Incidence of bearings in ewes that had a bearing the preceding
lambing
A.J. Litherland, M.J. Lambert, T. Knight, T. Cook and D.B. McDougal
AgResearch, Grasslands Research Centre, Private Bag 11008,
Palmerston North, New Zealand
Proceedings of the New Zealand Society of Animal Production.
200 60: 44-46
In the summer of 1998/9, 220 mixed-age breeding ewes were
obtained from eight North Island farms. Half of these ewes had had a
bearing in 1998 (PB ewes) and the other half were flock mates that had
not (NB ewes). Ewes were fed in excess of their requirements from eight
weeks before lambing and ewe condition had increased by 0.4 CS units by
lambing. At scanning 15% of PB ewes were dry compared to 10% of the NB
ewes. Pregnant PB and NB ewes also had similar scanning percentages
(151% vs 142% respectively). Twenty percent of PB ewes had a bearing in
1999 (17% in single and 29% in twin pregnant ewes) compared with 0% in
NB ewes (P<0.001). Pre-lambing bearings occurred 18 ± 2 days (2-33 days)
before lambing. There was a 5% bearing incidence after lambing. Eleven
percent of the ewes treated for bearings died before lambing and 78% of
surviving treated ewes produced a live lamb. In conclusion, high feeding
levels in late pregnancy do not necessarily cause bearings. Ewes with
bearings should be clearly identified and culled as they are more likely
to have bearings the following year.
Keywords: NZSAPAB;
prolapse vagina; nutrition.
Last Updated 12-07-2000
