Correlation Between Milk Yield And Composition In Chinese Holstein And Their Effects In Huanggmei County

So far,although there are many scientific reports about cow milk composition and their influence factor all over the world,but they have big difference.Huangmei city in Hubei province is a recently developing city with few experience in feeding and management of dairy cows.Moreover,the local environment and geography,agricultural ecosystem and production performance of dairy cows are different from other places such as Wuhan and Northern China.In order to make better analysis and extention of DHI technique,improve management level and milk quality,we collect the records about dairy herd improvement(DHI)at a farm belonging to Hubei Huangmei Modern Husbandry Ltd.which is the biggest in population of cows in Huangmei city to analysis the correlation between milk yield and composition,as well as the effect of lactation period,parity,days in milk,calving season and lactation month.The purposes of this study is to focus on extention of DHI technique and establishment of reasonable management steps to improve the milk yield and quality.Our aim is to instruct the management of this year through making some analysis from DHI data in 2016.The research contents and results were shown as follows:1.Correlation between milk yield and milk compositionMilk yield has significant negative correlation with milk fat,milk protein,somatic cell score,total solids(r=-0.168,-0.249,-0.095,-0.179,p<0.05),milk yield has significant positive correlation with urea nitrogen,milk lactose(r=0.050,0.153,p<0.05).2.Correlation among milk compositionMilk lactose has significant positive correlation with milk total solids(r=0.026,p<0.05)and positive correlation with milk protein(r=0.003,p>0.05),milk lactose has significant negative correlation with milk fat,somatic cell score,urea nitrogen(r=-0.140,-0.152,-0.030,p<0.05),total solids has significant positive correlation with milk fat,milk protein,urea nitrogen(r=0.935,0.532,0.091,p<0.05),total solids has positive correlation with somatic cell score(r=0.001,p>0.05).Milk fat has significant positive correlation with milk protein,urea nitrogen(r=0.270,0.195,p<0.05),Milk fat has positive correlation with somatic cell score(r=0.009,p>0.05),milk protein has significant positive correlation with somatic cell score(r=0.097,p<0.05),milk protein has significant negative correlation with urea nitrogen(r=-0.100,p<0.05),somatic cell score has correlation with urea nitrogen,their significance is not very much(r=0.008,p>0.05).3.Factors inference milk yield and compositionLactation season,parity,days in milk and lactation month all have significant influence on milk fat,somatic cell score,urea nitrogen,total solids,milk yield,milk protein,milk lactose(p<0.05),calving season has significant influence on somatic cell score,urea nitrogen,total solids,milk yield,milk protein,milk lactose(p<0.05).