9 Nutritional strategies to help cows against heat stress

For animals under heat stress conditions, the strict recommendation is to manage diet composition, properly supplement essential nutrients, consider timing and frequency of feeding and supply adequate water. But here are 9 more tips:

1. Concentrate-to-roughage ratio
Reduction in feed intake under heat stress may be recovered partially by increasing nutrient densities of diets. The metabolisable energy (ME) requirement for maintenance rises by 10–30% at 30–40°C compared with 18–20°C because extra energy is needed for heat dissipation. Therefore, by increasing ME intake (by increasing the concentrate-to-roughage ratio), more ME remains available for productive functions.

2. Protein nutrition
Feeding protein-deficient diets results in an increased heat load on animals due to increased heat production for the turnover of tissue proteins. Therefore, supplemental protein is needed to alleviate heat stress. Excess protein should, however, be avoided as it would be metabolised and excreted by the cow, a process that creates heat and consumes energy that could be used to produce milk.

3. Protected fat
It makes sense that enhancing ration energy density by utilising fats could be particularly beneficial during hot weather. However, research on the effects of feeding high-fat rations during hot weather has yielded inconsistent results. If fat is overfed, then the negative effects of the fat on fiber digestibility will negate any possible gains with increased ration density. As by-pass fats do not affect rumen fermentation, they should probably make up a greater percentage of the total fat included in the ration during hot weather.

4. Mineral supplement
Supplementation of minerals, particularly potassium (K) and sodium (Na) during heat stress is a highly recommended practice, because of the massive losses related to sweating during heat stress. Studies have shown some improvement in milk yield with 1.5% K and 0.38% Na but when the 1.5% K was combined with 0.67% Na, milk yields were superior.

5. Vitamin supplement
Different vitamins supply (such as niacin, vitamin C … ) can be recommended to support genral metabolism of animals submitted to heat stress. These vitamins can reduce oxidative stress, skin temperature, support vasodilation and milk yield.

6. Buffers
Diets should contain at least 0.75% sodium bicarbonate on a dry matter basis especially if the level of concentrate is high to mitigate the acidosis risk. This amounts to a minimum of 0.15 kg of buffer per day for a cow consuming 20 kg of dry matter.

7. Frequent feeding
As a further strategy, increasing feeding frequency should reduce heat production because this would promote a uniform rate of absorption of nutrients and spread the total heat increment due to feeding over a longer period. Frequent diet will support a good maintenance of rumen media, support a good absorption of nutrients, and avoid risk of disbalance.

8. Feeding time
By feeding cows in the early morning (5am to 6am), the heat of digestion peaks at 8am to 9am and allows the cow to dissipate some of that heat before the day gets hot. Similarly, cows fed during the evening will be more comfortable and likely to consume feed, and their peak of heat production will occur during the night when environmental temperatures are lower.

9. Water
In one study, the loss of water increased by 59% via the skin and 50% via respiration when ambient temperature increased from 18°C to 30°C. It is, therefore, important to provide cool, clean water ad libitum and eliminate any management factor that may inhibit cows from drinking. So, make sure to keep the water fresh, clean, and easily accessible!