Effects of cottonseed meal and cereal grain supplements on intake and utilization of alkali treated wheat straw.

Abstract

Animal Production in Australia EFFECTS OF COTTON-SEED MEAL AND CEREAL GRAIN SUPPLEMENTS ON INTAKE AND UTILIZATION OF ALKALI-TREATED WHEAT STRAW J.C. SPRAGG*, R.C. KELLAWAY* and T . J. KEMPTON** Growth rate of cattle eating NaOH-treated wheat straw was increased by ing a supplement of cotton-seed meal, when intake of straw was unaffected by supplement (Sriskandarajah et al. 1981). This paper reports on a subsequent periment in which comparative growth responses to supplements of cotton-seed and cereal grains were examined. feedthe exmeal Wheat straw was sprayed with a NaOH solution (40 g NaOH in 113 g H20/kg) followed by a mineral solution supplying (g/kg) 79 H20, 15 N, 1 S and (mg/kg) 4 Cu, 0.1 Co and sprinkled with dicalcium phosphate supplying (g/kg) 2.0 P and 2.6 Ca. The treated straw was supplemented with 800 g/day of cotton-seed meal (CSM), cracked barley (CB), extruded barley (EB), ammonia-treated whole barley (NB) or whole barley (WB) and fed to 45 Friesian heifers (250 kg live weight). TABLE 1 Dry matter intakes (DMI) of treated straw, digestible organic matter in dry matter (DOMD), intake of digestible organic matter (DOMI) and live-weight gain (LWG) of Friesian heifers fed supplements with a basal diet of NaOH-treated straw The mean intake of treated straw on CSM, EB and CB treatments was higher than the mean intake on WB and NB treatments (P < 0.05). Similarly, DOMI and LWG were higher on treatments CSM, EB and CB than on treatments WB and NB (P < 0.05). High DOMI values were attributable to high DM1 and DOMD values. Total DM1 was unusually high (125-134 g WC-75) for dry cattle eating such a poor quality diet. Lower DOMD on WB than CB conforms with known differences in digestibility of whole and cracked grains in cattle. Under conditions of this experiment, ammoniatreatment of whole grain had a negligible effect on its digestibility. Responses in DOMI and LWG on CB and EB were not significantly different from those on CSM, although there was a trend which indicated marginal superiority of CSM. Oldham et al. (1979) reported that when urea + barley, comprising 34% of a forage/concentrate diet, was replaced by fish meal, there was a synergistic effect on digestibility. In the present experiment, where supplements comprised 8% of the diet, the marginal effect of CSM on DOMD may have had a synergistic component. OLDHAM, J-D., BROSTER, W-H., NAPPER, D-J., and SMITH, T. (1979). Proc. Nutr. Soc. 38: 128A. SRISdARAJAH, N., KELLAWAY, RX., and KEMPTON, T-J. (1981). Br. J. Nutr. (In Press.) * Department of Animal Husbandry, University of Sydney, Camden, N.S.W. 2570. ** Department of Biochemistry and Nutrition, University of New England, Armidale, N.S.W. 2351. 679