Heat stress and its effects on milk production are commonly related to the effects of climate change. In the temperate regions, cold winters and mild summers have historically provided some buffering effect and maintained milk production. However, a measurable effect of heat stress on milk production was found, with its severity and period dependent on microclimates and the rate of increase dependent on climate change. Taking central Europe as an example area, the length of summer heat stress period was found to vary between 2 and 4 mo in a year. Furthermore, the continuous period of heat stress was found to be expanding into the months of May and September. Heat waves were found not to increase the length of the heat stress period, but rather to make it more severe. Milk production was found to decrease in locations with increased heat stress.

Read the full article in the Journal of Animal Science.