Study On Application Of Double-Low Rapeseed Meal Replacing Cottonseed Meal And Soybean Meal In High Producing Dairy Cows

This experiment was conducted to study the effects of double low rapeseed meal (canola meal) replacing cottonseed meal and soybean meal on milk performance, nutrient apparent digestability, biochemical parameters in sereum and immune functions of high producing dairy cows, in order to provide theoretical foundation and technical support for the application of the double low rapeseed meal in diet of high producing dairy cows. Three hundred and thirty Holstein dairy cows similar in health condition, weight, parityies, lactation periods and milk production were divided into three groups with110dairy cows in each group in a single factor random design. Pre-trial period lasted15d and the experimental period lasted60d.The control group was fed with the farm’s feedstuff containing the soybean meal and the cottonseed meal, the first group substituted canola meal for50%soybean meal and cottonseed meal, and the second group substituted canola meal for50%soybean and cottonseed meal during the prior period of the trail, and substituted canola meal for50%soybean and cottonseed meal during the later period. The results showed as followed under the present experimental conditions:1. Feeding1.2kg or2.4kg canola meal per day for each cow to replace50%or100%cottonseed meal and soybean meal resulted in increased daily milk production (1.57kg or1.45kg respectively), and especially in the prior period, increased daily milk production reached above2kg (P<0.05).The milk protein production was significantly increased, but all of the milk composition and milking efficiency were not significantly affected.2. High producing dairy cows fed with1.2kg or2.4kg Canola meal everyday replacing50%or100%cottonseed meal and soybean meal could significantly increase the DMI and decreased the MUN and BUN contents, and the average DMI was increased above1kg (P<0.01) 3. The effects of canola meal on contents of the GH、IGF-1、COR、 PRL and INS in serum of high yield dairy cows were not significant (P>0.05), and the effects on NEFA and SG contents were also not obvious (P>0.05)4. The effects of canola meal on the apparent digestibility of nutrients in the feedstuff wer. not obvious (P>0.05). But the digestibility of the CP, P, ADF and NDF had a tendency to be increased compared to the control.5. Feeding high producing dairy cows canalo meal had no significant effects on SCC and immune functions of high yield dairy cows (P>0.05)6. It was practicable that high producing dairy cows were fed1.2kg/d or2.4kg/d canola meal to replace50%or100%cottonseed meal and soybean meal, which could increase economic benefits.