| As a methyl donor,choline participates in a variety of biological processes in animals.Many studies have found that choline has a positive effect on improving the negative energy balance of perinatal dairy cows and improving production performance.The purpose of this test is to evaluate the rumen bypass effects of two rumen bypass products and compare their effects on the performance and blood indicators of Holstein cattle during the perinatal period.This subject is divided into two experiments:Experiment 1 uses the Reye’s salt spectrophotometric method to determine the content of choline chloride in two rumen bypass products,and uses the nylon bag method on the rumen bypass effect of the rumen bypass choline on dairy goats and the small intestine The release effect is measured.The results showed that the choline chloride content of product A was 29%,and the choline chloride content of product B was 24.4%.The rumen protection rate of product A is more than 80%after 48h measured by the nylon bag method,product B is more than 50%,and product A has better rumen protection effect than product B.After the rumen protected choline is treated by pepsin and pancreatin,the release rate of product A is more than 90%after 4 hours,and the release rate of product B is more than 70%after 4 hours.From the results,it can be seen that the release effect of A product in the small intestine is better than that of B product.In the second experiment,80 perinatal dairy cows were selected and randomly divided into four groups with 20 cows in each group.The control group(group C)was fed with basal diets,and the two product comparison groups were added with products A or B(groups A and B)equivalent to 12.2g/d/cephaloline according to the recommended addition amount,and another high was set Addition group(P group),use product A to add choline equivalent to 15.2g/d/head to evaluate whether the recommended addition amount is appropriate.The trial period is six weeks,the pre-feeding period is from 21 days to 14 days before delivery,and the trial period is from 14 days before delivery to 21 days after delivery.Milk samples(10 days and 20 days postpartum)and plasma(-14d,-7d,1d,7d,14d and 21d according to calving time)were collected during the experiment.The results showed that:1.Production performanceThe results of adding rumen-protected choline in this experiment showed no significant effecton milk production and milk composition of dairy cows.2.Liver function indicatorsThe blood non-esterified fatty acid content of the test group was significantly lower than that of the control group(P<0.05),and it increased significantly with time.When the blood alanine aminotransferase content is high,it can significantly reduce the alanine aminotransferase content(P<0.05),but it has no significant effect on the aspartate aminotransferase content(P>0.05).The P group treatment reduces the blood alkaline phosphatase content after delivery It can significantly increase the alkaline phosphatase content(P<0.05).On the seventh day after delivery,the albumin level of group C was significantly reduced(P=0.0017).Compared with group C,groups A,B,and P significantly increased the total protein and albumin content in the blood(P<0.05).3.Other blood biochemical indicatorsThe blood triglyceride and β-hydroxybutyric acid content of the test group was significantly lower than that of the control group(P<0.05).When the blood glucose level of the dairy cows decreased on the seventh day after delivery,the blood glucose content of choline-added dairy cows increased significantly(P<0.05)),the blood total cholesterol content of group A and P on the seventh day after delivery was significantly higher than that of group C(P<0.05),and the blood total cholesterol content of group A,B,and C on the 14th day after delivery was significantly lower than that of group P(P<0.05)),the blood high-density lipoprotein cholesterol content of the A,B,and P groups was significantly higher than that of the C group on the 7th day after delivery(P<0.05),and the low-density lipoprotein cholesterol content of the A and P groups was significantly higher on the 7th postpartum day In group C(P<0.05),the content of low-density lipoprotein cholesterol in group P on the 14th day after delivery was significantly higher than that in groups A,B,and C(P<0.05).The blood indicators indicate that the addition of rumen protected choline can have a positive effect on the fat metabolism process of dairy cows and improve the synthetic function of the liver.Main conclusion1.The rumen bypass effect and small intestine release effect of A product is better than that of B product.2.Adding 42g/day/head of product A to the diet can be better than adding 50g/day/head of product B on some blood indicators,and adding 52.5g/day/head of product A can be better on some blood indicators.The effect of adding 42g/day/head A product.3.Adding rumen-protected choline to the perinatal dairy cow’s diet can significantly improve the postpartum stress of dairy cows and help alleviate the liver function damage and negative energy balance of dairy cows. |
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