Reproductive performance of ewes mated on lucerne
G.H. Scales, R.A. Moss and R.W. Kelly
Winchmore Irrigation Research Station, Ashburton
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Proceedings of the New Zealand Society of Animal Production. 1977, 37: 152-57
The reproductive performance of ewes mated on either lucerne or
ryegrass-clover pastures was compared in 1975 and 1977. Phyto-oestrogens
(coumestans) were present in lucerne but not ryegrass-clover pastures.
In all experiments ewes flushed and mated on lucerne produced fewer
lambs than ewes mated on grass, the difference varying between 16.4 and
37.8%. Reduced twinning (13.7 to 32.3%) accounted for most of this
difference. Barrenness and mean lambing dates were similar for both
treatments.
Ovulation rates as determined by either laparoscropy or slaughter were
12 to 24% lower in ewes mated on lucerne than on ryegrass-clover
pastures in 1977. Embryonic mortality was not significantly increased by
the pasture treatments. It was concluded that the effect on lambing
performance of mating ewes on lucerne containing coumestans is due to a
depression in ovulation rate.
Keywords: NZSAPAB;
Last Updated 24-08-2000
