日粮中添加过瘤胃胆碱对围产期奶牛生产性能、代谢性能的影响研究OA

The objective of this study was to examine the impact of rumen-free choline(RPC)supplementation on the performance and metabolic profile of dairy cows during the perinatal period.A total of 100 healthy cows with an average expected date of delivery(21±3)days were selected and randomly divided into 2 groups of 50 cows each,with 1～3 parity.The control group was fed a basal diet,while the experimental group was fed a basal diet supplemented with 30 g/(head·d)ruminal choline(RPC,with a choline content of≥57%,ruminal clearance rate of≥90%,and small intestine release rate of≥90%).The prefeeding period was 7 days,followed by a formal period of 42 days(antepartum:21 days;postpartum:21 days).During the experimental period,the cows were permitted to consume adlibitum,drink and move freely.The results demonstrated that in comparison to the control group,the experimental group exhibited increased prenatal feed intake,and elevated weight of newborn calves(P>0.05),and augmented milk yield increased by 1.2 kg/d,in the second week of the experiment,the milk yield of the experimental group was 5.9%higher than that of the control group(P<0.05);No significant differences were observed in milk protein,milk fat percentage and lactose.The blood concentrations of non-esterylated fatty acid(NEFA)and β-hydroxybutyric acid(BHBA)of the experiment group in the postpartum 7 days were decreased by 21.2%and 32.3%,respectively compard with the control group(P<0.05).The blood levels of high-density lipoprotein(HDL)and low-density lipoprotein(LDL)in the experimental group were higher than those in the control group 7 days after delivery by 27.4%and 44.4%,respectively(P<0.05).Among the immune indexes of newborn calves,the blood IgG concentration in the experimental group was increased by 47.1%compared with the control group(P<0.05).It was concluded that the addition of 30 g/(head·d)RPC to the diet of perinatal dairy cows can help to reduce ketosis,reduce fat mobilisation,and improve the health of perinatal dairy cows and the weight and immunity of newborn calves.