tailieunhanh - Báo cáo khoa hoc:" Selection for litter size in pigs. II. Efficiency of closed and open selection lines"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học thế giới đề tài: Selection for litter size in pigs. II. Efficiency of closed and open selection lines | Genet Sei. Evol. 33 2001 515-528 INRA EDP Sciences 2001 515 Original article Selection for litter size in pigs. II. Efficiency of closed and open selection lines Gérard Boleta Jean-Pierre Bidanelb Louis Ollivierb a Institut national de la recherche agronomique Station d amelioration génétique des animaux 31326 Castanet-Tolosan Cedex France b Institut national de la recherche agronomique Station de génétique quantitative et appliquée 78352 Jouy-en-Josas Cedex France Received 17 July 2000 accepted 27 April 2001 Abstract - a selection experiment on litter size in the pig was carried on for seventeen generations in an Inra experimental herd. The founder population was made up of 10 males and 120 females from the Large White breed. Selection was first performed for ten generations in a closed line compared to a control line derived from the same founder population. Selection was carried on within sire family on the total number of piglets born in the first two litters of the dam TB1 TB2 . After ten generations the selection criterion became dam TB1 only. The control line was then discontinued and a panel of frozen semen from the 11th generation boars was created for later comparisons. The selected line was opened to gilt daughters of hyperprolific boars and sows at a rate of 1 8 per generation and the same selection procedure was applied irrespective of the origin of the gilt. During the whole experiment the number of ova shed OS and the number of live embryos LE at 30 days in the 3rd pregnancy were recorded. These two parts of the experiment were analysed using REML estimation of genetic parameters and a BLUP-Animal Model in order to estimate the responses to selection. Significant heritabilities for TB1 TB2 OS and LE were obtained . and respectively. Significant common environment variances and covariances were estimated for nearly all traits. Significantly positive BLUP responses per generation were observed from GO to G17 for TB1 TB2 .