With summer well underway, here are some heat management strategies that can be implemented to look after your cows and minimise production losses during these periods.

Provide plenty of shade and water

Shade is the most effective way to reduce heat as it blocks solar radiation and can reduce the radiant heat load by 50% or more. Make sure cows are placed into paddocks with plenty of shade and water available. This may involve sending the cows to a paddock to graze early in the morning and then moving them to a shaded part of the farm during the heat of the day, however walking should be kept to a minimum where possible.

Make sure water troughs are big enough to allow multiple cows to drink at once and that the input of water can keep up with the cows consumption rate. An average sized cow can drink anywhere between 170-200L/day during periods of extreme heat.


When cows are hot, the best way to eliminate heat is through the use of sprinklers for evaporation as they have the ability to dissipate 2200 BTU (British thermal unit) of heat for every 1L of water that evaporates from the skin of a cow’s body (Zulovich, 2018).

Medium to course sized droplets should be distributed and should soak the whole area of the cow yard. Sprinklers should be used during both the am and pm milkings. Cooling the cows during the morning milking will help keep their body temperature lower during the day for longer, allowing them to graze for a longer period of time after the morning milking. During the pm milking, sprinklers will allow the evaporation process to occur and reduce the cows overall body temperature that has been elevated through the course of the day from exposure to the radiation. Dairy Australia recommends that the following sprinkler cycle should be set up to cool cows most effectively in the yard; 1.2L water/m2 for 3 mins on and then 12 minutes off.

Increase quality of feed

Cows start to stress when temperatures reach above 25 degrees and therefore intake of dry matter (energy) can decline as much as 10-20% in extreme temperatures. Protein tests will typically drop over these extreme heat periods as it is directly related to intake. To minimise production losses, make sure high-quality feeds are on offer to the cows straight after milking, which is when their intake is at its highest. By feeding high quality feeds such as Lucerne hay or extra kg of grain, the cow is able to get more energy and protein from every mouthful and won’t be required to eat large quantities of fodder. Along with intake reductions, the cows use more energy through panting and trying to cool herself and maintenance requirements can increase by 20-30%. The use of additives such as betaine or yeast in your grain ration can also be of benefit during these periods.

Reduce walking distances

Where you can, try to put cows in paddocks near the dairy to minimise walking distances for the girls, which will reduce stress levels and prevent extra energy losses. This may involve the use of a sacrifice paddock and feed of a high quality being brought to the cows to eat.

Alter milking times

Try moving your milking times forward in the morning so that cows have longer to graze/eat prior to the heat setting in. Push the pm milking time back so that the cows can be left in the paddock with the shade and not standing in the yard during one of the hottest parts of the day.

This is just a brief overview of some of the strategies that can be used and I understand that every farm is in a different situation and has different infrastructure, so not all will be applicable to everyone. Our team are more than happy to have one-on-one discussions should you want to discuss heat stress management strategies and how we can try to personally reduce production losses on your individual farm.

For further information on how to manage heat stress and minimise production losses then please feel free to get in contact with a member of the Sales & Nutrition team.

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