Effects Of Pendf Levels On Chewing, Rumen Fermentation And Milk Composition Of Dairy Cows

This study was conducted to investigate the effects of dietary peNDF on chewing, rumen fermentation, and milk composition of dairy cattle fed with the same dietary concentrate to forage ratio. Based on a single factor experimental design, 30 healthy dairy cows with two parities, 120 days in milk, and similar body condition were chosen as trial individuals. Diets with different levels of peNDF were obtained by manipulating the mixing duration(10 min, 18 min and 60 min), which was then used to study the eating and ruminating activity, rumen fermentation, and milk content of the cattle. The results showed that, TMR mixing time affected the dietary peNDF8.0 level(P < 0.01); peNDF8.0 at different level influenced the daily intake time(P < 0.05); NDF in the leftover, as well as the rumen pH, decreased with lower levels of peNDF8.0(P < 0.01); peNDF8.0 at different levels had no effect on the milk composition, milk fat, milk protein, lactose, non-fat solids and milk urea nitrogen(P > 0.05). The cellulase activity was inhibited when the amount of pe NDF8.0 was reduced. Nevertheless, the xylanase was not affected by peNDF8.0 level. The total rumen VFA was not significantly changed(P = 0.175); with increasing levels of peNDF8.0, the acetate level and A: P ratio were decreased(P < 0.01), while the propionate was increased(P < 0.01).In order to keep the health status of dairy cow, the recommendations of the peNDF8.0 and mixing duration are 10.56% and 18 min, respectively.