The effect of the duration and timing of flushing on the ovulation rate of ewes

J.F. Smith, K.T. Jagusch, P.A. Farquhar

Ruakura Animal Research Station, Ministry of Agriculture and Fisheries, Hamilton

Proceedings of the New Zealand Society of Animal Production. 1983, 43: 13-16

In each of 2 years Coopworth ewes were randomised to 8 groups which were offered 2 levels of herbage allowance (1.0 and 5.0 kg DM/ewe/d) from mixed pasture for varying periods during the 6 weeks prior to a synchronised mating. The ovulation rates of ewes fed at the lower allowance and then given the higher allowance for periods of 1 or 2 weeks prior to mating were not different from those fed continuously at the lower allowance.

Ewes offered 3 weeks at the higher allowance showed a 25% increase in ovulation rate irrespective of when in the 6 week period this was received. Thus a minimum carry over period of 3 weeks was obtained. A further 30% increase in ovulation rate was obtained when ewes were offered the higher allowance for the full 6 week period. The proportion in ovulation rate was obtained when ewes were offered the higher allowance for the full 6 week period. The proportion of ewes lambing multiples was lower for those receiving <3 weeks high level feeding than for those receiving at least 3 weeks (33.5% v 56.0%; P<0.001), but there was no additional response to feeding at the high level for 6 weeks.

Keywords: NZSAPAB;

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