Abstract:
Proc. Aust. Soc. Anim. Prod. I996 Vol. 21 FEEDING CANOLA MEAL TO REPRODUCING OR DRY EWES D.G. MASTERS and G. MATA CSIRO Division of Animal Production, Private Bag, PO, Wembley, WA. 6014. Wool growth is depressed in pregnancy and lactation resulting in lower fleece weights and possibly reduced staple strength. Feeding protein that escapes degradation in the rumen in late pregnancy and early lactation increases wool growth (Masters et al. 1996), but most protein supplements are either highly degraded in the rumen (eg lupinseed) or expensive (eg fishmeal, meatmeal). Canola meal may provide a practical option as it is partially protected from degradation in the rumen and is cheaper than other sources of partially protected proteins. This experiment aimed to measure wool production and lamb weights and growth when the major source of protein in the diet was either lupinseed or canola meal. Following synchronised mating, 30 ewes carrying a single fetus and 30 dry ewes, all of similar conceptusfree liveweight, were housed in single pens and allocated to 1 of 4 groups (2 of 15 reproducing ewes and 2 of 15 dry ewes). The groups were fed 1 of 2 diets from day 127 of pregnancy to day 2 1 of lactation (days 4284 for the dry ewes). The lupinseed diet (L) consisted of (in g/kg DM) oaten hay (705), lupinseed (250), urea (20), gypsum (5) and Siromin@ (20) and the canola meal diet (CM) contained oaten hay (637), canola meal (240), corn starch (75), urea (20), calcium carbonate (8) and Siromin@ (20). The crude protein (CP), by analysis, was 165 and 184 g/kg DM for L and CM diets. The diets were formulated after analysis of individual components and the CP should have been the same. It is likely that the higher CP content of the CM diet was due to a sampling error with the finer canola meal settling out in the feed sample. The canola meal was produced by extraction of oil from the canola seed, using an expeller process. All sheep had a restricted access to feed estimated to maintain conceptus-free liveweight. Wool was clipped from midside patches (100 cm2) every 3 weeks, washed in detergent and X2 solvent and clean wool growth calculated. Fibre diameter was measured using an Optical Fibre Diameter Analyser. Ewes were shorn 75 days after the end of the experiment and midside samples used for measurement of staple strength (using Agritest). Lambs were weighed at birth and 21 days after birth. Table 1. Effect of reproduction (R) and diet (D) on wool growth, fibre diameter and staple strength These results indicate that wool growth of ewes fed to maintain liveweight in late pregnancy and early lactation is restricted by a lack of protein available for absorption in the intestine. The trend (interaction was not significant) towards a higher response to canola meal in the reproducing than in the dry ewes is consistent with a higher protein requirement in reproducing sheep. Increases in wool growth from feeding canola meal were similar to those observed from other partially protected proteins (Masters et al. 1996). This research was partially funded by Australian woolgrowers through IWS. MASTERS, D.G., STEWART, C.A., MATA, G. and ADAMS, N.R. (1996). Anim. Sci. 62: (in press). 368