Animal Science Terms - E

Ear Tag: device, usually a plastic or metal tag, placed in the ears of their animals to identify each individual animal in the herd. The ID information is printed or written on the tag and then it is applied to the ear and allows for the farmer to maintain accurate health and milk production records. It is not considered a permanent method of ID

Effective NDF: measure for ruminant animals of the amount of neutral detergent fibre (NDF) above a minimum feed particle size in their diet

Egg: reproductive cell of most organisms that reproduce sexually. Eggs are haploid (they have half the number of chromosomes as the other cells in the organism’s body. During reproduction, the nucleus of an egg fuses with the nucleus of a sperm cell (the male reproductive cell) to form a new organism with a complete set of chromosomes. Some animals, like cows or humans, keep the egg inside the body as it develops into a fetus. Other animals, like chickens, incubate their eggs outside the body

Embryo: unborn offspring that does not yet have developed organ systems and is in the very early stages of development in the uterus. In animals, this is its earliest stages of development, before all the major body structure are represented. In humans, the embryonic stage lasts through the first eight weeks of pregnancy

Embryo Transfer: removing fertilized ova (embryos) from one cow (the donor), generally in response to hormone-induced superovulation through a process called flushing. Then there is a transfer of these embryos into other cows (the recipients). The embryo is in the is at the blastula stage of development upon transfer. More calves can be obtained from cows of superior breeding value by this technique

Emulsifier: substance added to products to enable fat or oil to remain in liquid suspension; it is commonly added to milk replacers to prevent fat from separating

Endosperm: starchy portion of seed

Ensiled: plant material preserved by anaerobic fermentation and typically stored in a bag, bunker, or upright silo 

Enterotoxemia: disease caused by an overgrowth of bacteria (Clostridia perfringens) in the intestine, usually due to fermentation of a large quantity of starch, with production of endotoxin. Usually causes rapid death of animals

Environment: sum of all external influences to which an animal is exposed to including: climate, housing, feed sources, and disease

Environmental Protection Agency (EPA): many states, the EPA monitors and regulates gas emissions and pollutant discharge from livestock operations

Enzyme: any of numerous complex proteins produced by living cells that speeds up chemical reactions without being changed or destroyed itself. Enzymes are added to animal feeds to supplement low enzyme production or to improve utilization of poorer quality feeds. Enzymes can help break down food during digestion, or they can join nucleotides during the DNA replication process. In humans, the enzyme lactase breaks down the protein lactose found in milk

Epistasis: interaction of two or more pairs of a gene that are not allele to produce a phenotype that they do not produce when they occur separately

Equine: name of the family that includes horses, mules, donkeys and zebras

Erythrocyte: any of the oval or disc-shaped cells that circulate in the blood of vertebrate animals, contain hemoglobin, and give blood its red color. The hemoglobin in erythrocytes binds with oxygen for transport and delivery to body tissues. Also called a red blood cell

Escape protein: see Rumen-undegradable protein

Essential amino acid: amino acids that must be supplied in the diet, as the animal either cannot synthesize them at all or cannot synthesize them in sufficient quantities to meet its requirements

Essential fatty acid: fatty acid that cannot be synthesized by an animal from other sources. Linolenic (18:3n3) and linoleic acid (18:2n6) are essential in the diet; these fatty acids are the basis for the omega-3 and omega-6 classes of fatty acids and are building blocks for longer-chain fatty acids. Fatty acid deficiencies are unusual but can affect skin, coat and reproductive performance 

Estimated crude protein from non-protein source (ECP from NPS): non-protein nitrogen source, such as urea or ammonia; used in ruminant diets in limited amounts to enhance dietary protein levels

Estrogen: hormone that primarily causes behavioral estrus

Estrous: adjective describing anything having to do with the female reproductive cycle, including estrus

Estrous cycle: series of physiological changes that occur in the female of most mammals from one period of estrus to another. The estrous cycle usually takes place during a period known as the breeding season, which ensures that young are born at a time when the chance of survival is greatest

Estrus: regularly recurring period in female mammals during which the animal is sexually receptive. Estrus occurs around the time of ovulation; in heat

Estrus Synchronization: when multiple females in a group go into estrus around the same time. This can be a natural occurrence caused by factors like seasonal changes or the presence of a male

Ether extract: part of a complex organic material that is soluble in ether and consists chiefly of fats and fatty acids. This laboratory test is used to approximate the total fat content of a feed; includes some waxes, pigments and other lipids to a minor degree

Excreta: substances produced by animals as waste after the metabolic process. Urine, fecal matter and carbon dioxide are all excreta

Expanded: condition where feed ingredients, such as corn kernels, are swollen to several times their original size by first steaming under pressure to force moisture into the kernels, and then exposing to air

Expected Progeny Differences (EPDs): provide estimates of the genetic value of an animal as a parent. They are calculated for birth, growth, maternal, and carcass traits and are reported in the same units of measurement as the trait (normally in pounds)

External Parasite: organisms, like fleas, ticks, mites, bot flies, scabies, lice and horse flies, that feed off host animals. These parasites feed on body tissue such as blood, skin cells, sweat, hair, and ocular fluid. The wounds and skin irritation produced by these parasites result in discomfort and irritation to the animal. External parasites are a concern in the animal industry because of their tendency to carry diseases; aso called an ectoparasite

Exotic Species: non-native plant or animal species introduced by humans, either deliberately or accidentally

Extracted: feed condition where fat and oil are removed from a feed or byproduct by heat and mechanical pressure (mechanically extracted) or by organic solvent (solvent extracted).

Extruded: feed condition where ingredients are forced through narrow openings under pressure crushing the individual pieces into much smaller particles

Ewe: female sheep at least 1 year of age

Ewe lamb: female sheep under 1 year of age

 

 

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