tailieunhanh - Báo cáo khoa hoc:" Genetic analysis for mastitis resistance and milk somatic cell score in French Lacaune dairy sheep"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học thế giới đề tài: Genetic analysis for mastitis resistance and milk somatic cell score in French Lacaune dairy sheep | Genet Sei. Evol. 33 2001 397-415 INRA EDP Sciences 2001 397 Original article Genetic anaÍYSÌs for mastitis resistance and miik somatic ceii score in French Lacaune dairY sheep Francis Barilleta Rachel Ruppb Sandrine Mignon-Grasteaua c Jean-Michel Astrucd Michele Jacquina a Station d amelioration des animaux Institut national de la recherche agronomique BP 27 31326 Castanet-Tolosan Cedex France b Station de génétique quantitative et appliquée Institut national de la recherche agronomique 78352 Jouy-en-Josas Cedex France c Present address Station de recherches avicoles Institut national de la recherche agronomique 37380 Nouzilly France d Institut de 1 élevage BP 18 31321 Castanet-Tolosan Cedex France Received 14 September 2000 accepted 13 February 2001 Abstract - Genetic analysis for mastitis resistance was studied from two data sets. Firstly risk factors for different mastitis traits . culling due to clinical or chronic mastitis and subclinical mastitis predicted from somatic cell count SCC were explored using data from 957 first lactation Lacaune ewes of an experimental INRA flock composed of two divergent lines for milk yield. Secondly genetic parameters for see were estimated from 5 272 first lactation Lacaune ewes recorded among 38 flocks using an animal model. In the experimental flock the frequency of culling due to clinical mastitis 5 was lower than that of subclinical mastitis 10 predicted from sec. Predicted subclinical mastitis was unfavourably associated with the milk yield level. Such an antagonism was not detected for clinical mastitis which could result to some extent from its low frequency or from the limited amount of data. In practice however selection for mastitis resistance could be limited in a first approach to selection against subclinical mastitis using sec. The heritability estimate of sec was for the lactation mean trait and varied from to from the first to the fifth test-day. The genetic correlation between lactation see .