Animal Science, Department of
Date of this Version
10-1990
Citation
MP56. Institute or Agriculture and Natural Resources
Abstract
A two-year study tested the hypothesis that growth rate interacts with bull exposure to influence age at puberty in heifers. Heifers exposed to sterile bulls and fed to achieve a high growth rate (1.8 lb/day) attained puberty 73 days earlier than heifers not exposed to bulls and fed to a moderate growth rate (1.3 lb/day). Heifers exposed to bulls and fed to achieve a moderate growth rate attained puberty at ages similar to heifers not exposed to bulls and fed to a high growth rate. Furthermore. heifers receiving these two treatments attained puberty 23 days earlier than heifers not exposed to bulls and fed to a moderate growth rate. Pregnancy rates to artificial insemination were higher in heifers exposed to sterile bulls when compared to heifers not exposed to bulls irrespective of growth rates. Therefore. the stimulatory injluencesofbull exposure interacts with growth rate to hasten the onset of puberty in heifers. Also. an increased proportion of heifets became pregnent early in the breeding season when heifers attained puberty at younger ages.
Included in
Large or Food Animal and Equine Medicine Commons, Meat Science Commons, Veterinary Preventive Medicine, Epidemiology, and Public Health Commons
Comments
Used by permission.