Study The Changes On Rumen Fermentation And Blood Index In Dairy Cows Under L.ow Milk Fat Diet Model

4 Chinese Holstein were selected cows with good body condition,similar body weight and the same parity to study the effects of different dietary-induced milk fat decline patterns on milk composition,rumen metabolism,antioxidant and immunity of dairy cows.At the first phases basal diet was feed in dairy cows of the control group,at the second phase 1.5 kg of finely pulverized corn was added to the basal diet per day.andatthelastperiodl.5 kg of finely pulverized corn and 150 ml of flax oil was added per day to the basal diet.Results are as follows:The addition of finely pulverized corn significantly reduced the milk fat of dairy cows(P<0.01),and the changes of milk protein and lactose content were not significant(P>0.05).The addition of finely pulverized corn+flax oil significantly reduced milk fat(P<0.01),milk protein was not significantly changed(P>0.05),and lactose content increased significantly(P<0.05).Adding finely pulverized corn,the concentration of ammonia nitrogen(NH3-N)and butyric acid in the rumen increased,but the change was not significant(P>0.05);the acetic acid decreased,the difference was significant(P<0.05),and the propionic acid increased.The difference was extremely significant(P<0.01);the microbial protein(MCP)was significantly decreased(P<0.01).Adding finely pulverized corn+flax oil combination,NH3-N concentration decreased,but not significant(P>0.05);acetic acid and propionic acid increased significantly(P<0.01),butyric acid increased significantly(P<0.05);MCP changes Not significant(P>0.05).After adding finely pulverized corn,the ?-hydroxybutyric acid(BHBA)in the blood of the cow was significantly decreased(P<0.05),and the insulin(INS),blood glucose(GLU)and triglyceride(TG)were significantly increased(P<0.01),the non-esterified fatty acid(NEFA)was significantly decreased(P<0.01),and the urea nitrogen(BUN)was significantly increased(P<0.05).However,the difference between BHBA and NEFA in the finely pulverized corn+flax oil combination was not significant.(P>0.05),INS,GLU and TG were significantly increased(P<0.01),and BUN was significantly increased(P<0.05).Albumin(ALB),interleukin-6(IL-6),tumor necrosis factor alpha(TNF-?),immunoglobulin G(IgG),immunoglobulin M(IgM)in the blood of dairy cows after finely pulverized corn All of them increased,while immunoglobulin A(IgA)decreased,the difference was not significant(P>0.05).The addition of ALB,IL-6,TNF-?,IgG and IgM in finely pulverized corn+flax oil combination There was an increase,but the difference was not significant(P>0.05),while IgA was significantly decreased(P<0.01).The total antioxidant energy(T-AOC)activity in the blood of dairy cows was significantly increased after adding finely pulverized corn(P<0.05),and the difference of superoxide dismutase(SOD)activity and malondialdehyde(MDA)content was not significant(P<0.05);After adding finely pulverized corn+flax oil combination,the difference of T-AOC and SOD activity was not significant(P>0.05);MDA content was significantly decreased(P<0.01).The results showed that the combination of finely pulverized corn and finely pulverized corn+flax oil reduced the milk fat of dairy cows,and the change of milk protein was not significant.The content of lactose added to fine pulverized corn+flax oil increased significantly.The addition of finely pulverized corn and finely pulverized corn+flax oil did not significantly change the concentration of rumen NH3-N,and the concentration of propionic acid increased significantly.When finely pulverized corn was added,acetic acid decreased significantly and MCP content decreased significantly.Adding finely pulverized corn and finely pulverized corn+flax oil combination all significantly increased INS.GLU and TG,and BUN increased significantly,which inhibited the immunity of dairy cows and promoted the anti-oxidation level.