When forage is low, cattle may seek out acorns. Acorns have the potential to cause problems for livestock. Livestock consuming small amounts of acorns typically goes unnoticed and does not cause any problems. When heavy crops of acorns are present, producers should monitor the herd as a precaution for acorn poisoning.
There are 39 species and many varieties of oak in Texas. They range from shrubs about 3 feet tall to very large trees. The leaves, usually deciduous and stemmed, are alternate, and with or without toothed margins or deep lobes. The fruit is one seeded, enclosed in a shell forming a nut or acorn, and is seated in a cup that envelopes the whole nut or covers only its base.
Acorns contain a substance called gallotannin that in rumen animals such as cattle, sheep, and goats to name a few, can be toxic. Gallotannin metabolizes into gallic acid and tannic acid. Tannic acids may cause ulcerations of the mouth, esophagus, and gastrointestinal tract. Tannic acid can especially be toxic to the kidney functions. Green acorns early in the season tend to be more of a problem.
The early stages of acorn poisoning include constipation followed by a decrease in appetite. Continued exposure to acorns in cattle with symptoms of acorn poisoning include diarrhea, constipation with blood; rough hair coat; abdominal pain; frequent urination, then no urination. Some cows will have subcutaneous edema between the rear legs above the udder. Many have a bloody froth from the nose after they have been handled.
What to do if you suspect acorn poisoning in your herd? Contact your local veterinarian right away. Acorn poisoning usually occurs within eight to 14 days of the livestock consuming large quantities of acorns. The amount of tolerance for each animal depends on the protein content of the diet. The higher the protein content is in the diet the more the animal can tolerate without having poisoning symptoms.
Examine cattle herds regularly in fall and winter months for signs of acorn poisoning. If you have pastures with heavy oak tree presence, it may be necessary to wait to graze these pastures later in the season when acorns have aged and begin to turn brown. There are other plants and plant parts that may be toxic to livestock at some stage of development. Toxicity will vary from plant to plant. Toxicity will also vary according to how much the animal consumes. Adequate forage, hay and supplementation in the animal's diet can prevent some toxicity issues to certain plants and plant parts. If the animal has plenty to eat many times they will not consume the toxic plant or plant parts anyway.
Information on acorn poisoning came from the Texas A&M AgriLife Extension Service publication titled Fall and Winter Health Problems in Cow-Calf Herds by Dr. Floron C. Faries, Jr. This information is to educate and inform of this potential problem in livestock.
Educational programs of the Texas A&M AgriLife Extension Service are open to all people without regard to race, color, religion, sex, national origin, age, disability, genetic information or veteran status. The Texas A&M University System, U.S. Department of Agriculture, and the County Commissioners Courts of Texas Cooperating.