Abstract:
Rumen-protected methionine or barley supplements for parasitised Merino lambs F.U. Datta , M.R. Knox , J.B. Rowe , and J.V. Nolan 1 2 1 1 `Department of Animal Sciences, UNE, Armidale NSW 2351 *CSIRO j Animal Production, Armidale NSW 2350 Extra dietary protein (Coop and Holmes, 1996) or nonprotein nitrogen (Knox and Steel, 1996) helps nematode infected sheep to compensate for the reduced voluntary feed intake and endogenous losses of protein in the gut. The high cost of protein supplements, however, restricts the practical application of this howledge and less expensive ways of obtaining the same benefit were investigated. Four diets were compared: BS (basal; chaffed oaten hay plus 2% urea); SM (basal + 2 g methionine from to provide what primary limiting supplement; `Smartamine'; rurnen-protected Rhone Poulenc Animal Nutrition) is generally considered to be the amino acid as a specific and may indicate a high level of susceptibility and a severe parasite challenge. By week 12 there was an indication that supplementary feeding had a positive effect on survival. It is possible that lack of a liveweight response to Smartamine may be related to gut fill or to the fact that a broader range of amino acids is required. Coop, R.L. & Holmes, P.H. (1996). Nutrition and parasite interaction. International Journalfir Parasitology 26, 95 l-962. Knox, M.R. & Steel, J. W.( 1996). Nutritional enhancement of parasite control in small ruminant production systems in developing countries of south-east Asia and the Pacific. International Journal for Parasitology 26,963-970. CS (basal + 200 g cotton seed meal) to provide a similar amount of methionine as in 2 but with a broader range of amino acids and some additional energy; and BV (basal + 200 g barley premixed with 4 mg of Virginiamycin; Smith, Kline & BeechamAnimal Health) to provide a similar amount of energy as in 3 and extra microbial protein. The virginiamycin was added to overcome problems of grain feeding. These diets were fed to 63 (4 months old; 18.5 kg) Merino lambs. The lambs were kept indoors and accustomed to the basal diet for 1 month. They were drenched with Ivermectin (MSD; 2.5 ml/l0 kg liveweight) and confirmed to be worm&ee 3 weeks later. They were then weighed and allocated at random to treatments. Half of the lambs Tom each diet were uninfected+ontrols and the other half were each infected 3 times per week with both 200 Haemonchus contortus and 1200 Trichostrongylus colubriformis larvae (L,) for 12 weeks. Feed and water were continuously available. Liveweight and faecal worm egg counts were recorded. The results are shown in Figures la, b, c, and d. Weight gain differed (PcO.05) between diets, but faecal egg counts did not differ (P>O.O5). Mortality in infected groups was considerable. There was no response to Smartarnine in infected or uninfected lambs. Contrary to previous studies, none of the diets prevented the onset of clinical disease. This is surprising Recent Advances in Animal Nutrition in Australia 1997 University of New England, Amidale NSW 2351, Australia