Correlation Analysis Of Milk Production Performance And Milk Compositions Of Binglangjiang Buffaloes Under Different Thermal Environments

Buffalo milk contains more nutrients such as milk fat,milk protein,unsaturated fatty acids and trace elements than ordinary milk,and it is an important raw material for making dairy products such as double-skinned milk,yogurt and cheese,which is loved by consumers and has a broad market prospect.As the only river type buffalo found in China,and their heat resistance are greatly poor.To reveal the effects of different thermal conditions on milk performance,it will provide theoretical support for its environmental management and nutrient supply for dairy buffaloes.In this study,the milk composition of 74 milk buffaloes was measured by Combi Foss FT+ milk composition and somatic cell online analyzer.Combined with the collected meteorological data,the influence of different thermal environment and rainfall on lactation performance was analyzed.The main results are as follows:(1)To investigate the effect of temperature on milk yield and milk composition of Binglangjiang buffaloes,average temperatures are divided into three groups,low(5°C～10°C),medium(10°C～15°C)and high(15°C～20°C).The results showed that different temperatures had significant effects on milk fat percentage,milk protein percentage,and non-fat solids(P < 0.05),but not on daily milk yield,lactose percentage,total solids,somatic cell fraction,and urea nitrogen(P > 0.05).(2)In this study,we analyzed the effect of relative humidity on milk production and milk composition of Binglangjiang buffaloes.Relative humidity was divided into four groups,1(60%～70%),2(70%～80%),3(80%～90%)and 4(90%-100%).The results showed that relative humidity had significant effects on daily milk yield,milk fat percentage,milk protein percentage,total solids,non-fat solids and urea nitrogen(P <0.05),and no significant effects(P > 0.05)on lactose percentage and somatic cell counts in Binglangjiang buffaloes.(3)In this study,THI(Humidity-temperature index)was divided into two groups,low THI group(< 55)and high THI group(≥ 55).The results showed that THI had a significant effect on milk non-fat solids and somatic cell fraction(P < 0.05),but not on daily milk yield and milk fat percentage,milk protein percentage,lactose percentage,total solids and urea nitrogen content in milk(P > 0.05).(4)The year was divided into four seasons: spring(March-May),summer(June-August),autumn(September-November)and winter(December-February).The results showed that season had no significant effect(P > 0.05)on daily milk yield and lactose rate in milk of Binglangjiang buffaloes,but significant effects were detected on milk fat rate,milk protein rate,total solids,non-fat solids,somatic cell counts and urea nitrogen content in milk(P < 0.05).(5)To investigate the effect of precipitation on the lactation performance of betel nut buffaloes,this study classified precipitation into three groups(low(< 5 mm),medium(5 mm-10 mm)and high(> 10 mm).The results showed that rainfall had no significant effect(P > 0.05)on daily milk yield and milk fat,milk protein,lactose and non-fat solids in milk,but it had significant effects on total solids,somatic cell fraction and urea nitrogen in milk.In conclusion,temperature,rainfall,THI and season had no significant effects on daily milk yield(P > 0.05),but relative humidity had significant effect on daily milk yield(P < 0.05).Whereas,temperature,relative humidity,THI,season and rainfall had significant effects on milk quality(milk fat percentage,milk protein percentage,lactose percentage,total solid matter,non-fat solids,somatic cell count and urea nitrogen)of Binglangjiang buffalo(P < 0.05).