Strategic Breeding for Parasitic Resistance in Sheep

Gastrointestinal nematodes (GINs) present a major challenge to global sheep and small ruminant production, with infections from parasites such as Haemonchus contortus leading to considerable economic losses. Dependence on anthelmintics has led to drug-resistant nematodes, underscoring the need for sustainable alternatives. Breeding for genetic resistance is a promising strategy, leveraging natural variation in resistance across sheep breeds. An integrated approach combining selective breeding, improved grazing practices, nutrition, and targeted anthelmintic use is key. Selection focuses on traits such as growth rate under parasite challenge, faecal egg count (FEC), and anaemia indicators. Ultimately, breeding for resistance offers lasting resilience against nematodes, reducing reliance on anthelmintics and minimizing pasture contamination in affected areas.