Date of this Version
Age at puberty is an important production trait in beef cattle where heifers are bred to calve at 2 years of age, especially when a restricted breeding season is used. It is not only important that heifers breed and conceive, but, for maximum efficiency, they should breed and conceive early in the breeding season. Thus, age at puberty may be an important selection trait for identifying breeds most suited for efficient utilization of feed resources. Several researchers have demonstrated large differences among breed or breed cross in age at puberty of heifers. Other researchers have demonstrated that undernutrition may result in increased age at puberty, subnormal conception rate, and underdeveloped udders. Overfeeding, however,may result in weak heat symptoms, subnormal conception rate, high embryonic mortality, decreased mammary gland development, and decreased milk production. Thus, proper nutrition during the developmental period may have both short and long term effects on heifer productivity. The purposes of the present study were to describe the effects of breed and postweaning growth rate on the onset of puberty, milk production, and productivity of heifers.