Some Factors Affecting Age at Puberty in Holstein-Friesian Heifers

Open Access
Publisher Website
Google Scholar
Abstract
The effects of inbreeding, calfhood scouring, and season of birth on age at 1st heat were studied in 6 sire groups of Holstein-Friesian heifers, totaling 67 animals. No statistically significant differences were found in puberal age among the sire groups. Inbreeding and calfhood scouring were found to delay age at puberty and also to retard calfhood growth signi-ficantly. A highly significant negative correlation was found between age at puberty and wt. at 3 or 6 mos. of age. Adjust-ment of puberal ages for differences in wt at 3 or 6 mos. yielded evidence suggesting that inbreeding or calfhood scouring, or both, increased age at puberty by retarding growth. Heifers born during the spring were found to reach puberty at a signi-ficantly earlier age than those born during other seasons of the year. No evidence was found that age of puberty is associated with the readiness with which heifers conceived.