Relationships between gastro-intestinal Nematode parasite resistance and other traits of economic relevance in dairy sheep

This project took place at the Research Unit: Genetics and Biotechnology of the Sardinian Agency for Agricultural Research (AGRIS Sardegna, Italy) in Olmedo, and undertook research on relationships between gastrointestinal nematode parasite resistance and other traits of economic relevance in dairy sheep, supervised by Dr. Antonello Carta (


Nematode parasites are one of the major animal health constraints in sheep breeding also with a great impact upon productivity. According to the increasing consumers’ demand of healthy and drug-free products, selection for resistance to disease is a promising approach to obtain healthy products. Evidence for genetic variation amongst sheep in their resistance to gastro-intestinal nematode parasites is well documented in many breeds. Implementation of nematode resistance in breeding programs required the knowledge of the relationships between this health trait and the other traits of economic relevance in dairy sheep.

The project

The Nematode System Health Marie Curie Training Network was a collaborative venture between interested scientists across Europe focused on developing a systems’ based approach to selecting animals that are genetically resistant to disease. The training program brings together expertise in parasitology, genetics, immunology, animal breeding, animal husbandry, animal behaviour, microbiology, statistics, epidemiology and mathematical modelling.

The AGRIS team

The Sardinian Agency for Agricultural Research (AGRIS-Sardegna) is the body of the Sardinian Autonomous Region to be responsible for experiments in agriculture. The Department for Research on Animal Production (before Istituto Zootecnico e Caseario per la Sardegna) is responsible for experiments in livestock and food science. The research unit Genetics and Biotecnology is the scientific reference of the National Breeders Associations for the selection scheme of the Sardinian sheep. In the last years its main topics have been the use of genomic information for selection purposes with main emphasis on disease resistance. In the framework of studying traits related to gastrointestinal parasite infections they have strong links with Prof. Antonio Scala (University of Sassari), one of the main national experts in nematodes studies.


An experimental population was measured for faecal egg count (FEC) under natural conditions of infection as well as for several traits of economic relevance including milk traits, growth and body condition score, fatty acid profile of milk, udder morphology and mastitis resistance. Phenotypic and genetic relationships between gastrointestinal nematode parasite resistance and the other traits were studied by classical quantitative approaches. Moreover all genetic polymorphisms or QTL regions that have been associated with gastro-intestinal nematode parasite resistance were studied for their effects on the other traits with major emphasis on mastitis and paratuberculosis resistance.