Temperatures above 26 °C will start to negatively affect a cow’s ability to produce milk. Intakes can reduce by more than 20%, usually because the cows seek shade rather than graze. Blood flow throughout the body is diverted to the skin to aid cooling, this can effect:
- Absorption of vital nutrients from the gut
- Milk production
- Reproduction
Signs of heat stress include :
- Increased breathing rate (more than one breath/sec)
- Seeking shade
- Crowding around/in the water source
- Panting
- Recumbancy – Down Cow
- Excessive salivation
- Collapse
- Death
