5Alvareza G,Pinos-Rodrigueza J M, Herrerac J G, et al. Effects of exogenous fibrolytic enzymes on ruminal digestibility in steers fed high fiber rations[J]. Lives Science, 2009, 121:150-154.
6Chizzotti M L,Valadares Filho S C, Tedeschi L O, et al. Energy and protein requirements for growth and maintenance of F1 Nel- lore × Red Angus bulls, steers, and heifers[J]. Journal of Animal Science, 2007,85(8):1971 - 1981.
7Koul V,Kumar U,Sareen V K,et al. Mode of action of yeast cul- ture (YEA-SACC 1026) for stimulation of rumen fermentation in buffalo calves[J]. Journal of the Science of Food and Agriculture, 1998,77(3) :407-413.