Heterosis in Preweaning Traits of Beef Cattle

Individual and Maternal Additive and Heterotic Effects on 205-Day Weight in Beef Cattle

“…Somewhat smaller estimates of individual heterosis for weaning weight were reported by Damon et al (1959). However, most of the estimates of individual heterosis reported for British breed crosses have been greater than that observed in this study (Gregory et al, 1965(Gregory et al, , 1978aRollins et al, 1969;Long and Gregory, 1974;Smith et al, 1976;Gray et al, 1978).…”

“…The Polled Hereford maternal additive effect was less (P<.01) than that of the Shorthorn and Hereford. Numerous reports have documented the maternal superiority of the Angus over the Hereford breed of dam (Gregory et al, 1965(Gregory et al, , 1978a(Gregory et al, , 1979Smith et al, 1976). Notter et al (1978) observed no significant differences in weaning weights of calves out of Hereford-Charolais and Angus-Charolais cross cows.…”

Effects of breed, age of dam, birth year, birth season and sex on weaning weight of beef calves

“…Growth of calves and their weaning weight tends to have low heritability (h 2 = 0.12-0.27) and is influenced by a number of environmental effects, including dam's age, year and season of birth and the sex of calves (Gregory et al, 1965(Gregory et al, , 1979Smith et al, 1976;Bö lcskey, 1987;Nelsen and Kress, 1981 Pell and Thayne, 1978;Szabó and Gajdi, 1993;Szabó et al, 2003;TIzsér et al, 1996;Gáspárdy et al, 1998;Jakubec et al, 2000;Lengyel et al, 2003). However, there are contradictory results for the effects of different factors in the various cited reports.…”

Homogametic Heterosis in Crossbreeding Experiments With Sheep

“…In the F, no marked differences in heterosis in wean- The hypothesis explains the difference in heterosis between sexes as a result of the differences in sex chromosomes and is suppo,rted by reports of other work (2,3,7,18) As performance data of pure Cheviots were no,t available, the heterosis of the three-breod cross was measured in terms of the superiority of the cross over the breed of the dam. Johansson and Rendel ( 11) Differences between sexes in heterosis might be comparable with se,x differences in fitness.…”