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Fall Acorn Crops Threaten Cattle
MISSISSIPPI STATE -- Heavy acorn crops may delight wildlife enthusiasts, but cattle producers recognize the deadly threat to their animals pastured with large numbers of oak trees.
Dr. Richard Hopper, extension veterinarian at Mississippi State University, said it is common for cattle to eat acorns, but few are poisoned by them in the state. Most happen when acorns are abundant and pastures offer little forage.
"Many researchers believe the toxic element in acorns to be tannins," Hopper said. "Tannins are found not just in acorns, but in oak buds and leaves at certain times."
Acorn poisoning upsets the digestive system. The target organ is the kidney, which swells considerably and loses its ability to concentrate urine. Affected cattle urinate frequently and have a dark diarrhea.
"Cattle with serious acorn poisoning require pretty intensive care to survive," Hopper said. "If the condition is advanced, recovery is rare."
Blair McKinley, MSU extension cattle specialist, said most cows can eat a few acorns or oak buds without being poisoned. It's when they eat large amounts that a problem occurs.
"Acorns are bitter, but some cattle develop a taste for them," McKinley said. "If they like their taste, cattle will go back to acorns even if hay is provided."
Giving hay prevents many cattle from foraging for acorns, but the best solution is to move the cattle away from oak trees. Sometimes trees can be fenced off, and in other cases, the acorns can be raked and removed from the field.
"Whenever anyone suspects a plant poisoning of any type, the first thing to do is to get the cattle away from the possible source," Hopper said.
Call a veterinarian, as many cases can be treated with prescription drugs, fluids, digestive aids and purgatives.
If cattle cannot be kept from oak trees and acorns, producers can take action to prevent poisonings. Feed cattle a 10 percent ration of calcium hydroxide, Hopper said.
Acorn poisoning is not a large-scale problem in the state, Hopper said. Isolated cases do occur, but experienced cattle producers rarely have problems with acorn poisonings.