Proceedings of the New Zealand Society of Animal Production. 1995,
55: 199-201
Proceedings of the New Zealand Society of Animal Production. 1995,
55: 199-201
One hundred and sixty previously undrenched ewe lambs were randomised into 6 treatments (n=25) on the basis of liveweight (mean 29kg; SD 4.4kg) and FEC (mean 1403epg; SD 1356epg). Ten lambs within each treatment were drenched fortnightly, 15 were not. Lambs were weighed, faecal sampled and given a new break of feed every seven days. An additional 10 lambs were slaughtered at the start to provide measurements of initial worm burden.
Drenched lambs grazing lurcerne had the highest LWG (243g/day) and plantain the lowest LWG (51.2g/day). Undrenched lambs had lower LWGís than the drenched lambs, ranging from 175g/day when grazing sulla, to a small loss of 2g/day while grazing plantain. Wool growth followed a broadly similar pattern. FEC;s were lowest in lambs grazing sulla and highest in lambs grazing plantain. Total worm burdens were lowest in the lambs grazing sulla and highest in lambs grazing maku. Undrenched lambs grazing maku had much lower dry dag weights than those on the other herbages, with those on ryegrass/white clover having the highest.
The high production level obtained in lambs grazing sulla and maku, despite the high worm burdens indicates that these herbages could be used within farm grazing rotations to reduce anthelmintic usage. The marked reduction in dag weights on maku may also be of economic benefit by reducing the need for crutching and the risk of flystrike.
Keywords: NZSAPAB; lambs; internal parasites; specialist crops; production
