November 2017
Farm & Field

Rains May Result in Lower Quality Hay

Know how to assess the feed value of your cut forage.

The good news is that Alabama had ample rain this summer. The bad news is that these rains may result in lower-quality hay this winter. In many cases, rains delayed cutting, damaged already-cut hay in the field or forced some to bale hay at improper moisture levels. If you harvested or bought rain-damaged hay this year, the questions now are, "How bad is the damage?" and "What is its feed value?"

Try to avoid feeding low-quality hay to calves, lactating cows and cows during late pregnancy. When in doubt, always provide a nutritional supplement providing protein and/or energy to help bridge any nutritional gaps.


How Over Maturity Affects Quality

Weather delays can sometimes set back hay harvests by weeks. This delay results in over-mature forages. While species variations exist, in general as a plant matures, it converts from a vegetative (leafy) state into a reproductive (stemmy) state. When a plant is in the reproductive state, its nutritional resources are focused on producing reproductive structures (flowers, stem, seeds, etc.) instead of leaves. Nutritional quality decreases due to an increase in indigestible fiber (stem) and decreased nutrient content (leaves). Indicators such as stem size and softness as well as the presence of seed heads or flowers can help to gauge forage maturity. Hay containing excessive numbers of mature seed heads will be relatively low in nutritional quality. Desirable hay contains an abundance of leaves and low amounts of seed heads and large stems.


How Rain on Cut Forages Affects Quality

Damage occurs through a variety of different avenues. First, rain will cause leaching of nutrients from the cut forages. Second, rain contributes to leaf shatter. And last, wet forages result in increased drying times.

Rain causes highly soluble cell contents to leach out of the plant. Unfortunately, these highly soluble components are highly digestible by the animal and include soluble carbohydrates and nitrogen as well as minerals and vitamins. Loss of soluble carbohydrates results in a reduction in total digestible nutrients. Because soluble carbohydrates are lost during leaching, structural fibers become more concentrated in the forage. These fibers are largely indigestible and thus reduce the overall digestibility of the forage. Hay digestibility may decline from 6 percent to as much as 40 percent.

Leaf loss also affects quality. The drier the hay, the more susceptible it is to leaf shatter. The force of the rain itself can cause leaves to shatter or fall off, but a more likely cause of leaf loss is due to increased handling caused by rain. Hay containing less than 30 percent moisture will be very prone to leaf loss when raked or tedded. This is especially true of legumes (alfalfa, clover, peanut, etc.).

Obviously, forages that have been rained upon require longer drying times. This can negatively affect quality by prolonging respiration. Respiration is a natural process that results in the breakdown of carbohydrates within the plant by enzymes found in the plant. This process occurs whether the hay has been rained upon or not. Respiration losses will occur until the forage moisture drops to below 30 percent. These losses are normally about 3-4 percent of dry matter. However, when the forage has been wetted by rain, this process is prolonged or begins again (when hay was previously below 30-percent moisture).



Weather delays can sometimes set back hay harvests by weeks. This delay results in over-mature forages.

How Baling at Improper Moisture Levels Affects Quality

Hay baled at 22 percent moisture or above will usually develop mold and undergo excessive heating. Molds on hay will certainly reduce overall palatability and nutritional content, but some varieties can produce toxic compounds. Extreme caution is advised when feeding moldy hay. Under normal conditions, the low-moisture content within properly cured hay will inhibit microbial growth and thus spoilage. However, wet hay (above 22 percent moisture) contains enough moisture to allow growth of anaerobic bacteria. Given proper conditions, enough heat (over 200 degrees) can build up to cause spontaneous combustion and hay fires. Even if hay does not ignite, excessive heat will damage proteins and reduce overall digestibility and palatability.


What do I do if I Have Rain-damaged Hay?

The first thing I recommend is to have all of your hay chemically analyzed. This will allow you to access nutritional quality and determine which groups of animals should (or should not) receive the hay. In the absence of a forage analysis, assume the quality is poor and feed to mature cattle (bulls and cows in the first half of pregnancy). Try to avoid feeding low-quality hay to calves, lactating cows and cows during late pregnancy. When in doubt, always provide a nutritional supplement providing protein and/or energy to help bridge any nutritional gaps.


What Types of Supplements Are Out There?

Nutritional supplements come in all shapes and sizes, and range from commercially produced tubs, blocks, cubes or pellets to natural feedstuffs known to be relatively high in protein or energy such as soybean meal or corn. Choosing which type is best for your operation will vary according to individual circumstances. In many cases, a variety of supplement products will best meet cattle’s needs.

SWEETLIX offers a wide variety of protein and mineral/vitamin supplements in many different forms to help cattle producers manage for deficiencies in hay supplies. If you have concerns about the quality of your hay and don’t have a forage analysis to confirm quality, it is best to assume the worst and at least provide protein supplementation to help rumen microbes to more efficiently digest stemmy forages. Self-fed, SWEETLIX EnProAl Poured Tubs offer convenient, waste-free, protein supplementation in a variety of formulas. Just choose the product that best matches your needs.


In summary, available hay may be of lower quality this winter due to a rainy summer. When feeding low-quality hay, nutritional supplements are necessary to maintain reproductive and growth performance. Protein supplements pay for themselves in added production when used properly in these situations.


For more information about the SWEETLIX line of protein supplement products for cattle and information to help you decide how they fit in your management situation, contact your local Quality Co-op representative or visit


Jackie Nix is an animal nutritionist with Ridley Block Operations ( You can contact her at This email address is being protected from spambots. You need JavaScript enabled to view it. or 1-800-325-1486 for questions or to learn more about SWEETLIX mineral and protein supplements for cattle, goats, horses, sheep and wildlife. References available upon request.