of time (days or months) between the birth of a calf and the birth of a subsequent calf, both from the same cow.

canter – A slow, easy gallop.

carbohydrates – Any foods, including starches, sugars, celluloses, and gums, that are broken down to simple sugars through digestion.

castrate – (1) To remove the testicles. (2) An animal that has had its testicles removed.

cecum (plural, ceca) –  A blind pouch at the junction of the small and large intestine. Poultry have two ceca.

cervix – The portion of the female reproductive tract between the vagina and the uterus. It is usually sealed by thick mucus except when the female is in estrus or delivering young.

colic – A nonspecific pain of the digestive tract.

colt – A young male of the horse or donkey species.

commercial – (1) A carcass grade of cattle. (2) Livestock that are not registered or pedigreed by a registry (e.g., breed) association.

compensatory gain – A faster-than-normal rate of gain after a period of restricted gain.

composite breed – A breed that has been formed by crossing two or more breeds.

concentrate – A feed that is high in energy, low in fiber content, and highly digestible.

conception – Fertilization of the ovum (egg).

contemporaries – A group of animals of the same sex and breed (or similar breeding) that have been raised under similar environmental conditions (same management group).

corpus luteum – A yellowish body in the mammalian ovary. The cells that were follicular cells develop into the corpus luteum, which secretes progesterone. It becomes yellow in color from the yellow lipids that are in the cells.

cost of gain – The total cost divided by the total pounds gained; usually expressed on a per-pound basis.

cow – A sexually mature female bovine animal—usually one that has produced a calf.

cow-calf operation – A management unit that maintains a breeding herd and produces weaned calves.

creep – An enclosure into which young can enter to obtain feed but larger animals cannot enter. This process is called creep feeding.

crossbred – An animal produced by crossing two or more breeds.

crossbreeding – Mating animals from genetically diverse groups (i.e., breeds) within a species.

cud – Bolus of feed a ruminant animal regurgitates for further chewing.

cull – To eliminate one or more animals from the breeding herd or flock.

cutability – Fat, lean, and bone composition of meat animals. Used interchangeably with yield grade. (See also yield grade).

cwt – An abbreviation for hundredweight (100 lb).

cycling – Infers that nonpregnant females have active estrous cycles.

dam – Female parent.

dark cutter – Color of the lean (muscle) in the carcass has a dark appearance, usually caused by stress (excitement, etc.) to the animal before slaughter.

dehorn – To remove the horns from an animal.

diet – Feed ingredients or mixture of ingredients (including water) that are consumed by animals.

digestibility – The quality of being digestible. If a high percentage of a given food taken into the digestive tract is absorbed into the body, that food is said to have high digestibility.

digestion – The reduction in particle size of feed so that the feed becomes soluble and can pass across the gut wall into the vascular or lymph system.

DM – See dry matter.

dock – (1) To cut off the tail. (2) The remaining portion of the tail of a sheep that has been docked. (3) To reduce or lower in value.

dominance – (1) A situation in which one gene of an allelic pair prevents the phenotypic expression of the other member of the allelic pair. (2) A type of social behavior in which an animal exerts influence over one or more other animals.

dressing percentage – The percentage of the live animal weight that becomes the carcass weight at slaughter. It is determined by dividing the carcass weight by the liveweight, then multiplying by 100.

drop – Body parts removed at slaughter—primarily hide (pelt), head, shanks, and offal.

drop credit – Value of the drop.

dry (cow, ewe, sow, mare) – Refers to a nonlactating female.

dry matter (DM) – Feed after water (moisture) has been removed (100% dry).

dystocia – Difficult birth.

embryo transfer – The transfer of fertilized eggs from a donor female to one or more recipient females.

endocrine gland – A ductless gland that secretes a hormone into the bloodstream.

