Influence of Sulfur, Molybdenum, Phosphorus and Copper Interrelationships in Cattle upon Cellulose Digestion In Vivo and In Vitro

Abstract

The objective was to determine the effects of mineral interrelationships upon cellulose digestion both in vivo and in vitro by rumen microorganisms. Sulfur increased microbial activity for digesting cellulose. Sixty-five meg. S/ml. of rumen fluid were optimum for rumen microorganisms which would be produced by feeding the dietary requirement of 0.29% S as Na2SO4 for ruminant animals. Phosphorus stimulated microblal activity in vivo and in vitro except for the 0.54% dietary level. S and P gave positive additive effects in vitro, and the depression produced by Copper was lessened by added S. The addition of Cu or molybdenum lessened the depressing effect of the other in the presence of P. With S, Mo, P and Cu additions in vitro, the effects of Mo and the remaining 1st and 2nd order interactions not discussed were not different from the trial mean but were lower than an optimum control. The in vivo bag tchnique gave significant differences among steers and among cellulose sources. Digestibility of cellulose from purified cellulose was highest; cotton linters, intermediate; and sugar cane bagasse, lowest.