Effects of Different Lactation Season,Parity and Lactation Stage on Milk Performance of Dairy Cows
To explore the effects of different lactation season,parity and lactation stage on milk performance and milk index of Holstein dairy cows in Ningxia.This study analyzed the effects of lactation season,parity and lactation stage on milk yield and milk composition of dairy cows based on 40977 production performance measurements from March 2022 to February 2023 in two pastures in Ningxia.The results showed as follows:the average daily milk yield of pasture A was 35.03kg,the average milk fat rate was 3.93%,the average milk protein rate was 3.36%,the somatic cell count was 22.15×104/mL,and milk urea nitrogen was 12.50%.The average daily milk yield of B ranch was 37.96kg,the average milk fat rate was 4.14%,the average milk protein rate was 3.54%,the average somatic cell count was 21.25×104/mL,and the average milk urea nitrogen was 12.50mg/dL.The lactation season had significant effects on the daily milk yield and milk fat scale of Holstein cows in the two pastures(P<0.05),and the daily milk yield of the two pastures was the highest in summer,while the milk protein percentage and milk fat percentage were higher in autumn and winter,and lower in spring and summer.Parity had significant effects on the daily milk yield and milk index of Holstein cows in the two pastures.The highest milk yield was found in pasture A on the second day of parities,and the highest milk yield was found in pasture B on the third day of parities,and the milk fat showed a decreasing trend with the increase of parity.There was significant somatic cell count between the two pastures(P<0.05),and the somatic cell count increased with the increase of the parity.Different lactation stages had significant effects on daily milk yield and milk indexes of cows in the two pastures(P<0.05).In both pastures A and B,the daily milk production gradually increased with the increase of lactation days,reached the peak in the peak period of lactation,and then gradually decreased with the increase of lactation days.The milk fat percentage of pasture A and pasture B was the highest at the beginning of lactation,followed by the end of lactation,and the lowest at the peak of lactation.The somatic cell count in early lactation of pasture A was significantly higher than that in other periods(P<0.05).In summary,the results showed that lactation season,parity and lactation stage had significant effects on milk performance and milk fat scale of Holstein dairy cows,and there were differences in daily milk yield and milk components among different pastures in the same area,which was related to the production management of dairy farms.In the practical production of dairy cows,many factors should be considered in order to give full play to the milk potential of dairy cows and increase economic benefits.
NETL
NSTL
万方数据
维普
