Abstract:
Animal Production in Australia EFFECTS OF TREATING OAT STRAW WITH SODIUM HYDROXIDE ON BACTERIAL PROTEIN SYNTHESIS AND SITES OF ORGANIC MATTER DIGESTION IN CATTLE R.G. REDMAN*, R.C. KELLAWAY*, and JANE LEIBHOLZ* Substantial increases in the intake of cereal straws following NaOH treatment, were effected by increases in the digestion rates of cell walls in the rumen, and in the clearance rates of undigested cell walls from the rumen (Thiago et al. 1979). Associative effects of NaOH treatment of oat straw on bacterial protein synthesis and sites of organic matter digestion were measured in four steers fitted with rumen, abomasal and ileal cannulas. Each of the steers was fed untreated and NaOH-treated (40 g NaOH/kg) oat straw ad lib. in two successive periods of 17 days duration. Both straws were also sprayed with urea (supplying 11.5 g N/kg) and mineral solutions as described by Kellaway et al. (1978). Bacterial nitrogen (N) in abomasal digesta was estimated using 2,6-diaminopimelic acid as a marker. Intakes and flows of organic matter (OM) and nitrogen (N), and rumen TABLE 1 concentrations of volatile fatty acids (VFA) and NH3 in steers eating oat straw (U) and NaOH-treated oat straw (A) Intakes of diet A were 39% higher than intakes proportions of OM intake digested in the stomach were digestibilities in the whole tract were 0.55 and 0.66 ively (P<O.O5), the difference being due to a higher being digested post-ruminally on diet A. of diet U similar. on diets U proportion (P<O.Ol), although Organic matter and A respectof OM intake U (P<O.Ol). excess of There was some diet A than on Rumen VFA concentrations were higher on diet A than on diet Rumen NH3 concentrations were similar on the two diets and well in levels considered to be optimal for bacterial protein synthesis. evidence that synthesis of bacterial protein was more efficient on diet U, although this difference was not significant @>0.05). KELLAWAY, R.C., CROFTS, F-C., THIAGO, L.R.L., REDMAN, R.G., LEIBHOLZ, J.M.L. and GRAHAM, C-A. (1978). Anim. Feed Sci. Technol. 3: 201. THIAGO, L-R-L., KELLAWAY, R-C. and LEIBHOLZ, J. (1979): Ann. Rech. Vet. 12: 329. *Departmen t of Animal Husbandry, University of Sydney, Camden, N.S.W. 482 2570.
