Production characters of primiparous females of a five-breed diallel.

Abstract

Data included pubertal, reproductive and lactation records of primiparous females produced in a diallel of Angus, Brahman, Hereford, Holstein and Jersey. Brahman heifers were oldest, tallest and heaviest at puberty, while Jersey heifers were youngest, shortest and lightest. Crossbred heifers were 22 d younger (P less than .01) at puberty than straightbred heifers; no significant differences were detected between the two groups for weight or height at puberty. Dairy heifers (Holstein and Jersey) required fewer services (P less than .05) to conception than beef heifers. The difference between straightbred and crossbred heifers for number of services to conception was small and nonsignificant. Rank of straightbreds for age at conception was similar to their rank for age at puberty except that Holstein required 1.2 fewer services and were younger at conception than Jersey. Crossbreds were 41 d younger (P less than .05) at conception than straightbreds. Brahman had the longest gestation length and were oldest at first calving; Jersey had the shortest gestation length and Holstein were youngest at first calving. Straightbred heifers gestated 1.3 d longer and were 45 d older (P less than .05) at first calving than crossbred heifers. Dairy females had greater peak and total milk yield than beef females (P less than .01). Overall straightbred and crossbred means for peak milk yield and total milk yield did not differ significantly.