A good hay test is valuable in designing an appropriate, cost-effective supplementation plan for winter feeding. Hay quality cannot be judged based on looks or if it was fertilized or not. Often, some of the best-looking hay will test out to be some of the lowest quality.
Several factors influence hay quality including species, variety, maturity, temperature, nitrogen fertilizer, weather conditions during the hay-making process and moisture content of hay when it is baled.
Each cutting of hay should be sampled separately because they can vary greatly in quality depending on growing conditions. It works well to wait until the fall to sample all cuttings at the same time. Use a hay probe to collect samples from about 10% of the bales from each cutting. Mix these samples together to create a composite for each cutting. If you don’t have a hay probe, check with your local county extension office, as they may have one you can borrow. Unless the hay is extremely low quality, a good push-type hay probe is generally faster and easier to use than a drill-type probe. For round bales, sample from the rounded side.
A good hay test should provide values for the major analytical fractions. Values should always be listed on a dry matter basis. Below is an example of these fractions and values for one sample of bermudagrass hay.
- Adjusted crude protein: 11.5%
- Neutral detergent fiber (NDF): 64.2%
- Starch: 2.9%
- Water-soluble carbohydrates: 6.2%
- Fatty acids: 0.61%
- Ash: 6.75%
- Residual organic matter (calculated by subtracting the above values from 100): 7.84%
The amount of each of these fractions and their digestibility will impact the total digestible nutrients (TDN) content of the hay. Some fractions are pretty consistent in digestibility, however, others, especially NDF digestibility, can vary greatly from sample to sample. Consequently, it is critical to get an estimate of NDF digestibility.
Unfortunately, not all forage testing labs are the same, and many don’t provide the best information to get a meaningful estimate of hay quality. Before sending a sample to a lab, it is best to visit with a ruminant nutritionist to determine which lab to send the sample to and which tests are most appropriate for your sample.
