Originally published: http://www.motherearthnews.com//homesteading-and-livestock/determining-livestock-your-field-will-support-zbcz1403.aspx
Long lush forage after resting in August and September. This is going into Autumn in style!
You start with a couple head of livestock because you know that one would be lonely, or you brought home a momma and baby. Then magically your herd became larger, or you added different animals. Now you are looking at your field and wondering “How many can I really manage?” Perhaps you have not even ventured into animal husbandry but are preparing and still you need to know, “How many head can my field carry?”
Googling around you come across terms like AUM (animal unit months), AUE (animal unit equivalent). Looking at the tables and worksheets you see fill in the blanks, division symbols, and it all becomes fuzzy.
The following is a very unofficial way we at SteelMeadow figure how many animals our fields can carry and for how long. We started by doing two things 1: we attending a three-day grazing school sponsored by the state’s natural resource offices and 2: we use management intensive grazing.
I would like to think that most states offer grazing schools through university extensions or state offices. Go, do, learn. It will be the best investment of your time. In Missouri we learned about stocking rates/densities, how to build watering systems, how to fence and assorted other topics such as field planting and soils.
Using management intensive grazing, the herd is given only as much field as we allow and we move them every day or every other day. Imagine being given a whole pizza; you look at it and pick off your favorite toppings, then you poke about for your next favorite, then it becomes unappetizing and you don’t want it any more. Now if you were offered just a thin slice of pizza with all the toppings, you would be more inclined to eat the whole slice, even those toppings you might not like but darn it, you are hungry so you eat it. Our cows and goats do the same thing.
The more you can divide up your property into small grazing areas, the more efficient it will become- plain and simple. This does two things – the animals eat better/more thoroughly and the section will be given a much needed rest period. There are conferences, workshops, and many books devoted to this topic alone and are very worthwhile to the beginner.
When considering stocking rates, you need to know 1: how much your animal weighs, 2: how tall your grass is and 3: how large your grazing area is. Like I said, this is just a ballpark method for figuring and is not official. I prefer to use the 3 percent rule: my animal will eat 3% of its weight every day. If the majority of your grazing animals are young and growing, use 4 percent.
How much do my grazing animals weigh?
This will help you identify how much one animal will eat and multiply it by the total number you have:
750 lb cow x 3 percent = 22.5 lbs a day (yes, we have small cows)
6 cows x 22.5 lbs= 135 lbs a day
Now, how much grass* is in that field?
Each inch of grass is worth 300 lbs of food per acre. If it is a thick, lush stand you can say 400 lbs per inch per acre and if it is rather sorry, then 200 lbs per inch per acre.
(*For the sake of argument, let’s say your field is a mix of grasses in moderate condition.)
How tall is that grass?
You must measure and you have to allow for the “take half/leave half” motto. Your field is 12” deep? Then figure your herd should eat 6”:
6” x 300 lbs per inch per acre = 1800 lbs of food in a one acre section.
How long will my one acre feed my herd?
Your herd of 6 small cows needs 135 lbs of food each day, so that one acre should supply them for 13 days.
Here is our actual animal load:
10 cows at 750lbs x 3%= 225 lbs required for the cattle each day
20 goats at 125 lbs x 3%= 75 lbs required for the goats each day
300 lbs a day total needed and a grazing paddock with forage 12” deep will last them 6 days per acre (which is exactly what we do).
Our two grazing fields, 12.5 acres and 9 acres, are subdivided with electrified twine. The 12.5 acre field is in 16 paddocks, the 9 acres in 9 paddocks. We know, by doing the above figures, how long to leave them in each paddock. According the The Missouri Forage and Grassland Council, “Continuous grazing without divisions will net 30% efficiency in available forage. Divide it into 4ths and you will increase it to 35%. Make it 8 divisions and you have bumped it up to 50%. 12 divisions will yield a 65% efficiency and 24 divisions in that same field will bring you 75% (or greater) efficiency.” It is the whole pizza vs. a thin slice of pizza…
Our 9 acre field, subdivided. Alley to the pond follows the terrace made on the sloping hill.
By slicing up your grazing pizza, you let your subdivided sections rest and regrow. Ideally you can let it rest for 3-6 weeks but this depends on rain, fertility of the field, and various other forces.
You move animals faster in times of rapid growth and move them slower during times of slow or no growth. It is counter-intuitive but it is the truth. In the spring/summer we move the herd quickly, leaving more than half and in times of drought and late Fall they take it down to about 4”.
This alley shows constant use, but look at the paddock where the herd is-green grass in the heat of August!
During the year, the 9 acres is grazed three times: May into June, August into September, Mid October into December. The 12.5 acres is grazed mid-December into May and mid-June into July. This larger field is allowed to totally regrow from mid-July till December for “stockpiled forage.” This long, long grass will feed the herd from December into May, allowing us to give them one section a week. Yup- each section is grazed only 2 or 3 times a year. No over-grazing, manure and urine go where you want it (free fertilizer) and your fields last much longer.
Keeping water available to the herd no matter what paddock they are in is crucial. Some graziers have portable waterers, some centralized ponds or tanks. We have alleys that connect paddocks to water, having the herd walk no more than ¼ mile to the tank or pond.
Management intensive grazing is cost effective. It makes the most of what you have and saves you money in the long run. It improves the soil, you get free fertilizer and your animals are healthier from a broad diet. The above formulas are also helpful when figuring out how much hay to buy to supplement your feeding. If you know how much your herd requires a day how much the hay weighs you have then realized how many bales you need for x-number of days.
Now for some reason I am craving a slice of pizza….