Yep, it’s a heatwave. Dairy cows hate heatwaves. How much? Take a look at some of these weird facts from Dairy Australia’s Cool Cows website:
- Each of our dairy cows gives off body heat equivalent to a 1500-watt hair dryer on a hot day.
- Cows eat 10-20% less when the air temperature is more than 26°C.
- A cow making more milk is more easily heat stressed.
- Each dairy cow can drink 200-250 litres per day in hot weather – double the normal intake.
- A heat stressed cow makes less milk for one to two days afterwards. If she’s heat stressed for two days in a row, milk production can be affected for a fortnight.
Suffice to say, the weatherman has our attention. Farmer levies fund a Temperature Humidity Index (THI) forecast that gives us a heads-up on just how tough it could be on the cows.
A THI of over 68 has a measurable impact on milk production, not to mention our cows’ wellbeing. As you can see, the forecast has us reaching a THI of 83. Nasty.
THI Dairy Forecast http://dairy.katestone.com.au/
We’re onto it. To help keep the cows cool, we milk earlier in the morning and later in the afternoon when the sun is low.
The cows have a paddock with enough shade and water for everyone that’s close to the dairy. We serve up a light meal of silage just beyond the trees, so they can sneak out from the shade, have a nibble and go back where it’s cool for a nap.
The dairy yard is sprinkled with water, giving the cows a welcome shower while they wait to be milked. Inside the dairy, ceiling fans whir above the cows for maximum comfort.
There are three water troughs on the way to the night paddock, which is a juicy crop of emerald-green millet. Better than being at the beach!
Remember yesterday’s 41 degree Celsius heat? Now, imagine you were standing outside in it being blasted by 250 1500-watt hair dryers. How do you feel now? Ready to do athletics?
Icy poles for cows
Believe it or not, each of our dairy cows gives off body heat equivalent to a 1500-watt hair dryer on a hot day. Yet, incredibly, each still made an average of 29 litres of milk for us yesterday. We nursed them through with some very careful planning based on the principles of the Cool Cows program.
- Wayne got up an hour earlier to milk before the sun’s rays began to sting and milked two hours later than usual. This meant that the cows spent less time in the sun on the concrete yard waiting to be milked.
- We hosed the whole yard down about 45 minutes before the afternoon milking. It’s amazing how much cooler the yard felt afterwards.
- The yard sprinklers were activated as the cows came towards the yard. (You remember the fun of dancing through sprinklers on the lawn!)
- The cows’ diet changed a little for the day. The cows got a little more grain, a little more green crop and a little less hay yesterday. It takes more energy to digest high-fibre foods, which adds to heat stress. Rather than feeding out the hay during the day, Wayne stayed up late and offered the cows a “night-cap” in the relative cool of the evening.
- We chose the coolest paddock on the farm, ringed by the deep shade of mature willow trees.
- On a hot day, dairy cows can slurp up a staggering 250 litres each. Our extra-large troughs ensured they had plenty of fresh, cool water to drink when they chose to emerge from their hideouts.
Poor girls. According to the Cool Cows program leader, Dr Steve Little, dairy cows start to seek out shade when it gets to about 25 degrees C. I think the farm’s cows, dogs and humans all felt the need to go into summer hibernation yesterday.
By far the coolest animals on our dairy farm are the 2 year olds.
Just kicking back
With the fearlessness and carefree existence of youth, these girls really know how to relax!
“Cool” is also the understatement of the month for Spring 2012. The area set aside for revegetation is earning its sexy NRM-funding title of ‘ephemeral wetland’ with more regularity than I would like.
Does this count as the fifth flood of 2012?
On the other hand, the grass is growing in between inundations. If it would just stop raining for a couple of weeks, we might get some silage tucked away for summer!
Mother duck speeds her charges away from the cow track as the herd passes by.
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.
A cool place to hang out
Our cows are dignified ladies who like to keep their cool in more ways than one. Bred in cooler climes than Australia, Holstein Friesians start to feel the heat once the mercury climbs over 25 degrees Celsius.
We’ve been really busy preparing the farm to help them deal with hot summer days:
- planting thousands of trees for shade
New plantations will provide shade for the cows and corridors for wildlife
- installing 4 kilometres of large capacity water pipes and 17 massive water troughs. Milking cows can drink up to 250 litres each on a hot day or 20 litres in a minute!
Installing water troughs has been a 3 year project
- putting up sprinklers in the dairy yard to offer a cool shower while they wait to be milked and
A shower cools the cows, the concrete underfoot and offers relief from flies
- adding salt, minerals and zinc to their diets.
Zinc is added to the cows' feed during summer
I also select the paddock for the day with a keen eye on the forecast. Today is pretty uncomfortable, so they’ve been sent to a paddock ringed with trees and will graze a more open paddock tonight.
Cool cows are happy, healthy cows who make more milk, suffer fewer illnesses, carry pregnancies better and are nicer to work alongside! Dairy research body, Dairy Australia, has done lots of work on heat stress in dairy cows and you can access lots of useful info at the Cool Cows website.