2017-11-02 / Opinions

Acorn toxicosis

By MICHAEL FOSTER
Agriculture and Natural Resources Agent

As we have discussed in previous articles the fall is a busy time of the year for many of our local beef producers. During this time of year producers are focused on winter grazing establishment, supplemental feeding, preparation for breeding season, and for many producers it is the time for their herds to calve. That being said, it is also the time of year when acorns are falling and covering the ground.

While falling acorns are highly desirable for whitetail hunters, they can be quite devastating for a cattle producer. The leaves and acorns of most of the oak species in the southeast are considered toxic to cattle. Oaks produce tannins – complex polyphenolic compound – which are responsible for the flavors of many nuts, coffees, wines, and tobaccos. When ingested by cattle the tannin found in acorns – gallotannin – breaks down during digestion into gallic and tannic acids. The tannic acid is known to cause ulcerations in the mouth, esophagus, and gastrointestinal (GI) tract and can lead to kidney failure. This is known as acorn toxicosis.

Acorn toxicosis is most often seen in calves but can also be seen in adult cows. In calves, tannins are often ingested through the mother’s milk. Tannins become concentrated in the milk, leaving fast gaining calves to readily ingest them. At first, the calves will become constipated, leading to a decrease in food intake. Continued exposure leads to ulceration of the GI tract. Obviously the inside of the GI tract cannot be seen without specialize equipment; however, black and watery bowel movements, that may or may not contain blood, are indicative of GI ulceration. Calves will also experience lethargy and swelling of the abdomen, chest, and legs along with dehydration – characterized by a dry, crusty muzzle and rough hair coat. In the advanced stages of toxicosis blood may drain from the nose and calves may have difficulty in urinating and defecating. If urination stops completely the kidneys have failed and death will soon follow. Symptoms in adults are similar with the addition to reduced milk production and potential birth defects.

When it comes to acorn toxicosis “an ounce of prevention is worth a pound of cure.” There are no known treatments that can counteract the effects of tannin poisoning other than removing cattle from areas with acorns and providing proper care and nutrition. Proper care and nutrition includes fluids and electrolytes to ensure that kidney function continues along with a single dose of mineral oil for constipated animals. In order to prevent infection of ulcerations in the mouth and GI tract a broad spectrum antibiotic should be administered. While these practices may help prevent death of a poisoned cow, it is not a guarantee. Once again, prevention is key.

Prevention starts by knowing the grazing areas where cattle could have access to acorns during the fall and excluding them from those areas through fencing the out or moving them to a different pasture. However, if exclusion is not possible a modified supplemental feeding program will have to be implemented. This means providing a diet that allows access to at least 0.4 pounds of hydrated lime per day to prevent the effects of toxicosis. A ration combination of corn, cottonseed or soybean meal, molasses, and hydrated lime can be fed as a supplement to prevent scavenging of acorns. It is also essential to provide winter grazing, quality hay, and/or silage to prevent foraging on oak leaves and acorns.

Acorn toxicosis can be a serious problem during years when there is a bumper crop of acorns. Currently there has not been any research to suggest the tannin levels of an acorn decrease as the winter months ensue; therefore it is critical for producers to prevent cattle from access to acorns or provide a diet that would preclude cattle from foraging on them.

For more information on acorn toxicosis contact the Wilkes County Extension office.

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