TAILIEUCHUNG - Báo cáo sinh học: "The effect of improved reproductive performance on genetic gain and inbreeding in MOET breeding schemes for beef cattle"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: The effect of improved reproductive performance on genetic gain and inbreeding in MOET breeding schemes for beef cattle | Genet Sei Evol 1995 27 347-363 Elsevier INRA 347 Original article The effect of improved reproductive performance on genetic gain and inbreeding in MOET breeding schemes for beef cattle B Villanueva1 J A Woolliams2 G Simm1 1 Scottish Agricultural College West Mains Road Edinburgh EH9 3JG 2 Roslin Institute Edinburgh Roslin Midlothian EH25 9PS UK Received 9 November 1994 accepted 6 March 1995 Summary - The effect of improved reproductive techniques on genetic progress and inbreeding was investigated in MOET multiple ovulation and embryo transfer schemes for beef cattle. Stochastic simulation was used to model a closed scheme with overlapping generations. Selection was on a trait measured in both sexes with heritability and was carried out for 25 years. The number of breeding animals was 9 sires and 18 donors. Embryo production was modelled using a Poisson distribution with the parameter distributed according to a gamma distribution. The mean number of transferable embryos per flush and per donor was with a coefficient of variation of and repeatability between flushes of . This model was compared with models used in previous studies fixed number of embryos per flush or variable number of embryos but with zero repeatability between flushes . The coefficient of variation and the repeatability of embryo yield influenced inbreeding rates. The rate of inbreeding was underestimated by up to 17 when variability of embryo production was ignored. Without a constraint on the number of calves born per year improved success rates for embryo collection and embryo transfer technologies led to notable increases in genetic progress. However the rate of inbreeding was also increased with improved techniques. When the number of calves born per year was fixed genetic progress was maintained but inbreeding rates were substantially reduced by up to 11 with improved techniques due to the opportunity of equalizing family sizes. There was no benefit from sexed semen with .

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