Age and Weight at Puberty in Hereford Heifers

Abstract

A 2-year study of factors affecting age and weight at puberty in Hereford heifers showed that the year of birth did not affect the two traits. Sires significantly influenced age and weight at puberty with weight being more important than age. Sire-group correlation of age at puberty between years was low while that of weight was relatively high but both were not significant with the small number of sires available for analysis. Day of birth within the year had a significant effect on age and weight at puberty. Heifers born late in the calving season were lighter and younger at puberty. High preweaning growth rate and heavy weaning weights were associated with early puberty and heavy weight at puberty. Data indicate that heifers did not reach puberty until they started to make faster weight gains after the slow winter growth. The faster growing heifers were heavier and older at puberty. Heritability estimates of age and weight at puberty could not be estimated reliably because of random effects and small numbers of sires and small numbers of heifers per sire-group. Copyright © 1971. American Society of Animal Science . Copyright 1971 by American Society of Animal Science.