Effects of preweaning calf daily gain and feed intake on first-lactation performance: A meta-analysis
Wen Jiang, Jingjun Wang, Shangru Li, Shuai Liu, Yimin Zhuang, Shengli Li, Wei Wang, Yajing Wang, Hongjian Yang, Wei Shao, Zhijun Cao
Abstract
This study aimed to investigate the effects of daily weight gain and feed intake of calves on first-lactation milk yield and composition using a meta-analysis. A total of 57 treatments from 18 studies were included in the study. Univariate and multivariate mixed models were constructed for calf ADG, liquid DMI (LDMI), starter DMI (SDMI), 305-d milk, milk fat, and protein yield data to gain insight into the effects of preweaning calf daily gain and feed intake on first-lactation performance. Univariate mixed models revealed ADG was significantly positively correlated with 305-d milk, milk fat, and protein yields during the first-lactation period. This indicates that ADG is a significant determinant of enhanced production performance during the first-lactation period. Furthermore, a significant quadratic correlation was observed between LDMI and 305-d milk, milk fat, and protein yields during the first-lactation period. The optimal performance during the first lactation was achieved when LDMI was maintained at 0.79 to 0.80 kg/d. In contrast, no significant association was observed between SDMI and production performance during the first-lactation period. Further multivariate mixed model analyses demonstrated that, when the effects of the 3 independent variables were considered collectively, only ADG exhibited a significant positive effect on 305-d milk yield and fat production during the first-lactation period. However, the modeling of milk protein yield revealed that ADG and LDMI exerted a significant influence, whereas the effect of SDMI remained insignificant. This study emphasized the significant effect of ADG and LDMI in optimizing the future lactation performance of calves, providing a crucial foundation for the development of scientific feeding management strategies.