Crossing Bos indicus and Bos taurus was expected to produce more productive and adaptable progeny, but contrary to expectations, their crossbreds are prone to several reproductive disorders, and poorer reproductive qualities. The research about the reproductive quality between two species showed different result. The aim of this research is to compared the reproductive quality of Bos indicus crossbred and their crossbreds with Bos taurus. A meta-analysis involving 43 studies on reproductive hormone levels, 25 studies on estrus activity and 65 studies on reproductive performance. Article search, article selection, data extraction, statistical analysis (heterogeneity, summary effect, publication bias test) were used in this meta-analysis. Statistical analysis was supported by Open MEE and R Studio. The results show that Bos indicus have lower progesterone levels in the proestrus phase compared to their crossbred with Bos taurus, but no significant difference in other reproductive hormone levels. This also occurs in estrus activity parameters, where there is no significant difference in the estrus cycle and duration between Bos indicus cattle and their crossbred with Bos taurus. No significant differences in several reproductive parameters due to adaptation or resistance to stress. The increase in progesterone levels during proestrus phase on crossbred cattle is the reason for the occurrence of delayed ovulation, thus requiring external hormone intervention. Based on the finding, Bos indicus crossbred cattle are more recommended to be raised in tropical areas with high environmental temperature. Further meta-analysis that categorized the reproductive quality of crossbred cattle based on the location altitude, feeding management, age and/or parity, needs to be conducted to determine the most optimal rearing conditions.
Keywords | Crossbred cattle, Meta-analysis, Reproductive parameters