1Martin,Van Houtert.Challenging the retinal for altering VFA ratios in growing ruminates[J]. Feed Mix,1996,4(1):8-12.
2Merchen N R, Firkins J L, Berger L L. Effect of intake and forage level on ruminal turnover rates,bacterial protein synthesis and duodenal amino acid flows in sheep [J]. J. Anim. Sci., 1986,62(1): 216-225.
3Murphy M, M.Akerlind, K.Holtenins. Rumen Fermentation in lactating cows.Selected for fat content fed two forage to concentrate ratio with or silage[J].J.Dairy Sci.,2000,83:756-764.
4Nocek J E, S.Tamminga. Site of digestion of starchin the gastrointestinal tract of dairy cows and its effect on milkyield and composition[J].J.Dairy Sci.,1991,74:3598-3629.
5McAllan A B, Sutton .l D, Beever D E,et al. Rumen fermentation characteristics and duodenal35 nutrient flow in lactating cows receiving two types of grass silage with two levels of concentrates [J]. Anim. Feed. Sci.,Technol.,1994,46:277-291.
6Nsahlai,l.V,D.E.K.Siaw,RO.Osnji. The relationships between gas Production and chemical composition of 23 browses of the genus Sesbania[J].J.Sei.Food Agrie, 1994,65:13-20.
7Batajoo,Shaber K.K.R.D. hnpact of nonfiber carbohydrate on intake, digestion ,and milk production by dairy cows [J].J. Dairy Sci., 1994,77:1580-1588.
8Alhadhrami G,Huber JT. Effect of Alfalfa hay of varying fiber fed at 35 or 50%0f diet on lactation and nutrient utilization by dairy cow[J]. J. Dairy Sci., 1992,75:3091-3099.
5NRC.Nutrient requirements of dairy cattle[ S] ,7th ed.Washington,D.C. :National Research Council,2001.
6MENKE K H, STEINGASS H.Estimation of the en-ergetic feed value obtained from chemical analysis andin vitro gas production using rumen fluid[ J]. AnimalResearch Development, 1988,28(1) :7-55.
7BARKER S B,SUMMERSON W H.The colorimetricdetermination of lactic acid in biological material[ J].Journal of Biological Chemistry,1941,138(2) :535-554.
8MAKKAR H P S, SHARMA O P,DAWRA R K,etal. Simple determination of microbial protein in rumenliquor [ J ]. Journal of Dairy Science,1982,65 ( 11):2170 -2173.
9LOWRY O H,ROSEBROUGH N J,FARR A L,etal.Protein measurement with the Folin phenol reagent[J] .The Journal of Biological Chemistry,1951,193 :265-275.
10SAUVANT D,BAUMONT R,FA VERDIN P. Devel-opment of a mechanistic model of intake and chewingactivities of sheep [ J ]. Journal of Animal Science,1996,74:2785-2802.
