Abstract

Results from farmlet studies indicated that anthelmintic treatment of ewes during pregnancy virtually eliminated ewe parasite faecal egg counts and lead to significantly higher lamb weaning weights. The objective of this study was to develop strategies to enable the rearing of lambs within minimal anthelmintic administration. There were four farmlets, with paired units on dry and irrigated land (5 and 6.4 ha respectively) with mixed aged flocks of 60 or 80 ewes respectively. One flock on each pair of farmlets, termed treated flock, were treated with a continuous anthelmintic release bolus in March prior to mating and again 100 days later in June. The control flock of each pair was given an oral anthelmintic post-lambing in line with local farmer practice. In March of both years faecal egg counts (FEC) were similar for all flocks and averaged between 40 and 160 eggs per gram (peg). For bolus treated flocks average FEC declined to 0 after treatment and remained below 32 peg until September. In contrast the control flocks had significantly higher (P<0.001) egg counts at levels of 50 to 600 epg throughout winter, but exhibited the classic periparturient peak in 1993 only. From October all flocks had similar FEC

, Kusmartono, TN Barry, PR Wilson, PD Kemp, and KJ Stafford

Proceedings of the New Zealand Society of Animal Production, Volume 55, , 169-173, 1995