title: Vital statistics and reasons for disposal of United States and Canadian artificial insemination dairy sires.
abstract: Vital statistics were evaluated for artificial insemination sires leaving service during 1939 through 1974. Data consisted of 11,704 sires of six breeds. The major cause for leaving service was reproductive failure at a frequency of 32.5%; next ranked was undesirable characteristics of offspring with a frequency of 20.7%. Overall culling rate for low yields of daughters was 14.8%, but after 1965 this cause accounted for about 30%. Mean life span was 3.4 yr with small differences among years. Breed differences were detected for service life and causes for leaving service. Modifications of classic life table techniques are needed to reflect entry of sires into service at various ages and evaluation of vital statistics subsequent to 1974.
mesh_terms: D000367:Age Factors; D000818:Animals; D002170:Canada; D002417:Cattle / Q000235:genetics / Q000502:physiology; D007315:Insemination, Artificial / Q000662:veterinary; D008297:Male; D012098:Reproduction; D014481:United States; D014798:Vital Statistics