Fats & Proteins for Heat Stress

Higher producing cows and those under greater metabolic stress respond well to this nutritional strategy. Supplementary fat sources like vegetable oil and commercial ‘by-pass fat’ supplements are regularly used, while proteins provide a good source of amino acids.

How much fat during warmer periods?

Feeding fat has an added advantage in hot conditions - it is digested and used by the cow more efficiently than starches and fibre and produces less metabolic heat.

Too much fat interferes with microbial digestion in the rumen and depresses feed intake.

Aim for a maximum of 6-7% total fat in the diet (DM basis). Dietary supplementation with extra fat is a good way to help increase the energy density of the cow’s diet and maintain the daily energy intake.

Higher producing cows and those under greater metabolic stress respond well to this nutritional strategy. Supplementary fat sources like vegetable oil and commercial ‘by-pass fat’ supplements are regularly used.

It is important to manage the ratio of saturated versus unsaturated fats being fed in the diet.

In the US, diets used in hot conditions contain 3% fat from the main feeds in the diet, 2-3% fat from added vegetable oil and 1-2% fat as supplementary by-pass fat.

 

How much protein during warmer periods?

In hot conditions cows still need sufficient amounts of protein in their diet to maintain rumen microbial function and supply good flows of amino acids to the intestine. They are faced with three challenges;

  • Their daily feed intake is reduced.
  • Their rumen microbial function is compromised.
  • Summer pastures are lower in protein.

Feed higher-quality protein sources in the diet during the hot season. Higher ‘by-pass’ or ‘escape’ protein sources that are readily digested in the cows’ small intestine can help offset lower yields of microbial protein from the rumen during hot weather.