A Genome scan to detect QTL affecting dairy traits in a dairy sheep backcross Sarda x Lacaune population

Recently in Mediterranean countries as France, Italy and Spain, dairy sheep selection has been efficiently oriented towards milk yield and milk composition. More attention has been now paid to traits related to the reduction of production costs (milkability, functional traits, longevity), health (resistance to mastitis or parasitic diseases), safety of food (reduction in contaminants) and quality (milk fatty acids composition). Therefore, research combining classical quantitative approach and QTL detection is needed, either on-farm by implementing experimental recording schemes, or in experimental flocks especially for traits costly to record. In this framework, two complementary QTL detection projects have been implemented in France and Italy: one based on crossbreeding between Sarda and Lacaune breeds (Cartaet al., 2002) and the other based on purebred granddaughter families of French dairy sheep breeds (Schibleret al., 2002). In this paper, first results of a genome scan based detection of QTL affecting milk traits in first lactation in the Sarda x Lacaune backcross population are presented.