Effects Of Calving Season,Parity and Their interaction on Lactation Performance of Holstein Cattle
In order to clarify the effects of different calving seasons,litters and the interactions be-tween calving seasons and litters on lactation performance of Holstein cows,and to provide a theoretical basis for the management of large-scale dairy farms,a total of 276 603 DHI data were collected from four dairy farms in Ningxia from 2019 to 2021,and Wood model was used to fit the lactation curve for different calving seasons(Spring:March to May,Summer:June to August,Autumn:September to November,Winter:December to February),parity(1,2,3,4,5 to 7)and their interaction.The results showed that the fitness degree(R2)of group lactation curves of Wood model ranged from 0.9326 to 0.9774 in different parities,from 0.9571 to 0.9714 in different calving seasons,and from 0.7777 to 0.9917 in different calving seasons and parity interactions.The parameters of Holstein population lactation curve were extremely af-fected by parities,calving seasons and the interaction between parity and calving season(P＜0.01).The parturient cows reached the peak lactation in 3 months after delivery,which was slightly earlier than that of the primiparous cows,and the peak lactation time was similar in different parities,and the milk yield reached the highest at the 4th parity.This study revealed the lactation rules of Holstein cattle in different calving seasons and parity,which could provide a theoretical basis for the management of large-scale dairy farms.
万方数据
维普
