Calf jackets, should they stay or should they go?
Did you put a hoodie on this morning before you walked to the barn? Here in NE WI, I sure did! Because it was 39F when I went out this morning. Now, what about your calves? Did they have their hoodies on this morning too?
Spring and fall are a tricky time of year. The temperature swings are large and typically a daily occurrence no matter where you live, even without factoring in the humidity, wind, and any other weather we might happen upon (aka the snow storm we got April 3 this year.
Calf jackets can be a huge asset to a newborn calf, but when is it time to stop using them for the year? This question isn’t as cut and dry as you might hope, but here are a few pointers to consider when you should and shouldn’t be using calf jackets.
As a reminder, a calf that is less than 30 days old has a thermal neutral zone from 55F to 78F. When they get to around a month (when they start ruminating), that zone drops to 32F to 73F. When calves get outside of that temperature zone, it causes them to start using calories to either heat or cool themselves.
It’s also important to note that at birth, calves only have 3-4% brown fat, which is the fat that keeps them warm, and also the fat that they will use up quickly when they are trying to warm themselves up.
When discussing thermal neutral zones, it’s important to consider all factors that are affecting the calf in the environment she is in. The best way to test if a calf should have a jacket on or not, is to roll up your sleeves and go sit in her pen for at least 30 minutes, to get to a resting body state, remember, she doesn’t work for a living!
If you aren’t able to do that on a daily basis to check the weather where she is (even though 30 minutes of meditation per day does have a lot of health benefits), you’ll have to think about all of the factors that are affecting her and make a choice from there. Here are a few things to consider.
Humidity. One comment many people make about being in the Midwest or North East is that the right weather will chill you to the bone. It might say it’s 40F outside, but it will feel like it’s 20F. Humidity plays a huge factor in how it feels outside and in your barn, especially if the sun isn’t out to help heat things up.
Following that up, sunlight makes a huge difference on calf warmth. If they are in the direct sun, they will get nice and warm, and maybe even too warm in the middle of the day. But, if they are in a calf barn, and don’t regularly get sunlight, that will change how warm she gets during the day.
Wind/ventilation. As you know, air movement creates heat abatement. Make sure to factor that into the overall temperature of the calf’s environment.
Newborn calves are wet, being wet will significantly change the thermal neutral zone (think about how you feel after jumping in a pool and then getting out).
It’s important to remember how different cows and calves are, just because you crank fans on in your cow barn, doesn’t mean you should be doing that in your calf barn.
Just because the high for the day is 70F, doesn’t mean it will be 70F all day. It might only get that warm for 1-2 hours.
Calf jackets add about 10F to an environment, deep, long cut, straw bedding will add a couple degrees to keep them warmer.
Lastly, we understand that this isn’t a perfect science, and that you probably can’t go out every morning and take jackets off, and then put them back on at night. All we aim to do with this article is to help you make a more informed decision when it comes to managing your calves in times of variable weather, because it’s when many people, us included, have more problems. Calves thrive on consistency, so whatever we can practically do for them to buffer out some of those variations will only help them out.
We won’t be ditching the jackets for a couple weeks yet, how about you?
If you aren’t sure, send us a message and we can help you get a protocol in place for your calf jackets.