Abstract

Thirty-eight adult Merino breeding ewes were drenched with Ivomec and given a controlled release anthelmintic (benzimidazole) capsule in August 1992 and December 1993. Mean FEC in the Untreated group peaked over lambing at 600epg in 1992 and 800epg in 1993. Mean FEC in the Treated group remained below 50epg during the active period of the capsule. The Treated ewes had a higher survival rate, were heavier, grew more wool from late July 1993 and weaned more and heavier lambs in 1993 than the Untreated ewes. At a mean Merino wool price of 500c/kg greasy, returns from the increased wool production more than equates with the anthelmintic treatment cost. Increased returns would be gained from improve ewe survival and increased lamb production.

MD, Bown, JB Clayton, WH McMillan, and DC Smeaton

Proceedings of the New Zealand Society of Animal Production, Volume 55, , 161-164, 1995