Part of planning for the grazing season is getting a good handle on how much forage you’ll need for your livestock. This, along with your forage estimate, tells you how many animals you can sustainably raise. It also helps you plan paddock sizes, when to move animals and what your rotation will look like over the course of the growing season.
In general, an animal eats between 2 and 3% of its body weight each day. You can do the math for the class of animal you’re raising, or you can use the Animal Unit Equivalent (AUE) tables below.
An Animal Unit Equivalent is a term used mostly in the U.S. West where the concept was first used as a US Forest Service tool for figuring out how many sheep or goats could be substituted for grazing cattle (5/cow). The ratio is based on how much one 1,000 pound cow and her calf will eat. Land management agencies write grazing permits based on Animal Unit Months, or the amount that 1,000 cow and her calf will eat in a month. Then, as you see in the tables below, every other animal is a ratio of that base number.
If all that is confusing, don’t worry. This chart will tell you how much an animal eats per day, month and year. Figures are based on a daily air-dry matter intake of 2.2 to 3.0% of body weight, depending on the nutritional demands for the type and class of livestock and wildlife. Wildlife values are based on the nutritional needs of average-sized breeding females. (Click here to download this chart courtesy of the Natural Resources Conservation Service.)
From there, it’s fairly simple to do the math. Just multiple what the animal eats by the number of animals you have and you’re on your way. If you’d like to see how that can be converted into paddock sizes with rest and recovery periods figured in, check back next week where Troy Bishopp and John Suscovich will lay it out for you and provide you the worksheets to make it easy.
Going Deeper
In this On Pasture article, Krista Ehlert factors in forage quality and it’s effect on how much an animal can eat. She also provides a link to an online calculator from South Dakota State University. You can use it to figure numbers of animals per acre based on different classes of cattle and on how long you would like them to stay in one pasture. It’s a nice way to be able to fiddle around with paddock sizes and animal numbers without actually building fences or buying the animals. Do check it out below!
On Pasture Forage/Feed Calculator
While it’s not as flexible as the SDSU calculator, I also put together a simple spreadsheet calculator to help readers figure animal needs. You can find it below:
A Simple Spreadsheet For Figuring Forage Availability, Winter Feed Needs and More
I hope that gets you on the path for developing your 2022 grazing season plan. And remember to check back next week when Troy Bishopp and John Suscovich take us on a walk through of figuring animal needs, paddock sizes and how to put it all together as a plan that even includes much needed time away from the farm.
