Abstract

Low lambing rates are characteristic of ewe flocks on the summer-dry East Coast. In the present experiment, groups of 4- and 6- tooth 54 kg ewes were either kept on, or transferred between, non-facial eczema-prone (NFE) and facial eczema-prone (FE) stations. Two additional groups on the FE station received weekly dozes of zinc and serial blood sampling of all groups identified ewes with a high threshold resistance to FE. Ewes gained 4 kg in the 8 weeks prior to mating. Groups on the NFE station had 3% barrenness and 55% twinning; those on the FE station had 18% and 38%. Resistance to FE reduced barrenness from 18 to 10% but did not increase twinning. Estimated lambing percentages were 150 on the NFE station, 113 on the FE. The FE factor was associated with some of the barrenness but most of the reproductive loss appeared due to a factor which imitated an oestrogen. The oestrogenic mycotoxin zearalenone, produced by some pasture Fusaria, was detected in pasture samples collected from the FE but not from the NFE station.

HR, Tervit, PG Goold, and RD McKenzie

Proceedings of the New Zealand Society of Animal Production, Volume 46, , 233-236, 1986