D

DIM See days in milk. 
DIP Degradable intake protein. That protein or nitrogen degraded in the rumen by micoorganisms into microbial protein or freed as ammonia.
DM See dry matter. 
DMI Dry matter intake. 
DNA See deoxyribonucleic acid. 
Dairy cattle breed Group of dairy cattle having a common origin and identifiable traits (frequently color). The major U.S. breeds are Ayrshire, Brown Swiss, Guernsey, Holstein, Jersey and Milking Shorthorn.
Dairy character Physical traits that suggest high milking ability. Important indications of this include an alert, feminine head; long thin neck; openness and sharpness throughout; prominent hips and pins; sharp withers; thin thighs; flat flinty bone; and thin, pliable hide with a soft silky hair coat. See bloom.
Dairy cow A bovine from which milk production is intended for human consumption, or is kept for raising replacement dairy heifers.
Dairy goat Any goat from which milk production is intended for human consumption, or is kept for raising replacement dairy kids.
Dairy goat breed Group of dairy goats having a common origin and identifiable traits (frequently color). The major U.S. breeds are Alpine, LaMancha, Nubian, Oberhasli, Saanen and Toggenberg.
Dairy Herd Improvement (DHI) Official DHI type of testing plan that requires supervision and compliance with all Official DHI Rules (DHI abbreviation is used commonly to designate the testing plans).
DHI records Generic term used to classify any records computed by the Dairy Record Processing Centers. 
DHI supervisor An officially trained and DHIA-certified employee qualified to collect milk samples and record milk weights for all official types of testing plans.
Dairy Herd Improvement Association (DHIA) An organization with programs and objectives intended to improve production of dairy cattle and profitability of dairy farming and especially to aid dairy farmers in keeping milk production and management records.
Dairy Herd Improvement Registry (DHIR) A modification of the DHIA program to make milk production records acceptable by dairy breed associations. An official production record program. Abbreviation used to designate Official DHIR type of testing plan for registered cows. Record supervision and verification are required in compliance with Official DHI and DHIR rules.
Dairy Records Processing Center (DRPC) A computing facility where information from the periodic tests in NCDHIP herds is summarized and analyzed and where information to be used in future management decisions is prepared for the dairy producer.
Dam The female parent of any dairy animal. 
Daughter-herdmate comparison Amount by which a daughter of a bull differs in yield or other traits from the average of cows of other bulls' daughters of the same breed in the same herd during the same period.
Days dry As used in DHIA records, this is the number of days dry prior to calving at the start of the production record listed.
Days in milk (DIM) The number of days during the present lactation that the cow has been milking, beginning with the last date of calving to the current test date.
Degraded intake protein See DIP. 
Dehorn To remove horns from animals or to treat young animals so horns will not develop. 
Denitrification The chemical or biological reduction of nitrate or nitrite to gaseous nitrogen, either as molecular nitrogen (N2) or as an oxide of nitrogen (N2O).
Deoxyribonucleic acid (DNA) The chemical substance that is the principal nuclear material of cells. The structure of DNA determines the structure of ribonucleic acid which, in turn, determines the structure of proteins of the cell.
Dicoumarol A chemical compound found in spoiled sweet clover and lespedeza hays. It is an anticoagulant and can cause internal hemorrhages when ingested by cattle.
Digestible energy (DE) That portion of energy of a feed that can be digested or absorbed into the body by an animal.  
Digestible protein (DP) The amount of protein of feed that is absorbed by the digestive tract; it may be computed using the formula: Percent DP = percent crude protein of feed x digestion coefficient for protein in the feed.
Digestibility That percentage of food ingested which is absorbed into the body as opposed to that which is excreted as feces.
Digestion coefficient The digestion coefficient of feed ingredients (DCFI) may be calculated using the formula: Wt. of ingredient consumed -- Wt. of undigested ingredient in feces
DCFI = Wt. of ingredient consumed X 100 
Direct microscopic somatic cell count (DMSCC) Microscopic count of the actual number of somatic cells in milk. (This system is used to check and verify electronic cell count machines used in DHI laboratories.)
Disallowed practices Certain procedures or practices that may impair or attempt to impair the reliability of any Official DHI record.
Diuretic A drug or agent used to increase flow of urine. 
Docking Removing the tail for sanitation purposes. 
Doe A sexually mature female goat. 
Doeling A female goat from one to two years old, or from one year old until first parturition. 
Dominant Describes a gene that covers up the physical expression of its paired allele or recessive gene. For example, black-and-white, Holsteins (B) is dominant over red-and-white (b). Thus, BB and Bb Holsteins are black-and-white, whereas bb individuals are red-and-white.
Donor dams Genetically superior cows from which embryos are collected and transferred to recipients to allow these cows to produce a greater number of offspring than possible in a normal reproduction scheme.
Double standardization This refers to standardization of milk for both fat and nonfat solids (or protein). 
Dried milks Dried milk is made from whole milk; nonfat dry milk is manufactured from skim milk. In drying milks, about 95 to 98 percent of the water is removed by concentrating the solids in vacuum pans and then drying by spraying milk into a chamber of hot air or onto a slowly revolving heated drum under vacuum.
DRPC see Dairy Records Processing Center. 
Dry Describes a nonlactating female. The dry period of cows is the time between lactations (when a female is not secreting milk).
Dry cow Any cow that has calved once and is not producing milk. 
Dry date First calendar day the cow is not milked (See dry period). 
Drylot A relatively small area in which cattle are confined indefinitely as opposed to being allowed to have free access to pasture.
Dry matter (DM) The moisture-free content of feeds. 
Dry off To change a lactating animal to a nonlactating one. Usually done 6 to 8 weeks prior to freshening. See involution.
Dry period Nonlactating days between lactations. This nonlactating time is generally a 5- to 6-week rest period before freshening.
Dyspnea Difficult or labored respiration. 
Dystocia Abnormal or difficult labor (parturition), causing difficulty in delivering the fetus and placenta.