Effects Of Adding Niacin To Diet And Dietary Concentrates To Roughage Ratio On Milk Performance, Rumen Fermentation And Rumen Cellulolytic Bacterium In Dairy Buffalo

Based on the biological advantages of high temperature and coarse food resistances of buffalo, this experiment was conducted to investigated the effects of adding niacin to diet and dietary concentrates to roughage ratio on milk performance, rumen fermentation and rumen cellulolytic bacterium in dairy buffalo under the condition of high temperature and high humidity in summer,and high roughage in diet.Experiment one:36healthy crossbred dairy buffalo (indigenous X Nili-Ravi X Murrah)which have a daily milk yield of over5kg and have milked over30days were collected to divided into randomly one control group and three treatment groups in accordance with the similar principle of milk yield and lactation, each groups have nine buffalo. The control group was fed with basis diet, the treatment groups were fed with experimental diet which added niacin of4g/d,8g/d,12g/d, respectively. This experiment studied effect of dietary niacin on milk yield, milk components, dry matter intake(DMI), dietary nutrient digestibility, rumen fermentation parameter and the amount of the main cellulolytic bacterium in rumen. The result shows that the rectal temperature and respiratory rate of the dairy buffalo is normal on the condition of summer high temperature. DMI increased along with the dosage of niacin. That of the treatment group of adding niacin12g/d is significantly increased by4.82%when compared with the control group (P<0.05). Adding niacin can improve the apparent digestibility of energe and nitrogen of the dairy buffalo, and adding niacin8g/d can significantly increases the digestibility of nitrogen by6.36(P<0.05), but the differences of the apparent digestibility of neutral and acid detergent fibers are not significant (P>0.05). Compared with the control group, adding niacin8g/d and12g/d can increase the4%standard milk yield by11.51%and8.09%(P<0.05), adding niacin4g/d,8g/d and12g/d can significantly increase the protein rates of milk by9.31%,9.31%and4.41%(P<0.05). Adding niacin in daily diet has no influence on serum biochemical parameters and blood immunity parameters. The concentration of ammonium nitrogen and lactate in12g/d group is higher than that of4g/d group (P<0.05). Adding niacin in daily diet has no significant influence on the amount of the main rumen cellulolytic bacterium (P>0.05).Experiment two:15healthy crossbred buffalo replacementheifers were collected to divided randomly into3groups in accordance with no significant different in live body weight and age, and was fed diet with concentrate-to-roughage ratio of0:10,3.5:6.5,5:5respectively to study the effect of dietary different concentrates to roughage ratio on rumen fermentation parameter, the amount of the main rumen cellulolytic bacterium and the serum biochemical index. The result shows that with the increase of the dietary concentrate level, the amount of protozoon in rumen gradually increased, and that of5:5group significantly increased by228.57%and43.75%when compared with that of0:10group and3.5:6.5group (P<0.05). The concentration of liquid ammonia also increased by38.12%and4.30%(P<0.05). The amount of fibrobacter succinogenes and butyrivibrio fibrisolvens in rumen reduced as the dietary concentrate level raised, the amount of fibrobacter succinogenes of5:5group is reduced by70.72%when compared with that of0:10group (P<0.05), and the amount of butyrivibrio fibrisolvens is reduced by28.32%(P<0.05). The amount of ruminobacter albus and ruminococcus flavefaciens in all group was similar (P>0.05). The concentrations of urea nitrogen, total cholesteral and HDL in serum increased along with the dietary concentrate level, which increased by66.23%(P<0.05) and86.75%(P<0.05),37.40%(P<0.05) and41.46%(P<0.05),43.21%(P>0.05) and50.62%(P<0.05) respectively when comparing3.5:6.5group and5:5group with0:10group.The conclusions from the two tests are as follow:(1) Under the condition of summer high temperature, adding niacin in daily diet has no significant influence on the rectal temperature and respiratory rate, but can improve dairy buffalos’ production performance and rumen fermentation, improve the apparent digestibility of dietary energe and nitrogen, and the optimum adding dose was8g/d.(2) Dietary concentrates to roughage ration has different degree of influence on rumen fermentation parameter, the amount of the main rumen cellulolytic bacteria and serum biochemical parameters and the amount of rumen celluloytic bacterium in the group of0:10is significant higher than the that of group of5:5.