Cattle and Horse Salivation Could Be Black Patch Disease
If you have cattle or horses that are salivating excessively, the cause could be in what they're eating, particularly red clover pasture or hay, and possibly white clover, according to Purdue Extension agronomist and forage crop specialist, Keith Johnson.
"The slobbering is associated with black patch disease caused by Rhizoctonia leguminicola," Johnson says. "Conditions were right for its development this year, with the rain and high humidity."
However, Johnson points out that storing clover hay may help solve the problem. "The compound does decrease in red clover hay while in storage," Johnson says. "One study sites a decrease after 10 months of storage from 50 to 100 parts per million to 7 parts per million."
Johnson cites Peter Cheeke's book, "Natural Toxicants in Feeds, Forages, and Poisonous Plants," in which the biological effects associated with black patch disease in cattle include excessive salivation, eye discharge, bloat, frequent urination, watery diarrhea, reduced milk production, weight loss and abortion. "Serious symptoms such as reduced milk production and abortion would be associated with only extreme cases of the disease that would be brought on by a diet very high in the compound," Johnson says.
Other symptoms of a severe case can include increased pancreatic flow, bile flow, and gastric acidity, decreased heart rate, cardiac output, respiration rate, body temperature, and metabolic rate.
Johnson says if cattle and horse owners observe mild slobbering symptoms or notice other mild signs, it doesn't have to mean removing clover from their animals' diets.
"If you truly don't enjoy your horses because of the slobbers, maybe so," he says. "Keep in mind, though, that you may not see slobbers to this extent for many years. I'm not convinced that one reduces use of clover because of all the nasty things described in Cheeke's book unless you have seen these symptoms.
"You need to balance the positives and negatives for the use of red and white clover in your pasture."
Johnson says using clover is positive in that it improves forage quality, provides summer pasture, and reduces the need for nitrogen applications in the pasture grass around it.
Whether the positives make coping with excessive salivation worthwhile, is for horse and cattle owners to judge, he says. "Maybe alfalfa, where adapted, should be the legume of choice when seeding your next hay and pasture fields.