EPD – See expected progeny difference.

equine – Refers to horses.

eruction (or eructation) – The elimination of gas by belching.

essential nutrient – A nutrient that cannot be synthesized by the body and must be supplied in the diet.

estrogen – Any hormone (including estradiol, estriol, and estrone) that causes the female to come physiologically into heat and to be receptive to the male. Estrogens are produced by the follicle of the ovary and by the placenta.

estrous – An adjective meaning “heat,” which modifies such words as “cycle.” The estrous cycle is the heat cycle, or time from one heat to the next.

estrous synchronization – Controlling the estrous cycle so that a high percentage of the females in the herd express estrus at approximately the same time.

estrus – The period of mating activity in the female mammal. Same as heat.

ET – Abbreviation for embryo transfer.

evisceration – The removal of the internal organs during the slaughtering process.

ewe – A sexually mature female sheep. A ewe lamb is a female sheep that has not yet attained sexual maturity.

expected progeny difference (EPD) – One-half of the breeding value; the difference in performance to be expected from future progeny of a sire, compared with that expected from future progeny of an average bull in the same test.

farrow – To deliver, or give birth to, pigs.

fat – Adipose tissue.

feed additive – Ingredient (such as an antibiotic or hormonelike substance) added to a diet to perform a specific role (e.g., to improve gain or feed efficiency).

feed bunk – A trough or container used to feed farm animals.

feed efficiency – (1) The amount of feed required to produce a unit of weight gain or milk; for poultry, this term can also denote the amount of feed required to produce a given quantity of eggs. (2) The amount of gain made per unit of feed.

feeder – Animals (e.g., cattle, lambs, pigs) that need further feeding prior to slaughter.

feeder grades – Visual classifications (descriptive and/or numerical) of feeder animals. Most of these grades have been established by the USDA.

fill – The contents of the digestive tract.

filly – A young female horse.

flock – A group of sheep or poultry.

foal – A young male or female horse (noun) or the act of a mare giving birth (verb).

follicle – A blisterlike, fluid-filled structure in the ovary that contains the egg.

follicle-stimulating hormone (FSH) – A hormone produced and released by the anterior pituitary that stimulates the development of the follicle in the ovary.

founder – Nutritional ailment resulting from overeating. Lameness in front feet with excessive hoof growth usually occurs.

frame score – A numerical rating of frame size.

frame size – A measure of skeletal size. It can be visual or by measurement (usually taken at the hips).

gallop – A four-beat gait of the horse in which each of the two front feet and both of the hind feet strike the ground at different times.

gelding – A male horse that has been castrated.

genotype – The genetic constitution, or makeup, of an individual. For any pair of alleles, three genotypes (e.g., AA, Aa, and aa) are possible.

gestation – The time from breeding or conception of a female until she gives birth to her young.

gilt – A young female swine prior to the time that she has produced her first litter.

handmating – Same as hand breeding—bringing a female to a male for service (breeding), after which she is removed from the area where the male is located.

hay – Harvested forage such as alfalfa hay.

heifer – A young female bovine cow before the time she has produced her first calf.

herd – A group of animals. Used for beef and dairy cattle or for swine.

heritability – The portion of the total variation or phenotypic differences among animals that is due to heredity.

heterosis – Performance of offspring that is greater than the average of the performance of the parents. Usually the amount of superiority of the crossbred over the average of the parental breeds. Also referred to as hybrid vigor.

heterozygous – A term designating an individual that possesses unlike genes for a particular trait.

homozygous – A term designating an individual whose genes for a particular trait are alike.

hormone – A chemical substance secreted by a ductless gland. Usually carried by the bloodstream to other places in the body, where is has its specific effect on another organ.

immunity – The ability of an animal to resist or overcome an infection.

implant – To graft or insert material to intact tissues.

inbreeding – The mating of individuals who are more closely related than the average individuals in a population. Inbreeding increases homozygosity in the population, but it does not change gene frequency.

jack – A male donkey.

jenny – A female donkey.

kosher meat – Meat from ruminant animals with split hooves where the animals have been slaughtered according to Jewish law.

lamb – (1) A young male or female sheep, usually less than 1 year of age. (2) To deliver, or give birth to, a lamb.

lambing – Act of giving birth to a lamb. Same as parturition.

legume – Any plant of the family leguminosae, such as peas, beans, alfalfa, and clover.

libido – Sex drive or the desire to mate on the part of the male.

