Hay Testing for Efficient Winter Feeding

Christine Gelley, OSU Extension Educator, Agriculture and Natural Resources, Noble County

As this year comes to an end, most Ohio graziers are probably feeding a good portion of hay as a part of their animals’ daily ration. Even if there is a supply of stockpiled forage available, we tend to make hay available just in case they need a little extra. It is likely that grain is also part of that daily ration. Well, how do you know how much hay, grain, and pasture they need? No one wants to leave their animals hungry. In addition, we do not want to waste time or money with unnecessary feeding. Figuring out the balance can seem like a guessing game, but the place to start is with a hay test.

Testing the hay you are feeding is well worth the price of sample analysis. Collecting a sample is not complicated and typically results are available from the lab within two weeks. You can acquire the tools and kits on your own to submit samples, or you can find them at most county Extension offices and often from Soil and Water Conservation Districts. Ag co-ops usually offer sample analysis services as well. Whoever you chose to go through, be sure to select the analysis package that will give you the detailed results you desire. The package that costs the least will probably still leave you guessing. My typical suggestion is to select a test that will give you values for moisture, crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), total digestible nutrients (TDN), and Relative Feed Value (RFV). Once you receive the results of your analysis, the challenge of interpreting the values arises. How do you know what values are good or bad?

Your hay test results will list values on a dry matter (DM) and an as-fed basis. Nutrients will appear to be higher for DM basis, because all the remaining water (% moisture) in the hay has been factored out. For CP, values of 8% or greater are desired. For ADF, lower is better. Increased ADF values equal decreased digestibility. Neutral detergent fiber is the amount of total fiber in the sample, which is typically above 60% for grasses and above 45% for legumes. As NDF increases, animal intake generally decreases. For TDN and RFV, the greater the values, the more desirable the forage. These values are useful for comparing your forage to other feeds available on the market. Once you have these values compiled you can start formulating rations based on nutritional values of the hay.

First, consider the needs of your animal. Stage of life, current weight, desired weight, and environmental conditions are all important factors. For the sake of an example, let’s assume we are developing a ration for a growing Angus heifer. Currently, she weighs about 800 lbs. and we want her to gain about 200 lbs. by the end of March. Ideally, we would like her to gain about 2 lbs./day. Now, let’s take a look at a hay test example and assume it is for our hay (see Table 1.1).

Table 1.1:

Sample #: Field 1
Sample Type Fescue Hay
Moisture (%) 15.91
Dry Matter (%) 84.09
Crude Protein (DM%) 12.53
Fiber ADF (DM%) 37.79
Fiber NDF (DM%) 72.03
Total Digestible Nutrients 59
Relative Feed Value 77

According to the information from our hay sample and the recommendations from the National Research Council (NRC) for beef cows, we could expect this animal to eat about 21 lbs. of hay daily. This hay should be adequate for meeting the heifer’s energy needs for maintenance, but it will not meet her demands to gain the weight we want. We need to supplement with some high energy, high protein grain to reach our desired average daily gain (ADG).

Soybean meal has an average of about 44% CP. Supplementing 2 lbs. of soybean meal (a pelleted form will increase animal intake) and 6.5 lb. of whole shell corn will meet our ADG of 2 lb. Corn is about 9% CP, which is lower than the CP content of our hay, but TDN is greater at 88% and provides more calories per pound. Supplementing corn is beneficial because it provides more energy per pound of feed, which means more gain per day.

Our hay test did not tell us how many calories our hay would provide per pound, but we can reference NRC again for these values. Our 800 lb. heifer needs 6.41 Mcal/day to maintain body weight and she needs an additional 5.11 Mcal/day to gain 2 lb./day. The average net energy for gain (NEg) in Mcal/lb. for fescue hay is 0.32, soybean meal is 0.59, and whole shell corn is 0.61. If we feed 21 lb. of hay, 2 lb. of soybean meal, and 6 lb. of corn, we will meet our goal (see Table 1.2).

Table 1.2:

Feed Type & Quantity Energy Provided
Energy Required for Maintenance Mcal/day Energy Required for Gain
Fescue Hay:
21 lb.
6.72 6.41 5.11
Soybean Meal:
2 lb.
Whole Shell Corn:
6 lb.
Total Energy Provided: 11.56
Total Energy Needed: 11.52* *6.41+5.11

This was just one example of how a hay test can help with the development of livestock rations. Recommendations will vary depending on types of hay, time of year, animal species, stage of life, and production goals. With so much possible variation, every little bit of knowledge we can secure is helpful for developing production goals and expectations.

Hay tests may not reveal ideal results and they can vary drastically between cuttings. That is the reality of attempting to manage nature. We can rarely do anything under ideal circumstances, but we do the best we can. As you look ahead to the next growing season and putting up hay once again, do everything you can to efficiently improve forage quality and nutritive value of your stored resources. The better the nutritive value of your forage, the less you will need to supplement and the more money you can keep in your pocket. Testing and formulating rations takes some effort, but once it becomes routine it will come with greater ease.

With that, I will leave you with a quote from Jim Rohn, “Success is neither magical nor mysterious. Success is the natural consequence of consistently applying the basic fundamentals.”

Happy New Year! My best wishes to you and yours for 2018!

Jurgens, Marshall, et al. “Feedstuffs and Formulations.” Animal Feeding and Nutrition, 11th ed., Kendall Hunt Publishing Company, 2012, pp. 87–116.