Making up for the heat

Do you tend to eat less in the heat? I do and so do our cows. This is the third day of hot weather here and there’s another on its way.

Once the mercury rises over about 25 degrees Celsius, the cows begin to find it uncomfortable. We’ve sent them to a shady paddock for the day and to make up for the fact that they’ll spend most of it under the spreading branches of the willows, we’ve also changed their feed pattern.

A cool spot for a hot day

According to the gurus at Cool Cows:

Cows will eat less overall, so increase the energy density of your diet where possible. More starch or added fat can be useful tools.

The risk of ruminal acidosis is increased during hot weather by several factors:

Cows prefer to eat in “blocks” in the cooler times of the morning and evening each day in hot weather;

Cows tend to select against low quality forage/fibre; and

The natural buffering system the cow relies on to combat ruminal acidosis does not work as well in hot weather.

Feeding of a high quality fibre source in the diet that helps maintain a stable rumen, but still contributes energy rather than just gut fill, is therefore essential in hot weather. For high-producing herds already being fed plenty of starch via grain / concentrates, this is particularly crucial.

Recent research work in Arizona (where they know a bit about heat!) suggests that heat stressed cows switch metabolism and have an increased need for glucose within their bodies. Feedstuffs and feeding strategies that either provide the cow with more glucose or spare the amount she uses in her normal body processes may therefore be useful in hot weather.

For these reasons, they’re getting some extra grass tonight in a fresh new paddock. What about the farmers? Lots of refreshing baths for baby Alex, the minimum of farm chores and an early morning sojourn into the cool forest.