linebreeding – A mild form of inbreeding that maintains a high genetic relationship to an outstanding ancestor.

luteinizing hormone (LH) – A protein hormone, produced and released by the anterior pituitary, that stimulates the formation and retention of the corpus luteum. It also initiates ovulation.

maintenance – A condition in which the body is maintained without an increase or decrease in body weight and with no production or work being done.

marbling – The distribution of fat in muscular tissue; intramuscular fat.

mare – A sexually developed female horse.

melengestrol acetate (MGA) – A feed additive that suppresses estrus in heifers and is widely used in the feedlot industry.

monogastric – Having only one stomach or only one compartment in the stomach. Examples are swine and poultry.

mule – The hybrid that is produced by mating a male donkey with a female horse. Mules are usually sterile.

mutton – The meat from a sheep that is over 1 year old.

nonprotein nitrogen (NPN) – Nitrogen in feeds from substances such as urea and amino acids, but not from preformed proteins.

nonruminant – Simple-stomached or monogastric animal.

nutrient – (1) A substance that nourishes the metabolic processes of the body. (2) The end product of digestion.

offal – All organs and tissues removed from inside the animal during the slaughtering process.

omasum – One of the stomach components of ruminant animals. It has many folds.

on full feed – A term that refers to animals that are receiving all the feed they will consume. See also ad libitum.

open – Refers to nonpregnant females.

ovine – Refers to sheep.

pace – A lateral two-beat gain in which the right rear and front feet hit the ground at one time and the left rear and front feet strike the ground at another time.

pale, soft, and exudative (PSE) – A genetically predisposed condition in swine in which the pork is very light-colored, soft, and watery.

palpation – Feeling by hand.

parity – The number of different times a female has had offspring.

parturition – The process of giving birth.

pay weight – The actual weight for which payment is made. In many cases, it is the shrunk weight (actual weight minus pencil shrink).

pedigree – The record of the ancestry of an animal.

pencil shrink – An arithmetic deduction (percent of liveweight) from an animal’s weight to account for fill.

phenotype – The characteristics of an animal that can be seen and/or measured (e.g., the presence or absence of horns, the color, or the weight of an animal).

photoperiod – Time period when light is present.

pituitary – Small endocrine gland located at the base of the brain.

polled – Naturally or genetically hornless.

Procine stress syndrome (PSS) - A genetic defect in swine inherited as a simple recessive. It is associated with heavily muscled animals that may suddenly die when exposed to stressful conditions. Their muscle is usually pale, soft, and exudative (PSE).

pork – The meat from swine.

postgastric fermentation – The fermentation of feed that occurs in the cecum, behind the area where digestion has occurred.

postpartum – After birth.

postpartum interval – The length of time from parturition until the dam is pregnant again.

pregastric fermentation – Fermentation that occurs in the rumen of ruminant animals. It occurs before feed passes into the portion of the digestive tract in which digestion actually occurs.

pregnancy testing – Evaluation of females for pregnancy through palpation or using an ultrasound machine.

production testing – An evaluation of an animal based on its production record.

progeny testing – An evaluation of an animal on the basis of performance of its offspring.

progesterone – A hormone produced by the corpus luteum that stimulates progestational proliferation in the uterus of the female.

prostaglandins – Chemical mediators that control many physiological and biochemical functions in the body. One prostaglandin (PGF_2α) can be used to synchronize estrus.

protein – A substance made up of amino acids that contain approximately 16% nitrogen (based on molecular weight).

protein supplement – Any dietary component containing a high concentration (at least 25%) of protein.

puberty – The age at which the reproductive organs become functionally operative.

purebred – An animal eligible for registry with a recognized breed association.

quality grades – Animals grouped according to value as prime, choice, etc., based on conformation and fatness of the animals.

ram – A male sheep that is sexually mature.

ration – The amount of total feed fed to an animal over a 24-hour period.

red meat – Meat from cattle, sheep, swine, and goats, as contrasted with the white meat of poultry.

reticulum – One of the stomach components of ruminant animals. It is lined with small compartments, giving a honeycomb appearance.

