Factors affecting the digestibility of varieties of sorghum grain by cattle

Abstract

Experiments were conducted to ascertain the digestibility of varieties of sorghum grain by cattle and to identify factors responsible for these differences. In a preliminary experiment, 27 varieties of sorghum grain were screened by measuring in vitro dry matter disappearance to determine differences in digestibilities of varieties. Eight varieties were selected and grown for feeding in digestion experiments. Varieties for the first digestion experiment were planted in the fall of 1966, in the Lower Rio Grande Valley of Texas. Seven varieties were fed to seven steers in the spring of 1967. Using the total collection method, significant differences in digestibility among varieties were found. The coefficients of digestibility for dry matter, organic matter protein and non-protein organic matter for Tx-09, 7078, Tx-2536, Double Dwarf White Waxy Feterita and Martin were not significantly different. Darset #28 and Shantung Brown Kaoliang had significantly lower coefficients of digestibility for dry matter, organic matter and non-protein organic matter than all varieties except Martin. Generally the same relationships among varieties were observed for the in vivo and in vitro data. The apparent digestibility of protein for Darset and Kaoliang was approximately one-half that of the other varieties. In the second digestion experiment, Shallu was added to the seven varieties studied previously. These varieties were planted on the same land in the spring of 1967. An eighth steer was included with the seven used in the first experiment. Digestibility coefficients were slightly lower than those in the first experiment, but the same relationships existed among varieties. ...