What dairy farmers must do to prepare for high temperatures

Now is the time for dairy farmers to carry out a cool review to assess heat load on the herd in different areas of the farm.

AHDB Dairy research manager Debbie McConnell says a “cool review” (see below for details) is a great initiative for this time of the year, as when temperatures reach 20C or higher, heat can affect cow dry matter intake and milk production.

This can also be exacerbated by high humidity so it is important for farmers to be aware of the temperature humidity index (THI) for both grazed and housed animals.

See also: Advice on how to keep dairy cattle cool

“It is very important for cows to have enough shade available in warmer weather. As all cows, particularly high-yielding ones, produce heat. Having a cooler place available helps them to be less affected by warmth,” she adds.

See also: Improve milk yields by focusing on lighting and ventilation

In addition to shade and distance to pasture, water is a crucial component in high temperatures and an assessment of water availability should be included in the review.

In extreme heat and depending on the farm set up, it might not be worth sending cows out to a distant paddock during the day between milkings if there is a closer one offering more shade.

In this case it may make more sense to sacrifice this field and offer high additional feed, that way the best paddocks  can be saved for overnight grazing when feed intakes are highest.

“A lactating cow needs a minimum of 70-100 litres of water a day, so access to a nearby drinker is crucial.”
Debbie McConnell, AHDB Dairy

“A lactating cow needs a minimum of 70-100 litres of water a day, so access to a nearby drinker is crucial.

“The flow rate also needs to be able to cope with the cows requirement as cows can drink up to 15 litres a minute at peak,” says Dr McConnell.

To help with this AHDB Dairy has produced a factsheet called Water at pasture and a booklet Effective use of water on dairy farms.

There may also be a requirement for additional salt in prolonged warm conditions due to the higher loss of sodium through raised respiration rate, increased perspiration and urination.

As the cow will be drinking more, sodium levels in the body may also be more diluted, so it would be useful to consult with the farm’s nutritionist, adds Dr McConnell.