Effects of differential nutrition on the incidence of oestrus
and ovulation rate in Booroola x Romney and Romney ewes
A.J. Allison, R.W. Kelly
Invermay Agricultural Research Centre, Ministry of Agriculture
and Fisheries, Mosgiel
Proceedings of the New Zealand Society of Animal Production.
1979, 39: 43-49
Differential nutrition from April 4 in Romney and ½
Booroola ½ Romney ewes (B x R) 1½ years of age (n = 30)
resulted in substantial liveweight differences. The number of oestruses
was recorded until the end of the breeding season (September), with the
number of ovulations being observed in each animal within a week of
detection of oestrus. B x R ewes were observed in oestrus on average
6.40 times in comparison with 5.64 in Romney ewes (P<0.01). There
were significantly fewer oestruses in ewes subjected to Low Plane
feeding (LP) than in the High Plane (HP) animals. Mean ovulation rates
in HP and LP B x R ewes were 2.04 ± 0.07 and 1.96 ± 0.06 (NS), in
comparison with values of 1.23 ± 0.03 and 1.04 ± 0.03 for HP and LP
Romney ewes, respectively (P<0.01). The results suggest that B x R
ewes may not be as sensitive to nutritionally induced liveweight
differences as are Romney ewes.
Keywords: NZSAPAB;
Last Updated 12-09-1998
