Effect of season on fertility of dairy cows in four US regions

摘要

In dairy cows, severe environmental conditions, such as heat stress during late gestation and early lactation, have been related to reduced subsequent milk yield and reproductive performance. Although these associations are supported by previous research, studies comparing the effect of season in multiple US regions are scarce. Here we analyze the association among season of calving and multiple indicators of fertility in multiple farms located in 4 US regions.