【Objective】The influence of different calving seasons and parity on test day lactation performance was analyzed for the adjustment of guidance of diet,increasing milk production and the scientific basis to enhance the quality of raw milk.【Method】The lactation performance contains 3012 test day milk yield,fat and protein,fat-to-protein ratio,SCS,and 305-day milk yield from 408 calving cows' DHI records.【Result Objective】The results showed that different calving seasons had significant effect on test day milk yield and 305-day milk yield(P0.01),but no significant effect on fat,protein,and FPR(fat-to-protein ratio).Parity also had significant effect on all the other lactation performance(P0.01) of cows except fat(P0.05).【Conclusion】The 305-day milk yield of calving cows in Ssummer and autumn were better.The lactation performance of the second to the third calving cows increased with parity,but reduced in different degree with the increasing of parity,especially after the 5th parity.

Body condition score(BCS) was the sign that evaluated raising quality and nutrient metabolism of dairy cow,and the one of the sign whether the cows were healthy or not.Body condition score provided important proof to make measures of breeding management for next stage and was affected by many factors as well.This study aimed at studying the factors including different parity,dry period and lactation period,the different stage of lactation influencing the body condition score.Data from 219 Chinese Holstein whose parity range from 0 to 6 were collected to determine body condition score in March 2009.The study analyzed the influence factor of body condition score including different parity,dry and lactation period,the different stage of lactation by SPSS15.0.The results showed that the different parity had no significant effect on BCS(p>0.05),the dry and lactation period had significant effects(p<0.01),the different stages of lactation had significant effects(p<0.01) on body condition score.Therefore,in actual practice,we should control the effect of these factors to body condition score in order to elevate the growth performance of Holstein cow.

观察了应用奶牛性控精液人工授精的不同输精时间、不同输精部位、不同输精月份的受胎效果,提出了进一步推广使用奶牛性控冻精的措施.