roughage – A feed that is high in fiber, low in digestible nutrients, and low in energy. Feeds such as hay, straw, silage, and pasture are examples.

rumen – The large fermentation pouch of the ruminant animal in which bacteria and protozoa break down fibrous plant material that is swallowed by the animal; sometimes referred to as the paunch.

ruminant – A mammal whose stomach has four parts (rumen, reticulum, omasum, and abomasum). Cattle, sheep, goats, deer, and elk are ruminants.

rumination – The regurgitation of undigested food and chewing it a second time, after which it is again swallowed.

scours – Diarrhea; a profuse watery discharge from the intestines.

scrotal circumference – A measurement (usually in centimeters or inches) of the circumference of both testicles and the scrotal sac that surrounds them.

scurs – Small growths of hornlike tissue attached to the skin of polled or dehorned animals.

seedstock – Breeding animals; sometimes used interchangeably with purebred.

selection – Differentially reproducing desired traits in a herd or flock.

service – To breed or mate.

shrink – Loss of weight—commonly used to described the loss in liveweight that occurs when animals are marketed or loss in weight from grease wool to clean wool.

sib – A brother or sister.

silage – Forage, corn fodder, or sorghum preserved by fermentation that produces acids similar to the acids that are used to make pickled foods for human consumption.

sire – Male parent.

sow – A female swine that has farrowed one litter or has reached 12 months of age.

stags – Castrated male sheep, cattle, goats, or swine that have reached sexual maturity prior to castration.

stallion – A sexually mature male horse.

steer – A bovine male that was castrated before puberty.

stocker (cattle) – Weaned cattle that are fed high-roughage diets (including grazing) before going into the feedlot.

stud – Usually the same as stallion. Also a place where male animals are maintained (i.e., bull stud).

subcutaneous – Situated beneath, or occurring beneath, the skin. A subcutaneous injection is an injection made under the skin.

superovulation – The hormonally induced ovulation of a greater-than-normal number of eggs.

supplement – A feed used with another feed to improve the nutritive balance of the total ration.

TDN – See total digestible nutrients.

teasing – Bringing the stallion into the presence of the mare to see if she will mate.

terminal sire – The sire used in a terminal crossbreeding program. It is intended that all offspring from a terminal sire be sold as market animals.

total digestible nutrients (TDN) – Includes the total amounts of digestible protein, nitrogen-free extract, fiber, and fat (multiplied by 2.25), all summed together.

ultrasound – A process used to measure fat thickness and rib-eye area in swine and cattle. The machine sends sound waves into the back of the animal and records these waves as they bounce off the tissues. Different wavelengths are recorded for fat than for lean. Also used to diagnose pregnancy.

uterus – That portion of the female reproductive tract where the young develop during pregnancy.

vaccine – A suspension of attenuated or killed microbes or toxins administered to induce active immunity in the recipient.

vagina – The copulatory portion of the female’s reproductive tract. The vestibule portion of the vagina also serves for passage of urine. The vagina also serves as a canal through which young pass when born.

variety meats – Edible organ by-products (e.g., liver, heart, tongue, tripe).

veal – The meat from very young cattle under 3 months of age.

VFAs – See volatile fatty acids.

viscera – Internal organs and glands contained in the thoracic and abdominal cavities.

vitamin – An organic catalyst, or a component thereof, that facilitates specific and necessary functions.

volatile fatty acids (VFAs) – A group of fatty acids produced from microbial action in the rumen; examples are acetic, propionic, and butyric acids.

walk – A four-beat gait of a horse in which each foot strikes the ground at a time different from each of the other three feet.

weaning – Separating young animals from their dams so that the offspring can no longer suckle.

wet – Used to describe a milking female (e.g., wet cow or wet ewe).

wether -  A male sheep castrated before reaching puberty.

winking – Indication of estrus in the mare in which the vulva opens and closes.

withdrawal time – The length of time before slaughter that a drug should not be given to an animal.

withers – Top of the shoulders.

wool – The fibers that grow from the skin of sheep.

yield grades – The grouping of animals according to the estimated trimmed lean meat that their carcasses would provide; cutability.