Calves and Calories, Are they getting what they need in the winter?
After the new year, you might be watching your calories, but are you watching your calves calories too?
Winter calf feeding can be a challenge and can also bring many questions to mind on the best strategies and actions to take to keep your calves in the best health throughout the cooler months of the year.
One question you might have is, how do I properly feed my calves during the winter to achieve optimal ADG and health?
There are many options, but one thing that is a fact is every diet is based on calories. Calories in, calories out, it’s as simple as that! There are a couple other factors to keep in mind with this statement, we are going to go through those below.
First and foremost, we need to consider two different age groups of calves, calves that are less than 3 weeks old, and calves that are over 3 weeks old. Calves that are less than 3 weeks old are typically eating minimal starter grain, and what they are eating, they are likely using for rumen development and not actually utilizing the calories they are eating (because they literally can’t!). Calves that are over 3 weeks of age are typically eating a decent amount of starter grain AND can utilize some of that grain that they are eating for calorie intake. This also contributes to their thermal neutral zone! After a month, a calf’s lower thermal neutral zone goes from 50F to 32F. Why? Because of that rumen heater! When calves start eating solid feed, the process of digesting volatile fatty acids (butyrate, propionate, and acetate) causes the rumen to let off quite a bit of heat from the microbes working hard to digest that solid feed, and in return keeps that calf a whole lot warmer! That heat can only be created after the rumen has been properly developed to utilize volatile fatty acids from the calf eating sufficient amounts of starter. At that point a calf will also have added fat onto their body condition to help them stay warm.
So, now that we’ve discussed some quick background on who and what we are talking about, let’s go through a couple scenarios to see what this could look like for different temperatures and also different formulas of milk replacer. Today, we are just going to look at calves that are less thank 3 weeks old.
Below we are going to go through a couple examples of what you could expect for calorie needs based on temperature, age, and weight, to get an estimated ADG. There are limitations to these calculators though, which I would like to go through just for some food for thought.
They do not consider grain intake to contribute to total calories. Starter intake is very difficult to estimate in a calculator, and if a calf isn’t eating enough starter, it’s best to overestimate caloric needs than to underestimate them.
These calculators don’t consider calves wearing calf jackets, type of bedding, or nesting score. Those. of course, save calories and help keep these calves warm, but that’s something that is hard to measure too!
They don’t consider windchill. Whatever temperature number that is put into the calculator is the number it uses, if the windchill is colder, put that in.
They don’t consider their health status. An immune system that is being challenged uses SIGNIFICANTLY more calories than one that is not. That is also something that is very difficult to measure and will depend on each individual farm.
There are two ways that you can use this calculator. One way is by setting an ADG goal and figuring out how much you need to feed in order to achieve that. The second way you can use this calculator is by setting what you feed now or what you are considering feeding for winter, and using it to see what you estimated ADG would be with the amount you feed. We are going to look at it both ways!
Example 1:
Let’s say you have a 2 week old calf that weighs 90 lbs., the temperature is 32F. If you are feeding her 3 quarts twice a day (6 quarts/day) at 13.5% solids, you can expect her to gain around 0.5 lbs. per day with these specifications. The goal is to have the energy balance above -1.00.
Example 2:
Say you would like your calves to gain at least 1 lb per day in the winter. How much would you have to feed them to make that happen? You would need to increase the solids by 1% from 13.5% to 14.5% AND increase the volume by 2 quarts per day to achieve this.
Example 3:
Say it gets colder, and is 0F outside now instead of 32F. How much more would you have to feed just to cover those extra calorie needs?
In order to accomplish this and still have her gaining about 1lb per day, you would need to either increase the solids to 18.2% (which you can not do), or you can increase the volume fed to 10 quarts per day. BUT, if you don’t change anything when it gets to 0F, you can expect her to gain .01-0.4 lbs per day.
Example 4:
One common strategy for feeding calves in the winter is to add more fat, and people tend to be very successful by doing that! While adding fat works because it adds calories, it’s also important to consider the economics of doing so. A high protein high fat milk replacer can be upwards of $10-$20 per bag more, and as you can see by the calculator below, you still have to feed almost the same amount to see the same results.
As you can see from these few examples, there are a lot of options when it comes to winter feeding, but there’s one thing that’s non-negotiable: if you want your calves to gain weight and maintain health in the winter, they need more calories!
If you are interested in running your own simulations to see if your calves are getting the calories they need to perform this winter, contact us today and we can help you get started and follow us to make sure you don’t miss the next article where we dig into the economics of feeding calves in the winter!