| Recently,husbandry industries play an important role in the globe warming.China is a huge animal industry in the world,and with the rapid of development of animal industry,results in a serious waste of energy,and released a lot of greenhouse gas.So,it is not investable for animal husbandry to conserved energy and reduction emission.It is common for dairy cows to develop subacute ruminal acidosis,which decreased milk yields and feed utilization.It made a serious economic loss for livestock industry.Therefore,we study on the production performance,reproductive performance,feed utilization and greenhouse gas emission of dairy cows with subacute ruminal acidosis in an intensive dairy farm in Heilongjiang province,in order to lay the foundation for the measures of energy saving and emission reduction.In test one,the aim of this study was to investigate the effects of subacute ruminal acidosis on the performance,reproduction performance and secondary other disease in a large intensive dairy farm of Heilongjiang province.According “AFI-milk” software,50 health cows and 50 subacute ruminal acidosis cows within 30 day after calving were selected.Basic information of dairy cows,production,reproduction performance and clinical symptoms were recorded,and conduct an epidemiological survey of dairy cows.The results showed that the average daily milk production in subacute ruminal acidosis(SARA)group was significantly lower than that in control(CON)group(P < 0.01).the days of calving to first estrus,calving interval and days of first AI in SARA group were significantly longer than that in CON group(P < 0.01).There was a significantly positive correlation between the laminitis and subacute ruminal acidosis(P < 0.05).In test two,the aim of this study was to investigate the characterize of the performance,feed digestion and fecal discharge of dairy cows.Selected 12 cows in an intensive dairy farm,and divided them into SARA group(n=6)and CON group(n=6)according the p H and clinical symptoms.Collected the samples of serum,urine,milk and fecal and analysis the component of them.The results showed that the concentration of NEFA in SARA group was significantly higher than that in CON group(P < 0.01),the concentration of BHBA in SARA group was significantly higher than that in CON group(P < 0.05),the lactate levels of serum in SARA group was significantly higher than that in CON group(P < 0.01).In addition,the concentrations of total protein and albumin were significantly lower than that in CON group(P < 0.01).AST and CK contents in SARA group were significantly higher than that in CON group(P < 0.05).In the milk,the milk fat,milk protein and non-fat milk solids contents in the SARA group were significantly lower than that in CON group(P < 0.01).In the urine,the Mg2+content in the SARA group was significantly lower than that in the CON group(P < 0.01).The emission of N from fecal in SARA group significantly higher than that in the CON group(P < 0.05).Chemical oxygen demand of fecal in SARA group were significantly higher than that in the CON group(P < 0.01).In test three,the purpose of this study was to study the emission of greenhouse gas and NH3 in the mixture of fecal and urine,and estimate the emission of greenhouse gas in an intestine dairy farm.Selected 12 cows and divided them into SARA group(n=6)and CON group(n=6)according the p H and clinical symptoms,the test period was four days.In the experiment period,cows were isolated breed and collected the samples of feces and urine.The greenhouse gas emissions from the mixture of fecal and urine of dairy cows were collected by the simple dynamic box method for 117 h and analyzed them by ANOVA1412.The results showed that the CH4 and CO2 emission in SARA group were higher than CON group,but there was no significantly difference.The emission of NH3 in SARA group was lower than that in the CON group.Estimate the emission of greenhouse gas between SARA group and CON group by using the life assessment cycle method,the results showed that the emission of CH4 from intestine fermentation between two groups was similar,while the CH4 and N emissions from fecal in SARA group was higher 5.56 kg/d and 0.01 kg/d per cow than that in CON group,respectively.Conclusion: the production performance and reproduction performance of SARA group were lower than CON group,and there was a positive correlated between SARA and laminitis.The cows in a negative energy balance state when the cows developed SARA,and happened liver injury.In addition,the greenhouse gas and nitrogen emission in the SARA group was higher than that in the CON group.Therefore,we could decrease the emission of greenhouse gas and discharge of manure from dairy cows by reducing the incidents of SARA. |
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