Breed effects and heterosis in advanced generations of composite populations for birth weight, birth date, dystocia, and survival as traits of dam in beef cattle

摘要: Heterosis effects were evaluated as traits of the dam in F2 progeny F1 dams and F3 4 3 three composite populations beef cattle. Traits included birth weight, date, calving difficulty percentage, survival percentage at birth, 72 h, weaning for calves with different age classes. Breed nine parental breeds (Red Poll [R], Hereford [H], Angus [A], Limousin [L], Braunvieh [B], Pinzgauer [P], Gelbvieh [G], Simmental [S], Charolais [C]) that contributed to (MARC I = 1/4 C, B, L, H, 1/8 A; MARC II G, S, III R, P, A). Among 2-yr-old dams, breed significant but not h weaning. Calf was lowest smallest (less than mu - 1.5 sigma) largest (greater + weight classes did differ among intermediate Calves difficult births significantly heavier (39.6 vs 35.4 kg) had lower (87.1 92.2%) (77.4 85.1%) experience births. greater or equal yr old from all ages, group generally analyzed. Important on dystocia observed independent weight. Effects heterosis each generation population mean populations. Generally, significant. date (earlier) positive retained combined (P .05) expectation based heterozygosity. These results support hypothesis cattle these is result dominance genes.