Effects Of Different Proportion Of Alfalfaand Oat Hay On Production Performance Of Dairy Cows

The objective of this study was to explore the rumen digestibility and effects of different proportion of alfalfa and oat hay on milk yield,milk quality,apparent digestibility and serum index in lactating dairy cows.Experiment 1.Effects of different proportion of alfalfa and oat hay on milk yield,milk quality and economic benefits in lactating dairy cowsThere were 60 multiparous Holstein cows which had average body weight 594.7±22.5kg and milk yield 26.34±0.86kg/d in experimental animals.They were randomly divided into 3treatments with 4 replicates each treatment and 5 cows each replicate.The dairy cows were fed with 5.5kg alfalfa hay each day(control group),proportion of alfalfa hay and oat hay was 3:1(treatment A)and 1:1(treatment B),respectively.The experiment period was lasted 8-wk.The results showed that :(1)The dry matter intake(DMI)of the treatment A was significantly enhanced when compared to control group and treatment B,while it was significantly decreased in treatment B compared to control group.Similarly,the cows of the treatment A had the highest milk yield among three treatments,and had a significant difference to the treatment B;However,there was no significant difference between the treatment A and control group.Milk fat percentage of the treatment A was significantly higher than treatment B and control group by 13.61% and12.36% respectively.With the increasing of oat hay in the diets,there was a decreasing tendency in milk protein and somatic cell count,and those of the treatment B were significantly lower than the treatment A and the control group.(2)The economic benefit of the treatment A was increased and that of the treatment B was decreased comparing with the control group.In conclusion,our results suggested that the cows had higher production performance and economic benefit when proportion of alfalfa hay and oat hay was 3:1.Experiment 2.Effects of different proportion of alfalfa and oat hay on apparent digestibility and serum index in lactating dairy cowsOnly 1 was selected randomly per replicate,12 cows were picked to this part from Experiment 1.Total feces collection method was adopted in the metabolism test.Each cow was separated feeding with the bag of feces and urine for 3 days.Collected the feces all the day,mixed and weighed them.Collected 4% of the total feces with five-spot pattern,and 10% tartaric acid which is quarter as weighty as it were added.All the samples were saved under-20℃.DMI and the surplus of diets were measured when the diets were sampling everyday.65℃ air dry oven was used to dry the samples until the weight was constant.10 m L blood samples were drew from the tail veins in the last morning.Then serums were siphoned from the blood samples which had been centrifuged with 3000 g for 10 min.These serums were saved under-20℃ before measured.The results showed that:(1)Compared with control group,the apparent digestibility of NDF and crude protein in the treatment A were significant improved.There were no significant differences for digestibility of EE,Ca and P among three treatments.(2)In serum index,only the concentration of alanine transaminase and aspartate aminotransferase were significantly effected by proportion of oat hay and alfalfa hay,and they had lower concentrations in both the treatments to compare with control group.Experiment 3.Evaluating the associate effect of alfalfa and oat hay with Nylon-bag technique3 Holstein cows with permanent rumen fistula were used as experimental animal.Nylon-bag technique was used to measure the digestibility and effective degradability(ED)of major nutrition composition in diets which were designed in Experiment.1.We Used EDDM and EDCP as the first grade assessment index,meanwhile,EDNDF and EDADF were used as the second grade assessment to evaluate the mechanism of the associate effect.The results showed that:(1)The 72 h rumen digestibility of DM was significantly increased with the increasing of oat hay proportion(P<0.05).The ED of DM in three groups was that: Treatment A> Treatment B>Control group.(2)The 72 h rumen digestibility of CP and EDCP were decreased with the increasing of oat hay proportion.But the RUP was significantly increased in the same conditions.(3)The 72 h rumen digestibility of NDF and EDNDF in three groups had the same sequence: Treatment A> Control group> Treatment B.(4)The72h rumen digestibility of ADF was increased with the increasing of oat hay proportion.The ED of ADF in three groups was that: Treatment A> Control group > Treatment B.