Abstract

Finding methods of dealing with increasing levels of anthelmintic resistance is important to the New Zealand sheep industry. Genetic selection within the sheep population for animals that are less reliant on anthelmintic therapy is one approach, and AgResearch has bred selected lines of Romneys over recent decades. These have included lines for resistance and for resilience (Bisset et al., 2001). The resistant line, selected for low faecal egg count (FEC) in lambs, was established in 1979. The line selected for increased resilience in lambs was set up in 1994. Resilience is the ability of animals to maintain acceptable health and growth under high parasite challenge, with minimal need for anthelmintic treatment. We report results here from a study to evaluate sires from these two long-term breeding lines, with progeny measured for weaning weight (WWT) and faecal egg count (FEC) at weaning.

M, Wheeler, CA Morris, and BP Devantier

Proceedings of the New Zealand Society of Animal Production, Volume 69, Christchurch, 228-229, 2009