Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học thế giới đề tài: Genetic parameters for lactation traits of milking ewes: protein content and composition, fat, somatic cells and individual laboratory cheese yield | 581 Genet. Sel. Evol. 34 2002 581-596 INRA EDP Sciences 2002 DOI gse 2002024 Original article Genetic parameters for lactation traits of milking ewes protein content and composition fat somatic cells and individual laboratory cheese yield Med. Houcine Othmane Juan Antonio Carriedo Fermin San Primitivo Luis Fernando De la Fuente Departamento de Producción Animal I Universidad de León 24071 León Spain Received 12 July 2001 accepted 25 February 2002 Abstract - The effects of some environmental variation factors and the genetic parameters for total milk traits fat content protein content casein content serum protein content lactation mean of individual laboratory cheese yield LILCY lactation mean of somatic cell count LSCC and milk yield were estimated from the records of 1111 Churra ewes. Genetic parameters were estimated by multivariate REML. Heritability for fat content was low as is usually found in the Churra breed. Heritabilities for protein content casein content serum protein content LILCY milk yield and somatic cell count were and respectively. The highest heritability estimates were for protein and casein contents. Casein content is not advisable as an alternative to protein content as a selection criterion for cheese yield improvement it does not have any compelling advantages and its measurement is costly. Our results for LSCC indicated that efforts should focus on improving the level of management rather than selecting for somatic cells in the actual conditions of the Churra breed. dairy ewes casein content individual laboratory cheese yield genetic parameters selection goal Abbreviation key LILCY lactation mean of individual laboratory cheese yield LSCC lactation mean somatic cell count in their natural logarithmic form FYS flock-year-season L30-120 milk yield obtained between 30 and 120 days. 1. INTRODUCTION Interest in research into the yield and composition of milk from small ruminants in general has increased
