| The present study was conducted to investigate the effects of different levels of ruminant-protected betaine on lactation production, blood components and rumen fermentation in early lactation cows by rumen fermentation in vitro and feeding experiment, to provide reference for betaine being used on dairy cow. Experiment one:The present study was conducted to investigate the effect of betaine on rumen fermentation in vitro. The test is divided into 3 treatments. The betaine were added at levels of 0,1.2mg and 3.6mg in 45ml rumen fluid, with 300 mg mixture common diet in rumen fluid. Gas production (GP) was recorded respectively at 3,6,12,18 and 24h incubation in vitro. The incubation was stopped at 6h,12h and 24h and then the inoculants were determined for rumen fermentation parameters.The result showed that The GP in treatments was higher than control all the time and treatmentⅡwas significant(P<0.05). The pH of ruminal fluid was slightly lower, but all values were in the normal range(pH between 6-7).The pH of ruminal fluid at 6h in treatmentⅡwas lower than that of control (P<0.05), and the rest were not significant(P>0.05). That DMD and the content of MCP in treatments were higher than the control (P<0.05), and were higher than the control at 6h(P<0.05). The content of ammonia-N in treatmentⅠat 12h was lower than the control (P<0.05), and in treatmentⅡat 12h(P<0.01) and 24h(P<0.05).The lactic acid in treatment were not significant(P>0.05) all the time. All VFAs increased obviously as rumen fermentation continue. The content of butanoic acids at 12h in treatmentⅡwas higer than the control(P<0.05), and ohers were not significant(P>0.05). It is suggested that 1.2mg and 3.6mg betaine could decrease pH of rumen fluid,and improve the content of gas production, ammonia-N, DMD, MCP and VFA,with dose dependent.Experiment two:Thirty dairy cows were divided into three groups according to the same of age, parity, number of lactations and milk yield.Each group has ten cows, and live in the same conditions. Dairy cows were fed a common TMR.No betaine was included in diet of control.TreatmentⅠandⅡwere respectively added to 6g/d andl2g/d rumrn-protected betaine, with pre-feeding 7 days and 83 days of being fed. The results showed that 6g/d and 12g/d rumrn-protected betaine can respectively increase milk yiled 0.62kg/d and 0.36kg/d, and the difference were not significant(P>0.05). Compared with the control, milk fat, milk protein, non-fat solids in treaments were increasing, but the difference was not significant (P>0.05).Milk lactose in treatments were significantly higher(P<0.01).Milk ketone and total solids content of treatmentⅠwere significantly higher than that of control(P<0.01), with the rest not significant (P>0.05).The SCC of treatments were lower than that of control (P<0.01and P<0.05respectively).The MUN of treatmentⅡwas significantly lower than that of control(P<0.01),and that of treatmentⅠwas not significant (P>0.05). Rectal temperature in the treaments were lower than that of control (0.15℃and 0.06℃respectively), but no significant difference (P>0.05). The results indicated that 6g/d rumen-protected betaine is better to improve milk yield of early lactation cows and reduce rectal temperature.12g/d rumen-protected betaine has a better effect on milk composition. Experiment three:Thirty dairy cows were divided into three groups according to the same of age, parity, number of lactations and milk yield.Each group has ten cows, and live in the same conditions. Dairy cows were fed a common TMR.No betaine was included in diet of control.TreatmentⅠandⅡwere respectively added to 6g/d andl2g/d rumrn-protected betaine, with pre-feeding 7 days and 83 days of being fed. The results showed that During the experiment,the TC, TG, HDL-C and LDL-C were lower than that of control,with the TC and HDL-C at 10 week in treatmentⅡsignificantly lower than that of control(P<0.01) and the TG and LDL-C lower than that of control(P<0.05). Plasma total protein, albumin, globulin tended to increase, albumin and globulin in treatment I were higher than the control(P<0.05) at first week, other differences were not significant (P> 0.05).During the experiment, the MDA of control and treatment increased,the SOD and GSH-PX were lower. The GSH-PX in treatmentⅠwas significantly lower than that of control at tenth week (P<0.05), and the SOD was significantly lower than control(P<0.01).The MDA, SOD and GSH-PX content in treatmentⅡwere not significant than that of control at 10 week (P> 0.05). The results indicated that 12g/d rumen-protected betaine has a good effect on the promotion of fat metabolism and increasing immunity.6g/d rumen-protected betaine is better for cows aginst oxidation. |
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