Investigation Of Milk Production And Reproductive Performance Of Dairy Cows In Five Dairy Farms Of Jiangsu Province

Cow farm production efficiency is mainly affected by the level of milk production and reproductive performance.Besides,milk production and reproductive performance are affected by many factors,such as genetic background,nutrition levels and ranch environment.In this study,five farms were selected to be the experimental farms.Field research was carried out to collect dairy herd improvement data,breeding records,eliminated records,disease diagnosis and treatment records from 2011 to 2015.These data were deeply analyzed to find out the factors that may affect milk reproduction performance and reproductive performance.From the statistical analysis,these following results are obtained.From the investigation of milk production,the second and the third parity of dairy cows have better performance than other parities.305 days milk yield of cows with primiparous months between 24-26 months is significantly higher than others(p<0.05)and somatic cell count was significantly lower than others(p<0.05).Cows can maximize their milk production potential at this stage.Milk production and quality of cows calving in summer are as expected.From the investigation of reproductive performance,seasonal variations of reproductive performance of dairy cows are found.Reproductive performance indicators,such as conception and abortion ratioes,are significantly lower in summer than in autumn and winter(p<0.05).Therefore,it is necessary to adjust breeding plan to avoid breeding or calving during summer.From the investigation of elimination reason of cows,a large portion of eliminations are passive in this farm and the elimination rate of suitable production gestation cow is too high.Breasts problems are the main factors causing elimination,mostly of which due to mastitis.360 days later,0-30 days and 150-180 days of lactation are the phases that eliminations happen more frequently.