| Data were collected from Sanhe(Langfang), Jingming(Qinhuangdao), Shuangwa(Tangshan) and Hangu(Tianjin) cow farms, containing records of 19,744 DHI inspection datum for 1,492 Hostein cows(188 cows in Sanhe farm,252 cows in Jingming farm, 863 cows in Shuangwa farm and 479 cows in Hangu farm)between Jan.2007 and Oct.2009. Combining the basic data including the birth date, the parity,the calving date, the test date as well as making full use of computer technic to bring forth all kinds of reports, including produnction reports, somatic cell countent analysis reports and milking curve reports and adjusting indix of lactation days for 305d milk yiled and DHI data analysis repotrs, at last, the systematic, complete and scientific suggestion and measures will provide services to cow management, breeding and desease prevention and will be offered to the cow farms to solve the problems during the production and management promptly. Besides, the genetic evaluation of breeder value was made using least square method and repeadability model BLUP. The fixed effects, the permanent random enviromental effects and animal additie genetic effects of milk yeild, fat percentage, protein percentage and somatic cell countent (somatic cell score) were calculated for every individual in the model. Animals were ranked according to the China Performance Index(CPI). Perfect cows were selected for each cow form as the nucleus herd. This can make a good base for cows breeding improvement and bull selection.The results suggested that a great achivement has been made since the DHI system was applied in the three years in Hebei provence. Results shows that the SCC significantly dropped. The largest decline with the decrease of 54.87% has been found in Jingming cow farm, SCC reduced to 613 300/ml form original 1,358 900/ml. While the smallest decline with the decrese of 5.80% has been found in Shuangwa cow farm, SCC reduced from original 690 000/ml to 650 000/ml, which is slightly higher than the critical value of the domestic subclinical mastitis 500,000/ml. The daily output of each cow has enhanced significantly.The largest increase with the rise of 57.07% was found in Jingming cow farm, the daily output of each cow reached to 28.90 kilograms at present from 18.04 kilograms in the past.The smallest increase of 7.95% was found in Sanhe cow farm, the daily output of each cow reached to 24.55 kilograms at present from 22.74 kilograms in the past. There is no obvious improvement for the ratio of milk fat and milk protein.The results of the Least Squares model suggest that herd, caving year and seasons and the parities all affect the production performance. Recently, milk yield was in a stable upward trend while the SCS was in a downward trend. The 305d milk yield of different calving yaer increased from 6407.69Kg of 2006 to 8052.68Kg of 2009, and there is an extremely significant difference between them (P<0.01), while the SCS decreased from 3.71 of 2006 to 2.18 of 2009, and they were significant different (P<0.05). Summer had the most negative effect on production performance, which can attribute to the heat stress that cause a high level of SCS. The SCS rised to 4.15 level in the summer calving season, which is the highest level of the four seasons, and was significant different from other calving seasons. In addition, milk yield did not show an increasing trend with the parity increased, but the highest output is in the second parity; calving years and the parities effects on the rate of milk protein did not reach a significant level, while herd and calving seasons effects did. The four fixed effects all extremelly affected the persentage of milk fat.By the repeatability animal model and performance index(CPI)calculation, the first three bulls arrayed by CPI were 2790 11190520 and 11102919, besides 2790 comes from Qinhuangdao, the other two both come from Beijing dairy center. Their CPI were 2391.99, 1326.76, and 1048.75, respectively. Select cows with CPI index in the top 1/3 of each herd as a nucleus herd for the four farms respectively.
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