Abstract:
INTAKE AND DIGESTIBILITY OF WHEAT STRAW BY SHEEP AS AFFECTED BY UREA AND/OR LUCERNE INTAKE * I .B.Sudana and R.A. Leng* There is an optimal level of rumen ammonia in the rumen of s h e e p c)r cattle on fibrous based diet necessary for maximum microbial growth and fermentation activity. However, suggested levels have varied f`rom 50mg/l (Satter and Slyter 1974) to as high x 340mg/l (Kellaway and Leibholz 1980) hut more recently ZUOmg/l NH3N/1 has been suggesLed to optimize intake (Boniface et a1.1986; Perdok and Leng 1988). It is now recognize a small quantity of high quality forage can affect digestibility of a basal poor quality fibrous diet; thus there maybe interaction txtween;forage type and ammonia levels (Silva and Orskov 1988). The results of the experiment are shown in the Table. Table. Humen ammonia levels, straw intake, straw organic matter digestibility (POM) and wool growth\ of sheep given a basal diet of wheat straw (BD),or +15y urea (BDtlSlJ),or + 309 urea (BD+SOU),or t 150~ lucerne (BDtL),or t 15g urea+ 15Og lucerne(BDI-1SUtL) ort30g ureatl50g lucerne(BDt30UtL). The results of the experiment tend to suggest that factors other than rumen ammonia alone are involved in the responses in improving straw intake and its digestion.The protein and other nutrients in lucerne and its highly fermentable nature appeared to have improved the rumen environment and increased microbial growth (as indicated by wool growth), improved digestibility and enhanced straw intake. BONIFACE,A.N., MURAY,R.M.and HOGAN,J.P.(1986).Aust.Soc.Ani.m. Prod.l6:151. KELLAFRy.and LEIBHOLZ,J.(1980).Aust.Soc.Ainm.Prod.l4:61. PERDOK,H.and LENG,R.A.(1988).Proc.OECD/UNE Int.Sem.(inTress). SATTEK,L.D.and SLYTER,L.L.(1974).Br.J.Nutr.32:199. SILVA,A.T.and ORSKUV,E.R.(1988).AnimFeed Sz.Technol.19:277. * Department-Of Biochemistry,Microbiology and Nutrition, University Of New England, Armidale, NSW 2351. 31A