Do You Have Enough Winter Feed?
Now is the time to evaluate winter feed supplies vs. requirements and develop a plan of action. If the feed supply is inadequate additional feed must be acquired, or cattle numbers reduced (culling).
The first step is determining the number of days feed will be required. Typically this is 100 to 120 days. However, this can very greatly depending on our weather, stocking density of pastures, and the amount of stockpiled forage. Stockpiling is an excellent way to reduce stored feed requirements . . . but stockpiling all depends on the weather. For more about stockpiling visit Damon Pollard’s concise write up about stockpiling fescue (http://burke.ces.ncsu.edu/2012/07/stockpiling-forages-for-fall-and-winter-pasture/).
A quick, easy way to estimate feed requirements is on the basis of animal units. This can be done based on a mature cow equal to one unit, a mature bull equal to one and a half units, yearling cattle equal to one-half unit, and calves equal to one-fourth unit. Utilizing this method each animal unit will require approximately 25 pounds of hay or 50 pounds of corn silage, assuming average to good quality hay or silage. This also assumes less than 10% waste during feeding and storage.
For an average sized herd of 35 cows, one bull, 8 replacement heifers and 16 yearling steers with a winter feeding period of 120 days, the following is an example calculation of stored feed requirements:
35 cows x 1 animal unit = 35 animal units
1 bull x 1.5 animal unit = 1.5 animal units
8 replacement heifers x 0.5 animal unit = 4 animal units
16 yearling steers x 0.5 animal unit = 8 animal units
The herd total is 48.5 animal units.
48.5 animal units x 120 days x 25 pounds of hay per day = 145,500 pounds of hay
How many 500 pound round bales are needed?
145,500 pounds / 500 lb bales = 291 bales
You also must have a good estimate of the quantity of feed available to determine if the animals’ needs can be met. When estimating quantity of hay it is best to obtain the average weight of several bales and then multiply this times the number of bales.
Large bales stored outside uncovered sustain substantial losses during storage and feeding (http://www.afgc.org/newsletter/Winter2010.pdf – Page 4).
Remember this only a very quick estimate. To be more accurate you need to consider nutritional requirements for the size of animal and stage of reproduction or growth desired. Also, feed supply can be more accurately estimated if you have a forage analysis to determine the exact nutrient content.