How to balance a ration for mature does

Below is an example of how you might balance a ration for mature does using orchardgrass hay.

Requirements for a 110 lb doe in the last four weeks of pregnancy.

Daily DM (lb.)* Crude Protein (lb.) TDN (lb.) Calcium (lb.) Phosphorus (lb.)
3.5 .38 2.3 .01 .01
 * DM stands for dry matter      

Nutrient content of Orchardgrass hay (sun cured, early bloom)

89% dry matter

12 % crude protein

60 % TDN

.27% calcium

.34% phosphorus

Step 1 Calculate the amount of hay dry matter needed to meet the TDN requirement.
Divide lbs of TDN required by the amount in the hay
2.3÷ .60 = 3.8 lbs of hay dry matter

Step 2 Calculate the amount of crude protein provided by the hay dry matter.
Multiply the percent of protein in the hay by the number of pounds of hay dry matter.
3.8 X .12 = .456 pounds of crude protein

Step 3 Compare the crude protein requirement of the ewe to the amount provided by the hay.
The hay will provide more protein than the doe requires. Therefore the doe needs no further supplement to the hay to meet her nutritional needs. (This is one example where balancing a ration can help you save money. If you have any hay in the barn that was harvested at a later maturity or was weather damaged, you can feed this to your does and save the better quality hay for the younger animals which have a higher requirement for protein.)

Step 4 Compare the nutrient requirements for calcium and phosphorus to what the doe will receive from the hay.
Multiply the percent of the nutrient in the hay by the amount of the hay dry matter fed.
3.8 X .0027 = .01 pound calcium
3.8 X .0034 = .01 pound phosphorus

Step 5 Compare the amounts of calcium and phosphorus provided in the ration to the amounts required by the animal.
The hay provides .01 pound of phosphorus and .01 pound of calcium. The doe requires .01 pound of phosphorus and .01 pound of calcium. Therefore, the hay meets the requirement for phosphorus and calcium.

Step 6 Compare the amount of hay being fed to the amount of dry matter required each day.
The hay dry matter needed to meet the TDN requirement is slightly above the required DM requirement. You can meet the needs for the doe by over feeding the hay, however you will probably want to feed slightly less hay and add about one half pound of grain to increase the energy in the ration. Although the hay could meet the nutritional needs, you will want to keep in mind that the doe will need added energy if the temperature is below freezing. Also, don’t forget that if you feed 3.8 pounds of dry matter, your actual amount you feed goes up to 4.3 pounds. (3.8 lbs dry matter ÷ .89 (89 % dry matter) = 4.3 lbs as fed).