Abstract

Young Merino wethers (n=240) were allocated to 1 of 8 treatments in a replicated field experiment. Animals grazed semi-improved pasture and received supplements for 14 or 28 weeks based on fish meal (F14, F28), sunflower meal (S14, S28) or oat grain (O14, O28). Unsupplemented parasite-free (C-) and parasitised animals (C+) were included as controls. Animal performance and parasite status were evaluated. During weeks 1-14 faecal egg counts (FEC) were below 120 eggs per gram (epg), due to low larval intake from pasture. Cumulative live-weight gain (LWG) over this period was increased as a result of supplementary feeding from 8.6 (mean C- and C+) to 11.4 kg (F14; P<0.01) or 9.9 or 9.7 kg (S14 and O14 respectively; P>0.05). From week 15 animals were dosed fortnightly with 6000 Trichostrongylus colubriformis and 2000 Haemonchus contortus larvae. Lucerne hay was fed twice weekly from week 17 onwards (2 kg/sheep/week). The FEC increased to about 5900 epg in week 28 for groups C+, F14, S14, O14 and O28 and about 3000 epg for groups F28 and S28 (P<0.05). Cumulative LWG from weeks 15-28 for groups C-, F28, S28 and O28 (0.9, 1.1, 0.6 and 1.4 kg respectively) was higher than for groups C+, F14, S14 or O14 (-1.2, -1.7, - 2.2 and -0.9 kg respectively; P<0.05). Supplementation with F, S and O during parasite infection enhanced the resilience of grazing sheep to gastrointestinal nematodes, while supplementation with F and S appear to have reduced peak FEC.

MFJ, Van Houtert, IA Barger, and JW Steel

Proceedings of the New Zealand Society of Animal Production, Volume 56, , 94-98, 1996