Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học thế giới đề tài: Genetic and environmental effects on semen traits in Lacaune and Manech tête rousse AI rams | Genet. Sel. Evol. 39 2007 405-419 INRA EDP Sciences 2007 DOI gse 2007011 Available online at Original article Genetic and environmental effects on semen traits in Lacaune and Manech tête rousse AI rams Open Access publication Ingrid DAVIDa Xavier DRUARTb Gilles LAGRIFFOULc Eduardo MANFREDIa Christèle ROBERT-GRANIẾa Loys BODINa a Station d amelioration génétique des animaux INRA UR631 BP 52627 31320 Castanet-Tolosan Cedex France b Physiologie de la reproduction et des comportements INRA - CNRS UMR1291 37380 Nouzilly France c Institut de l Élevage ANIO BP 42118 31320 Castanet-Tolosan Cedex France Received 4 May 2006 accepted 22 February 2007 Abstract - Data from 51 107 and 11 839 ejaculates collected on rams of the Lacaune and Manech tête rousse breeds respectively were analysed to determine environmental and genetic factors affecting semen production traits ejaculate volume semen concentration number of spermatozoa and motility in young 1 year and adult 2 years rams. Fixed effects and variance components were estimated using multiple trait animal models within each breed. For all traits the main environmental effects identified were year season number of ejaculations daily variation interval from previous to current collection and age. Heritability estimates were moderate for volume concentration and number of spermatozoa to and lower for motility to . Genetic correlations between ages differed from 1 for all traits to indicating that semen characteristics corresponded to different traits in young and adult rams. Genetic and phenotypic correlations among traits within age category were globally similar for the different breeds and categories of animals. ram semen environmental factor 1. INTRODUCTION In the ovine species more than 800000 artificial inseminations AI are performed each year in France with fresh semen. The insemination technique is used during a limited period of the year therefore semen .
