The variable weather and the price of straw and shavings has led some horse and farm owners to look for alternative beddings. In some areas of the country, mature grass hay that sells fairly cheaply seems like a safe, inexpensive alternative. However, you need to make sure that the hay doesn't contain endophyte-infected tall fescue. In this article from the University of Kentucky you will get some good advice if you are using mature grass hay as bedding.
Due to the drought this past summer, straw is expected to be in short supply and more expensive than in recent years. A number of horse farm managers have chosen to harvest or purchase bedding from over-mature pastures rather than pay a premium for straw.
On the surface, it makes sense to use this stemmy hay for bedding. But, be cautious when using this hay for bedding pregnant mares during their last trimester. It is not uncommon for horses to eat some of their bedding, especially if it is hay, and ergovaline levels over 200 ppb (parts per billion) can cause fescue toxicity in pregnant mares.
Surveys show Central Kentucky horse pastures often contain more than 25% tall fescue. Since the stem and seed head of tall fescue contain the highest levels of the toxin ergovaline, there is a good chance that mature hay could contain toxic levels. In other areas of Kentucky and in surrounding states, tall fescue often makes up more than 50% of horse pastures.
If you are using over-mature grass hay as bedding for pregnant mares, first have it tested for ergovaline concentration at the University of Kentucky Veterinary Diagnostic Laboratory in Lexington. Work with your veterinarian or county extension agent to submit samples. Samples should be taken from the bales with a hay probe, just as you would when taking samples to test for hay quality. Make sure that the sample you submit is comprised of cores from five to 10 separate bales from each hay cutting. In most counties, the county extension agent or local farm service store can loan you a hay probe for sampling. The cost of the ergovaline test is $50 per sample. For more information, contact Cindy Gaskill, DVM, PhD, clinical veterinary toxicologist at the UKVDL at 859-257-7912.
In Central Kentucky, the UK Pasture Evaluation Program will come to your farm, sample your hay, submit it to the VDL, and send you the results with an interpretation. For more information on the Horse Pasture Evaluation Program visit http://www.uky.edu/Ag/Forage/HorseLinks.htm and click on “Testing Hay for Ergovaline.”