A FERAL GOAT RUMEN FLUID INOCULUM IMPROVES NITROGEN-RETENTION IN SHEEP CONSUMING A MULGA (ACACIA-ANEURA) DIET

Rumen micro-organisms which are resistant to high levels of condensed tannins (CT) may constitute a unique response by feral goats to the nu tritive depressing effects of mulga (Acacia aneura) CT. Transferring t hese micro-organisms to domestic livestock lacking this response may b e beneficial when CT-rich mulga diets are consumed. Three experiments were conducted in which sheep consuming a mulga diet were given a rumi nal inoculation of feral goat rumen fluid (FGRF). Feed intake and nitr ogen (N) retention were significantly greater (P < 0.05) in both sheep and domestic goats following inoculation and in inoculated compared w ith uninoculated sheep. Inoculation also improved N digestibility and reduced the rate of liveweight loss in sheep and domestic goats. These improvements were of similar magnitude to those attributable to the t raditional N, phosphorus and sulfur mineral supplement for mulga fed s heep. FGRF inoculated sheep also grew as much wool as uninoculated she ep receiving a production enhancing mineral supplement. The results fr om these experiments suggest that FGRF is readily transferable to shee p and improves N metabolism in these animals. Using micro-organisms fr om FGRF as an inoculum for sheep consuming a mulga diet has the potent ial to be an alternative to mineral supplements.