Use of grade animals in United States Department of Agriculture programs.
Use of records from both registered and grade animals in genetic improvement programs in the United States is summarized. To date, grade bulls have contributed little to genetic improvement in the United States. Grade bulls can contribute significantly only if they are sampled and returned to heavy artificial insemination service. In contrast, grade daughters of registered bulls have contributed extensively to genetic improvement by permitting more bulls to be sampled. Sixty-five percent of daughters with records used to calculate initial proofs of artificial insemination Holstein bulls are grades. Averages for other breeds ranged from 5 to 20%. Implementation of and active participation in provisional registry of grades can result in a moderate increase in genetic improvement in Holsteins. Active participation in provisional registry for other breeds will bring a smaller genetic increase because of fewer grades in those breeds. However, provisional registry programs still can lead to a number of long-range advantages through increasing the population base. There appears to be no scientific basis for not implementing such programs.
D000818:Animals; D001947:Breeding; D002417:Cattle / Q000235:genetics* / Q000502:physiology; D003612:Dairying; D005298:Fertility; D007774:Lactation; D008892:Milk / Q000378:metabolism; D012042:Registries; D014481:United States