3Berthiaume R, Lapierre H, Stevenson M. Comparison of the in situ and in vivo intestinal disappearance of ruminally protected methionine[J]. J Anim Sci, 2000, 83: 2049-2056.
4De Boer G, MuPRhy J J, Kennelly J J. Mobile nylon bag for estimating intestinal availability of rumen undegradable protein[J]. J Dairy Sci, 1987, 70: 977-982.
5Overton T, Lacount D, Cicela T, et al.Evaluation of a ruminally protected methionine product for lactating dairy cows[J]. J Dairy Sci, 1996, 79: 631-638.
6National Research Council.Nutrient requirements of dairy cattle[S].Washington, D C: National Academy Press, 1989.
7Niimrick K E,et al. [J]. J Nutr,1970b,100:1301.
8Chalupa W. [J]. Anim Sci,1976,43:829-834.
9Onodera R. [J]. Amino Acids, 1993, (5):217-232.
10Patterson J A,Kung L Jr. [J]. J Dairy Sci,1988,71:3292-3301.