Drought-stricken pastures have very little grass this fall, which means cattle and other animals could graze too much on potentially poisonous substances, such as acorns, says LSU AgCenter veterinarian Steve Nicholson.

“The acorn crop is good in some areas of the state, so there is the potential for cattle to eat too many,” Nicholson says, explaining acorns contain gallotannins, which damage the digestive tract, liver and kidneys of livestock that eat large amounts of acorns. “It is really a case of too much of a good thing. Some cattle seem to develop a taste for fresh acorns and will eat large amounts of them.”

When acorns provide 40 percent to 50 percent or more of the diet for a week or so, the animal is likely to develop oak poisoning, Nicholson says.

“The number of animals in a group affected may range from 10 percent to more than 50 percent, and most will die,” the LSU Ag Center veterinarian says.

Signs of acorn poisoning include loss of appetite, weight loss, constipation followed by a fluid stool containing blood and mucus, a dirty muzzle and frequent voiding of clear urine. Kidney failure already has occurred by the time cattle show these signs, according to Nicholson.

The veterinarian says other signs of oak poisoning may be an accumulation of fluid beneath the skin that may appear in various locations and black or red loose stool, which indicates digested blood or fresh hemorrhage. Abortions also may occur along with these signs of illness, he says.

Prevention of acorn poisoning is difficult if the animals cannot be moved to a safer pasture, Nicholson says. “Cattle really like green acorns.” Feeding 4 pounds of cubed feed per day containing 10 percent to 15 percent calcium hydroxide is said to be effective but is not always practical. Prevention of acorn poisoning is best accomplished by removing cattle from pastures where acorns are abundant now, since the acorns may not be as attractive to cattle after a few weeks.”