ear mark - Method of permanent identification by which slits or notches are placed in the ear.
ear tag - Method of identification by which a numbered, lettered, and/or colored tag is placed in the ear.
early maturity - Early puberty as the animal begins to fatten early, sometimes before desired slaughter weight is obtained.
EBV - See breeding value; expected progeny difference (EPD).
economic efficiency - Ratio of output value to cost of input.
economic value - The net return within a herd for making a pound or percentage change of the trait in question.
edema - Abnormal fluid accumulation in the intercellular tissue spaces of the body.
efficiency - Ratio of output to input. See also biological efficiency; economic efficiency.
80%-20% rule - Basic rule of management. Too often managers expend 80% of their efforts on "the trivial many" problems that produce only 20% of the results. Effective managers recognize that spending time (20%) on problems or situations that count most, will produce 80% of the desired results.
ejaculation - Discharge of semen from the male.
emaciation - Thinness; loss of flesh such that bony structures (hips, ribs, and vertebrae) become prominent.
embryo - Fertilized egg in its early stages of development; after body parts can be distinguished, it is known as a fetus.
embryo splitting - Dividing an embryo into two or more similar parts to produce several calves from a single embryo.
embryo transfer (ET) - Transfer of fertilized egg(s) from a donor female to one or more recipient females.
Endangered Species Act (ESA) - A regulatory statute intended to protect threatened and endangered species by preserving the ecosystems on which they depend.
endocrine gland - Ductless gland that secretes a hormone into the bloodstream.
energy - Force, or power, that is used to drive a wide variety of systems. It can be used as power of mobility in animals, but most of it is used as chemical energy to drive reactions necessary to convert feed into animal products and to keep the animals warm and functioning.
enterprise - Segment of the cattle business or an associated business that is isolated by accounting procedures so that its revenue and expenses can be identified.
enterprise budget - Detailed list of all estimated revenue and expenses associated with a specific enterprise.
environment - Total of all external (nongenetic) conditions that affect the well-being and performance of an animal.
Environmental Protection Agency (EPA) - Independent agency of the federal government established to protect the nation's environment from pollution.
enzyme - Complex protein produced by living cells that causes changes in other substances in cells without being changed itself and without becoming a part of the product.
EPA - See Environmental Protection Agency.
EPD - See expected progeny difference.
epididymis - Long, coiled tubule leading from the testis to the vas deferens.
epididymitis - Inflammation of the epididymis.
epistatis - Situation in which a gene or gene pair masks (or controls) the expression of another nonallelic pair of genes.
equity - See net worth (equity).
eruction (or eructation) - Elimination of gas by belching.
esophageal groove - Groove in the reticulum between the esophagus and omasum. Directs milk in the nursing calf directly from the esophagus to the omasum.
estrogen - Any hormone (including estradiol, estriol, and estrone) that causes the female to express heat and to be receptive to the male. Estrogens are produced by the follicle of the ovary and by the placenta and have additional body functions.
estrous - Adjective meaning "heat" that modifies such words as cycle. The estrous cycle is the heat cycle, or the 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 - Period of mating activity in the heifer or cow. Same as heat.
ET - See embryo transfer.
ethology - Study of animal behavior.
EU - See European Union.
European breed - Breed originating in European countries other than England (these are called British breeds); a larger dual-purpose breed such as Charolais, Simmental, and Limousin; also called continental or exotic breed in the United States.
European Union - Group of fifteen countries (Austria, Belgium, Denmark, Finland, France, Germany, Great Britain, Greece, Ireland, Italy, Luxembourg, Portugal, Spain, Sweden, and The Netherlands) whose major objective is to coordinate the development of economic activities. Previously called The European Economic community, European community, and Common Market.
eviserate - Removal of the internal organs during the slaughtering process.
Excel - One of the three largest U.S. beef-packing companies.
exotic breed - See European breed.
expected progeny difference (EPD) - One-half of the breeding value of a sire or dam; the difference in expected performance of future progeny of a sire, when compared with that expected from future progeny of bulls in the same sire summary.