title: Genetic parameters for lactation traits of milking ewes: protein content and composition, fat, somatic cells and individual laboratory cheese yield.
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 1,111 Churra ewes. Genetic parameters were estimated by multivariate REML. Heritability for fat content was low (0.10) 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 0.31, 0.30, 0.22, 0.09, 0.26 and 0.11, 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.
authors.affiliation: Departamento de Producción Animal I, Universidad de León, 24071 León, Spain.
authors.forename: Med Houcine
authors.initials: MH
authors.lastname: Othmane
authors.forename: Juan Antonio
authors.initials: JA
authors.lastname: Carriedo
authors.forename: Fermin
authors.initials: F
authors.lastname: San Primitivo
authors.forename: Luis Fernando
authors.initials: LF
authors.lastname: De La Fuente
mesh_terms: D000375:Aging; D000818:Animals; D002364:Caseins / Q000032:analysis; D002611:Cheese / Q000032:analysis; D005223:Fats / Q000032:analysis; D005260:Female; D007774:Lactation / Q000235:genetics*; D008892:Milk / Q000737:chemistry* / Q000166:cytology; D008894:Milk Proteins / Q000235:genetics; D010641:Phenotype; D012641:Selection, Genetic; D012756:Sheep / Q000235:genetics* / Q000502:physiology
chemical_list: D002364:Caseins; D005223:Fats; D008894:Milk Proteins