Management adjustments to reduce heat stress in dairy cows

Management adjustments are aimed at reducing the exposure of cows to heat stress.

Changes in production systems

The most direct and most used measures include temperature and humidity control:

  • sprinkling cows with water
  • fans
  • shades
  • overhead sprays.

Younas et al. (1993) demonstrated that cooling and fanning brought a tendency for more preovulatory LH surges and higher oestrus response rate but had to be initiated several weeks before the planned breeding to give a significant benefit for the reproductive results. Their findings were confirmed by Bucklin et al. (1991) and Armstrong (1994).

Nutritional supplementation
Some benefits were observed when minerals,vitamin E and b-carotene were supplemented, especially when combined with cooling and fanning of the cows and pharmacological oestrus management. 

Arechiga et al. (1998) reported that timed AI in combination with b-carotene supplementation improved pregnancy rates during periods of heat stress in dairy cows. Supplementation with selenium and vitamin E was found by Arechiga et al. (1998) to have a beneficial effect on fertility in cows in hot environment. On the other hand however Ealy et al. (1994) reported that cooling improved pregnancy rates slightly in heat stressed cows, but supplementation with vitamin E had no evident positive effect on pregnancy rates.

shade for cows

Shade provided to keep dairy cows cool

mist spray

Dairy cows cooled by spraying with a water mist