| This study of 2012~2017 years of Shaanxi Guanzhong four cities(Xi'an,Baoji,Xianyang,Weinan)into dairy farms in the province's dairy production performance measurement was investigated,and field sampling,in the province of Shaanxi dairy cattle center sample processing and analysis based on DHI data through measurement and Testing Center Access to the farm group production management records,obtain milk composition(milk protein percentage,fat percentage),body cell,urea nitrogen,parity and other data,and the 1738344 DHI data collation and analysis.To understand the scale of dairy feeding management,diet and health care aspect ratio,breast disease prevention etc.the successful experience and existing problems,a comprehensive summary of the Shaanxi dairy group genetic improvement effect.The study obtained the following conclusions:First,from 2012 to 2017,four,average daily milk yield in different dairy group,the quality has been optimized,the amount of milk cows,Nissan 35 kg average proportion reached more than 46%,the highest reached 48.79% in 2016 to 2017.Daily milk yield than 15 kg cows than for an average of about 5.35% from 2016 to 2017,the lowest for 4.85%.The average daily milk yield by 22.12 kg growth in 2012 to 36.09 kg in 2017.The increase of 7.97 kg,an increase of 36.03%;the average milk fat rate increased from 3.83% in 2012 to 4.01% in 2017,an increase of 0.18 percentage points,an increase of 4.70%;the average rate of milk protein increased from 3.21% in 2012 to 3.39% in 2017,an increase of 0.18 percentage points increase.5.61%;the average number of somatic cells from 2012 622 thousand and 100 to 2017/ml 225 thousand and 800/ml,/ml decreased 396 thousand and 300,a decrease of 63.70%,the average urea nitrogen from 7.26mg/dl in 2012 to 15.58mg/dl in 2017,8.32mg/dl growth,an increase of 114.60%.Two,the average daily milk yield of dairy cows has increased first and then decreased during the whole lactation dairy cows 100D~199d,the average daily milk yield was 31.22 kg,significantly higher than that of 1D~44d,45d~99d,200D~305d,the average daily milk amount of the four stages of >305d(P <0.01 >305d),the average daily milk yield of cows 19.63 kg was significantly lower than that of 1D~44d,45d~99d,100D~200D~199d,the average daily milk amount the four stages of 305d(P<0.01);with the increase of parities,decreased in 2 fetuses after the average daily milk yield of the second fetal average daily milk yield the highest(35.13kg),sixth fetal average daily milk yield was the lowest(24.09kg).Three,the average cow milk fat rate with advancing lactation days have increased first and then decreased.Among them,1D~44d average milk fat rate is the lowest(3.81%),200D~305d average milk protein was the highest(3.88%),and 200D~305d average milk fat percentage was significantly higher than that of 1D~44d,45d~99d,100D~199d >305d,the four stages of the average milk Fat rate(P<0.05);the average rate of 1~6 fetal cow milk which is more than 3.80%,and the average milk fat 2 fetal rate was the highest(3.96%),the average milk fat 1 fetal was the lowest(3.81%).Four,the average rate of cow milk protein with advancing lactation days have increased first and then decreased.Among them,1D~44d average milk protein was the lowest(3.14%),200D~305d average milk protein was the highest(3.25%),and 200D~305d average rate of milk protein was significantly higher than that of 1D~four stages 44 d,45d to 99 d,100D to 199 d,>305d The average rate of milk protein(P<0.05);the average cow milk protein rate with the increase of SCC has increased firstly and then decreased,the average milk protein 5 fetal was highest(3.34%),the average milk protein 1 parity was the lowest(3.16%).Five,the average cow somatic cell count was firstly decreased and then increased trend,during the whole lactation,45d~99d average number of somatic cells was highest(510 thousand and 500/ml),200D~305d average somatic cell count of the lowest(365 thousand and 800/ml);the average cow somatic cell count with the increase of SCC are on the rise,among them,first fetal minimum(261 thousand and 700/m L),the highest in sixth fetuses(595 thousand and 600/ml).Six,the average urea nitrogen content of dairy cows with lactation days advance a downward trend,the average 1D~44d urea nitrogen content was the highest(15.48mg/ml),200D~305d average urea nitrogen content was the lowest(9.42mg/dl),differences in the average content of urea nitrogen and 200D~305d and other phases significantly(P<0.05)cow;Ping Both urea nitrogen content with the increase of SCC,urea nitrogen content has a rising trend,among them,3 fetal blood urea nitrogen content was the highest(16.65 mg/dl),6 fetal blood urea nitrogen content was the lowest(9.29 mg/dl). |
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