Persian clover and maize silage. III. Rumen fermentation and balance of nutrients when clover and silage are fed to lactating dairy cows

Six rumen fistulated dairy cows, at various stages of lactation, were housed in metabolism stalls on a total of nine occasions in three experiments in which various combinations of Persian clover (Trifolium resupinatum) and maize (Zea mays) silage were offered. These experiments considered some aspects of digestion of Persian clover and Persian clover/maize silage diets in order to understand the good milk yield responses attributed to maize silage measured in previous research. Rumen ammonia concentrations and nylon bag degradation rates suggested that the cows made better use of one or both feeds when Persian clover and maize silage were offered together than they did when Persian clover was offered alone. While Persian clover and maize silage appeared to be a substantially inferior diet in terms of apparent in vivo digestibility coefficients and availability of nutrients when compared with Persian clover offered alone, milk yields were unaffected. In addition, no matter how much maize silage was offered, milk fat content remained constant. These results were attributed to an improved balance of absorbed nutrients.