Heat stress will negatively impact reproduction. Some Florida producers stop breeding because conception rates drop below 5%. Possible reasons include:
- a 10 to 20% drop in dry matter intake,
- negative energy balance impacts blood hormone levels, and
- high body temperature may impact the fertile embryo, resulting in early abortion or lack of implantation.
Mike Hutjens, Extension Dairy Specialist, University of Illinois - Illini DairyNET