title: Effects of Forage:Concentrate Ratio on Growth Performance, Ruminal Fermentation and Blood Metabolites in Housing-feeding Yaks.
abstract: The objective of this study was to determine the effect of forage: concentrate ratio (F:C) on growth performance, ruminal fermentation and blood metabolites of housing-feeding yaks. Thirty-two Maiwa male yaks (initial body weight = 207.99±3.31 kg) were randomly assigned to four dietary treatments (8 yaks per treatment). Experimental diets were: A, B, C, D which contained 70:30, 60:40, 50:50 and 40:60 F:C ratios, respectively. Dry matter intake and average daily gain in yaks fed the C and D diets were greater (p<0.05) than yaks fed the A and B diets. No differences were found in ruminal NH3-N, total volatile fatty acids, acetate, butyrate, valerate, and isovalerate concentrations. The propionate concentration was increased (p<0.05) in the C and D groups compared with the A and B diets. In contrast, the acetate to propionate ratio was decreased and was lowest (p<0.05) in the C group relative to the A and B diets, but was similar with the D group. For blood metabolites, no differences were found in serum concentrations of urea-N, albumin, triglyceride, cholesterol, low density lipoprotein, alanine aminotransferase, and aspartate aminotransferase (p>0.05) among treatments. Treatment C had a higher concentration of total protein and high density lipoprotein (p<0.05) than A and B groups. In addition, there was a trend that the globulin concentration of A group was lower than other treatments (p = 0.079). Results from this study suggest that increasing the level of concentrate from 30% to 50% exerted a positive effect on growth performance, rumen fermentation and blood metabolites in yaks.
authors.forename: G J
authors.initials: GJ
authors.lastname: Chen
authors.forename: S D
authors.initials: SD
authors.lastname: Song
authors.forename: B X
authors.initials: BX
authors.lastname: Wang
authors.forename: Z F
authors.initials: ZF
authors.lastname: Zhang
authors.forename: Z L
authors.initials: ZL
authors.lastname: Peng
authors.forename: C H
authors.initials: CH
authors.lastname: Guo
authors.forename: J C
authors.initials: JC
authors.lastname: Zhong
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
keywords: Blood Metabolites; Forage:Concentrate Ratio; Growth Performance; Ruminal Fermentation; Yak