Abstract

Immunisation is a potentially profitable technique to improve ovine fecundity. It increases the proportion of multiple bearing ewes and lambs born as multiples. This calls for adequate feeding if production is to be sustained. The technique is therefore likely to have higher net returns in areas with ample summer feed. AS the response to the treatment is variable, the probability of not breaking even with the cost of the drug can be as high as 30%. Where feed is adequate additional net returns of $1 to $2 per ewe can be expected if the response is a 25% increase in lambs born per ewe joined.

WH, McMillan, and JF Smith

Proceedings of the New Zealand Society of Animal Production, Volume 45, , 187-189, 1985