Why Test Forage Quality?

For nearly four decades, scientists have been refining their ability to test forage quality. This has been done to improve animal nutrition and, consequently, enhance animal production. Analytical procedures that previously required a week or more to complete can now be completed in under 10 minutes and with greater accuracy than before. As the ability to analyze forages has improved, the understanding of how to utilize test results to enhance animal efficiency and performance has also improved. Unfortunately, though, forage quality testing is a valuable management tool that many livestock producers still do not utilize. For a more in-depth explanation of the forage sampling and analysis process, look at the Penn State article on Forage Quality Testing: Why, How, and Where.

Greater net profit is the bottom line for why livestock producers need to know the quality of the forages they are feeding. If forages are not tested, animals may underperform due to a lack of awareness about nutrient deficiencies in their diet. Conversely, forage quality may be higher than is necessary for a particular animal group, resulting in excess nutrients passing through the animals and being wasted. The forage may be better suited for a different animal group or in a different combination of feedstuffs for a mixed ration. Matching forages to animal groups and understanding the need for supplementation can only be achieved effectively when forage testing is used to inform management decisions.

Guessing that forage crude protein is greater than what it actually is will likely lead to insufficient supplemental protein being added to the ration. It will save on feed costs, but unfortunately, the cows will be "short-changed" on CP and likely fall short of their production goals. For lactating dairy cows, milk production is negatively impacted, especially during early lactation. For brood livestock, saving the best hay for the last trimester of pregnancy and the following period of heaviest milking will better accommodate recovery for the dam and benefit any suckling offspring.

Estimating fiber and mineral content will also have a significant economic impact. For example, the neutral detergent fiber (NDF) content of forages helps determine how much of the forage an animal can consume. Guessing too high or too low can have tremendous implications on intake, animal performance, and health. Knowing the quality of the forage being fed to animals not only saves or makes more money, but it also allows managers to fine-tune diets to meet production and efficiency goals for milk production or weight gain relative to feed consumption. For more details on feed analysis and phase feeding for animal groups, read Determining Forage Quality: Understanding Feed Analysis.

Knowing the quality of forages when selling or buying them has also proven to be economically smart. Grass hay removes approximately 50 pounds of nitrogen, 50 pounds of potassium, and 15 pounds of phosphorus per ton of dry matter harvested. Based on 2024 fertilizer prices, each ton of hay contains approximately $75 in fertilizer. If manure or legumes are used to supply nitrogen to the crop, input prices can be reduced, but all management costs should be reflected in the selling price. Forage quality testing will provide accurate ash, or mineral content, to make precise estimates of nutrients leaving the operation.

Forages, such as dry hay, can be sampled when they are harvested. Sampling at harvest allows them to be sampled by field or lot and sorted in the barn according to quality for the purpose of understanding how much or how little supplement may be needed during winter feeding. Forages should be sampled closer to feeding time. It is essential that the ensiling process is complete before taking the sample. Waiting an adequate period will allow for a more accurate measure of digestible fiber and starch, as well as any hazardous acids, in the feedstuffs being fed to livestock. However, you want to leave enough lead time between sampling and feeding the forage to receive test results and adjust rations as needed.

The bottom line is that investing in a forage quality analysis is a cost-effective way to make informed decisions that will benefit both animal health and the economic well-being of a livestock operation.