Kentucky's Fields Of Dreams Now Nightmares

The old-timers say Kentucky is horse country because of its soil. What's now growing on that soil could be the cause of a rash of late-term losses in foals, early embryonic death, pericarditis (fluid surrounding the heart), reduced growth rates in young horses, and other problems that might not yet have been recognized.

Dr. Tom Riddle, a founding partner of Rood and Riddle Equine Hospital in Lexington, was the veterinarian who first recognized the current syndromes at work in Kentucky. He and several other experts agree that "it's reasonable to assume (the cause is in) pastures, so remove horses from pastures." He said one client took that recommendation so seriously that he "plowed under" his pasture. Many others are mowing pastures very short.

These recommendations are being made because experts are looking at mycotoxins on pasture grasses as being the culprit(s) for the current situation in Kentucky and other states. Mycotoxins are produced by molds as a defense mechanism, explained Dr. Kyle Newman, a nutritional microbiologist with Venture Laboratories in Lexington. Molds don't like moisture, but they do like damaged plants such as those you find after a freeze. It is thought that the environmental shift this spring from warm weather, followed by a frost and then drought conditions were ideal for the production of mycotoxins.

Newman explained there are many different types of mycotoxins that are detrimental to animal health. It is possible that, at this stage in Kentucky, the molds might have produced the mycotoxins and died. However, the mycotoxins are still on the plants.

One of the problems with mycotoxins is that unlike some forage problems, animals don't recognize that the plants have something bad on them when they are grazing. Therefore, they don't "wise up" to the intake of mycotoxins, said Newman.

Getting rid of the mycotoxins might take something as simple as a good, steady rain, or maybe even heavy watering. Newman said processed grains are treated by washing them with water to remove mycotoxins, but, "no one knows how much water is needed" in a pasture situation. "It would be worth a shot," he said of trying to experiment on a paddock and measuring mycotoxins before and after a certain amount of water was applied. While this wouldn't be a solution to the current problem, if small paddocks could be "washed" of the mycotoxins, at least there would be some turnout areas for horses now confined to stalls or dry lots.

While the current recommendation is to cut pastures to help reduce the potential exposure to mycotoxins, Roger Allman, a pasture consultant for The Farm Clinic, said farm managers should be cautious with short pastures. He said if pastures are cut and there is no rain, then they will be very dry and that could possibly set up the scenario for the damaged, dry grass to have more mold growth, and more mycotoxins.
Dr. Jimmy Henning, an extension forage specialist at the University of Kentucky, also warned that if mycotoxins are in hay that is cut, it should be removed and used as feed for cattle or other animals. "The leaves that were present during the frost contain mycotoxin, so that cutting (of hay) should go someplace else." Dr. Steve Jackson, an equine nutrition consultant and owner of Bluegrass Equine Nutrition, said he would take first-cutting hay from Kentucky and round bale it for cattle. "Don't cut it and leave it on the field." The hay can be tested for the presence of mycotoxins and fed to horses if it is free of the problem.

The question that wasn't answered was whether grass should be removed from pastures that were cut (and possibly contain mycotoxins) before horses were turned back out to graze.

About the Author

Kimberly S. Brown

Kimberly S. Brown was the Publisher/Editor of The Horse: Your Guide To Equine Health Care from June 2008 to March 2010, and she served in various positions at Blood-Horse Publications since 1980.

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