Effects of forage to concentrate ration on rumen fluids and acetate,propionate and butyrate in serum of lactating dairy cows

【Objective】 The research studied dynamic changes of rumen pH and VFA,serum acetate,butyrate and butyric acid concentrations.【Method】 Five healthy cows during the dry period were used to study the effects of forage to concentrate ration on dynamic change of rumen pH and VFA in rumen and serum.Cows were fed continuously in nine experiment periods with 30 d in each period except the last one with only 3 d.Dietary forage to concentrate ration were 30∶70,35∶65,40∶60,45∶55,50∶50,55∶45,60∶40,70∶30,100∶0 concentration respectively.【Result】 Rumen pH was down gradually with the increase of forage to concentrate ration and tended to be the lowest in 100:0 concentration(P0.05).Serum acetate were significantly lower(P0.05) in 50∶50 compared with 30∶70,35∶65 and 100∶0 concentration.Serum propionate and butyrate were not significantly different(P0.05).No relationship was observed between rumen acetate,butyrate and acetate,butyrate in serum(P0.05),while the relationships between rumen propionate and serum propionate reached extremely significant(P0.01).【Conclusion】 Different forages to concentrate rations have notable effects on rumen pH,VFA and propionate in serum,the cow obtained tolerance and established stable rumen ecosystem with the increase of forage to concentrate ration.