Some factors influencing the growth of lambs on irrigated pasture

S.D. Walker

Winchmore Irrigation Research Station, Canterbury

E-Mail:

Proceedings of the New Zealand Society of Animal Production. 1968, 28: 41-48

Selenium administration to ewes pre-lambing or during lactation gave inconsistent results for increase in lamb growth, but when given to lambs increased liveweight gains were obtained, and these increased in magnitude as the season progressed. Lambs from ewes drenched to control internal parasites prelambing or during lactation did not consistently grow faster than those from untreated ewes. Drenching of suckling lambs did not significantly increase their liveweight gains by the time of weaning, but significant increases in gains often occurred in weaned lambs. It is suggested that in farm practice "strategic" drenching of ewes and suckling lambs on irrigated pasture may be wasteful and should be replaced by treatment based on the level of infestation of parasites.

At the time of late weaning (15 weeks), lambs early weaned at 10 weeks were never heavier than unweaned lambs; they were as heavy only when on high level feeding after weaning. When the trials were closed three months later, there was little difference between early- and late-weaned lambs if feeding after weaning had been at the high level. There were no interactions between level of feeding and control of internal parasites. The results stress the importance of an adequate level of feeding to both suckling and weaned lambs.

Keywords: NZSAPAB;