TAILIEUCHUNG - Báo cáo sinh học: "Strategies for controlling rates of inbreeding in MOET nucleus schemes"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Strategies for controlling rates of inbreeding in MOET nucleus schemes | 517 Genet Sei Evol 1994 26 517-535 Elsevier INRA Original article __Strategies for controlling rates of inbreeding in MOET nucleus schemes for beef cattle B Villanueva1 JA Woolliams2 G Simm1 1 Scottish Agricultural College West Mains Road Edinburgh EH9 3JG 2 Roslin Institute Edinburgh Roslin Midlothian EH25 9PS UK Received 24 December 1993 accepted 18 May 1994 Summary - A closed MOET multiple ovulation and embryo transfer nucleus scheme with overlapping generations was modelled for beef cattle by stochastic simulation. Selection was carried out for 25 years on a trait measurable in both sexes and with a heritability of . Different strategies to control the rate of inbreeding were investigated 1 decreasing female selection intensity whilst keeping the number of donors constant 2 culling selected animals after having been used for a period of time 3 using more donors 4 using factorial mating designs and 5 selecting on modified indexes. Comparisons among different schemes were made on the basis of equal number of transfers per year. Strategies 1 2 and 3 reduced inbreeding but also reduced response. When the schemes were compared at the same level of inbreeding culling of animals gave higher rates of genetic progress than decreasing selection intensity. Factorial designs decreased the rate of inbreeding by up to 19 in comparison with nested designs with no effect on response. The most successful strategies were those that reduced the emphasis on family information in the selection criterion and especially selection on estimated breeding values obtained by BLUP best linear unbiased prediction using a deliberately increased heritability. With this method it was possible to reduce inbreeding by up to 30 without affecting genetic progress. The reduction in inbreeding with different raised heritabilities averaged 42 and ranged from 26 to 61 . Under all the strategies studied to control inbreeding proportional reductions in rates of inbreeding were always higher .

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