Evaluation of the growth performance of Brown Swiss, N'Dama and Brown Swiss x N'Dama crossbred genotypes in the humid tropics [Nigeria]
2005
Ozoje, M.O. (University of Agriculture, Abeokuta (Nigeria). Dept. of Animal Breeding and Genetics) | Nwosu, I.C. (Ibadan Univ. (Nigeria). Dept. of Animal Science) | Ngere, L.O. (Ibadan Univ. (Nigeria). Dept. of Animal Science)
Growth performance traits of 549 calves of different genotypes, from a long term crossbreeding programme in a dual-purpose (meat and milk) herd were studied. The effects of genotype (N'Dama, Brown Swiss, F1s, F2s, 25%, 62% and 75% Brown Swiss backcrosses), year of birth, sex and season on growth rate and body weight at birth, weaning and at 365 days of age were studied along with estimated genetic parameters. Genotype significantly (P0.05) affected the studied growth parameters. At birth, Brown Swiss (BS) calves with average weight of 31.50 kg were significantly heavier than N'Dama calves and the various crossbred progenies. Among the crossbreds, F1s weighing 26.02 kg were significantly heavier when compared with F2s, 75%, 62% and 25% Brown Swiss. At weaning, there was no significant difference between average body weight of F1s and Brown Swiss calves, whereas the differences between the Brown Swiss calves and calves of other groups became wider. The weight advantage of F1s and Brown Swiss calves was consistently maintained till yearling age at 365 days. A general heterotic advantage was observed among the crossbred progenies. Individual and maternal heterosis was positive for all traits. Mortality rate was highest among the 75% BS calves. The significant (P0.05) effect of year of birth affected all growth traits. Calves born in the earlier years were significantly heavier than the ones born the latter years. The lowest birth weight was recorded in year 1987, while the heaviest was recorded in 1974. Similar trend was observed at weaning. Calves average daily gains were linearly related to live weight at birth and at weaning. Season significantly (P0.05) affected weight at birth and at weaning. Calves born in the early dry season (October-December) were heavier at birth and at weaning. The estimates of heritability and repeatability were moderately high. The genetic and phenotypic correlations were all positive, ranging from 0.12 to 0.77
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تم تزويد هذا السجل من قبل Istituto di Servizi per il Mercato Agricolo Alimentare