E

Eartag A tag that generally is attached to the ear of a dairy cow for easy and accurate identification. 
Earthen storage basin An earthen pond or basin for storing animal waste. Difers from an anaerobic treatment lagoon in that wastes are not stored for and extended period and microbial breakdown or treatment does not occur.
Economic indexes PTA Dollars (PTA$), PTA$ Protein and PTA$ Cheese (Cheese Yield$) are economic indexes used in selecting cattle that combine relative values of milk and components.
Edema The presence of abnormally large amounts of fluid in the intercellular tissue spaces of the body, as in swelling of mammary glands commonly accompanying parturition in many farm animals.
Efficacy Effectiveness. 
Effluent The liquid outflow or discharge of a waste treatment process. 
ELUD See extra label use drug. 
Emaciation A wasted condition of the body; great losses of body weight or condition. 
Embryo recipient Any cow or heifer that serves as a surrogate mother and carries the embryo of another cow throughout the development of the embryo and birth of the calf.
Embryo transfer Modern technology whereby multiple fertilized eggs (ova) are flushed from the donor's uterus, and are transferred to a recipient animal that serves as a surrogate mother. The fertilized ova may be frozen and stored indefinitely before they are thawed and transferred to
recipients.
Ensilage A green chop (forage) preserved by fermentation in a silo, pit, or stack, usually in chopped form. Also called silage.
Epidemic The rapid spreading of a disease so that many animals or people have it concurrently. See epizootic. 
Epizootic Designating a widely diffused disease of animals spreading rapidly and affecting many individuals of a kind concurrently in any region, thus corresponding to an epidemic in man.
Equalization fund See producer settlement fund. 
Ergosterol A plant sterol which, when activated by ultraviolet rays, becomes vitamin D2 , also called provitamin D2 and ergosterin.
Eructation The act of belching or casting up gas from the stomach. 
Escutcheon The part of a cow that extends upward just above and back of the udder where the hair turns upward in contrast to the normal downward direction of hair. Also called milk mirror.
Estrus (oestrus, estrous) The recurrent, restricted sexual receptivity (heat) in female mammals, commonly marked by intense sexual urge. Estrous pertains to the entire cycle of reproductive changes in the nonpregnant female animal.
Ether extract (EE) Fatty substances or lipids of foods and feeds that are soluble in ether. 
European breeds Those native to Great Britain or continental Europe such as Charolais, Simmental, Limousin, Jersey, Holstein, and Guernsey.
Evaporated milk The liquid food obtained by partial removal of water from milk. The MF and TMS contents are not less than 7.5 and 25.5 percent, respectively. It contains 25 IU vitamin D per ounce and is homogenized. The food is sealed in a container and is so processed by heat, either before or
after sealing, as to prevent spoilage.
Exocrine (eccrine) Secreting outwardly, into, or through a duct. 
Extra label use drug An antibiotic or other chemical used on the advice of a veterinarian in a dosage, route of administration, for a disease, or in some other manner not included on the approved printed package label.
Extroversion The process of exposure of tissues inside the streak canal of cows' teats. It is usually caused by prolonged milking and excessive milking vacuum or inadequate pulsation.