Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Genetic analysis of twinning rate in Israeli Holstein cattle | Genet Sei Evol 1990 22 349-359 Elsevier IN RA 349 Original article Genetic analysis of twinning rate in Israeli Holstein cattle M Ron E Ezra JI Weller Agricultural Research Organization The Volcani Center Institute of Animal Science Bet Dagan 50-250 Israel Received 12 April 1989 accepted 15 May 1990 Summary - Second and third parity twinning rate of Israeli Holsteins was analyzed by linear LM and threshold models TM . Data were 124 553 calving records of daughters of 179 sires. Twinning rates were and for second and third parity respectively. Heritabilities as estimated by REML for the LM analysis and the counterpart of REML for the TM analysis were and . The correlation betwen LM and TM evaluations was . Both distributions of sire evaluations were positively skewed but only the LM distribution differed significantly from normality. Heritability as estimated from the maternal grandsire effect on twinning rate correlations between sire and maternal grandsire evaluations intraclass correlations among half-brothers and son-sire regressions were all consistent with the hypothesis of polygenic additive inheritance. Sire evaluations for twinning rate were economically favorably correlated with evaluations for dystocia. Breeding for twinning rate may be feasible by selection of sires with high repeatability evaluations and will not result in significant undesirable correlated responses. cattle twinning threshold model selection additive inheritance Resume Analyse génétique du taux de gémellité chez les bovins Holstein d Israel. Le taux de gémellité aux deuxième et troisième vélages de vaches Holstein d Israel a été analyse à I aide du modèle linéaire LM et du modele à seuil TM . Les données portent sur 124553 vélages des filles de 179 taureaux. Le taux de gệmẹllite est respectivement de 4 8 et 6 9 au deuxtème et au troisième vélage. L heritabilite est estiméê à 2 2 par la methode du maximum de vraisemblance restreint REML dans I analyse LM et à 10 1 .
