Forage to Concentrate Ratio: Effects on Rumen Fermentation in Nanjiang Brown Goats in Vitro

This experiment was conducted to study the effects of different forage to concentrate ratios on rumen fermentation in Nanjiang brown goats in vitro.The rumen fluid was collected from three healthy Nanjiang brown goats [average body weight was(25.48±1.48) kg] fitted with permanent rumen fistulas.A single factor experiment design was adopted,and fermentation substrates with different forage to concentrate ratios were allocated to group 10C(90∶ 10),group 30C(70∶ 30),group 50C(50∶ 50),group 70C(30∶ 70) and group 90C(10∶ 90).The results showed that pH was decreased in the culture medium with the increase of dietary forage to concentrate ratio,and group 10C and group 30C were significantly higher than group 70C and group 90C(P0.05).The concentrations of ammonia nitrogen(NH3-N) and total volatile fatty acids(TVFA) were not affected by dietary forage to concentrate ratio.Microbial protein concentration was gradually increased with the increase of dietary forage to concentrate ratio,and group 90C was significantly higher than the other groups(P0.05).Fermentation rate of organic matter(OM) was significantly increased with the increase of dietary forage to concentrate ratio(P0.05).The acetate/propionate was gradually dropped with the increase of dietary forage to concentrate ratio.In conclusion,under the experimental conditions,high concentrate diet has a positive effect on rumen fermentation in Nanjiang brown goats in vitro.With the increase of the concentrate level,microbial protein content and energy efficiency are increased.