Can thermoregulatory response to heat stress be improved in lactating dairy cows? Insights from counter-current heat transfer systems impacting reproduction.

Climate change has caused heat stress (HS) to become an increasingly severe problem for high-producing dairy herds. Although cooling systems allow milk production to remain nearly constant throughout the year, fertility decreases during summer. Physiological counter-current heat transfer mechanisms maintaining brain/hypothalamic and reproductive functions in cattle are vulnerable to HS. In this study, I propose strategies to improve cooling systems, particularly in zones with the highest risk of increased body temperature, such as milking areas. In addition, heat transfer mechanisms to protect the brain-hypothalamus axis from hyperthermia must be considered when implementing measures to reduce HS-related problems.