Summer cooling strategies for dairy cattle

With the days getting longer and hotter, cattle are going to become increasingly uncomfortable and may even experience heat stress due to the heat and humidity. In the fourth and final segment of this podcast series, UW-Extension and industry discuss ways you can keep your cattle cool all through the summer.


Liz Binversie, UW-Extension Brown County Agriculture Educator


Mark Mayer, UW-Extension Green County Agriculture Agent
David Kammel, UW-Madison/UW-Extension  Biological Systems Engineering professor
Dr. Vicky Lauer, Professional Services Veterinarian, ANIMART


Time: 7:16 minutes


Liz Binversie: Greetings, I’m Liz Binversie, Agriculture Educator for UW-Extension in Brown County, Wisconsin. In our fourth and final segment of the heat stress and facilities consideration podcast series, we will talk about strategies producers can use to keep cows cool in the summer, as well as our calves and heifers, so we can keep the entire herd healthy and productive. On the panel today is David Kammel, Biological Systems Engineering Professor for UW-Madison and UW-Extension, Mark Mayer, Agriculture Agent for UW-Extension Green County, and Dr. Vicky Lauer, Professional Services Veterinarian for ANIMART.

We talked earlier about how the herd needs to keep body temperature in a comfortable range to prevent heat stress. What are some things that producers can do to keep the herd cool that won’t break the bank? Along those lines, Mark what are some cost effective solutions to help keep the entire herd cool this summer?

Mark Mayer: Certainly providing shade is important. That’s done in most freestall barns but if cows are out on pasture, you want to provide 45-50 square feet per cow for shade. That really helps with the solar heating in the summer, and of course having some air movement, some ventilation in the barns as David discussed earlier. I just want to mention the sprinkler systems with milk cows, they become very popular. Water actually sprinkling cows is more effective than just using fans, and using fans with sprinklers is most effective. One mistake that I see is that a lot of farmers do is that most don’t turn these systems on soon enough, number one, but they don’t have the right timing. One thing you definitely don’t want to use is mister hoses because it creates a fine mist, it actually creates a barrier on the cow’s hair coat and she can’t rid of heat and it makes things even worse. So if you use a sprinkling system, you want to make sure you’re using a low pressure system that creates large droplets, runs for maybe 2-3 minutes, and then is off and fans are running for the next 12-15 minutes, and then when you get to really higher temperatures over 90, you may want to have them sprinkle every 5 minutes and increase that but definitely want to use large droplet size so you wet the hide and we don’t want to wet the cow entirely. We really do not want to see that udder getting wet, the shoulders and back. If the cow’s dripping off the udder, there’s probably too much water being used, and, of course, make sure you use ventilation because adding that water to the barn is going to increase the humidity in the barn as well. David, do you have anything to add?

David Kammel: Yeah, thanks Mark, I use the acronym of SAW, S-A-W. Shade, air, and water. Now Mark covered every one of those in his description. I would mention that in those sprinkler system, reinforce the idea that you need large droplets. We’re going to sprinkle the cows over the feed platform because it’s probably the most convenient place to sprinkle them but you can also sprinkle cows over at the return lane. People sprinkle cows at the holding area. Again that’s another good way to help the holding area heat stress situation is just sprinkle them there. It’s a convenient place to do it. It’s a confined place to do it, so you don’t maybe waste as much water as you might in a freestall barn, but you want to have that wet-dry cycle. They got to get wet, they’ve got to be able to dry off. Adding fans to any of those sprinklers are going to help increase that ability to evaporate water off their bodies. They’ve got a huge amount of surface area and we want to take advantage of that. When we put air over the cows with velocity fans, probably the first thing is farms do a lot of times have velocity fans. My experience is usually there’s not quite enough of them and they might be over the wrong places, so sometimes the spacing is too far apart, so you have these dead zones between the velocity fans that some cows aren’t going to get the full benefit of that velocity, some cows do. We want to have air over the beds where they’re resting, and we want to sprinkle them at the feed bunk. When we first started looking at heat stress mitigation techniques, a lot of farms would put sprinklers over the feed line and then put fans right over the feed line as well and that did create a really nice environment for the cows and the cows figured that out. They figured it’s a lot nicer and cooler if I got done eating but I still stand at the bunk instead of go lay down in a hot, still freestall bed. I’m going to stand here by the sprinklers and the fans because this is the most comfortable place in the barn. So we kind of created our own problem. We created a microclimate that was really good for cow cooling but it was at the wrong location. So we have to kind of spread the cows. To get the cows spread out we put water over at the bunk, we put the fans over the beds that they’re resting on, so they can walk away and still get the benefit of that cow cooling. When we’re putting in fans, as far as being a cost effective solution, we should be buying fans that have been tested, that have a certain energy rating, so many cfm per watt of energy used, rather than buying fans that haven’t been tested. In the long term, you’re going to save money on your electric bill. They’re going to last a lot longer. And the number of fans that you will need will probably be reduced if you know what those fans can produce and that they’re going to be effective at creating the velocities that you’re looking for. Dr. Vicky would you like to add any comments?

Dr. Vicky Lauer: The one option to help with heat stress in calves is to work the calves in the morning. Whether you’re vaccinating, dehorning, whatever, that will help minimize the effects of heat on them. Then if you’re using hutches, some clients are actually putting sand bedding into those hutches and that helps keep those calves cool because it’s nice inorganic matter. It also helps keep the flies down. They’ve done some studies and shown that shade is very helpful and placing that over the hutches will help keep those hutches cooler. If shade isn’t an option, then position those hutches to take advantage of all prevailing winds. Open all the vents in the hutches, and then place a concrete block under the back wall. This will help optimize ventilation through those hutches. In calf barns, you should definitely increase ventilation just like in the adult cow barns by using velocity fans or by using a positive pressure ventilation system that’s designed for the summer. That will actually draft those calves and keep them nice and cool.

Liz Binversie: Thank you again to our wonderful panel today. If you have questions or would like to reach any of our panelists, you can reach them by email.