Oak Poisoning
Carol Raczykowski

An extensive series of articles appeared in the July-December 1994 issues of The Pygmy Goat WORLD on Plant Poisoning. In the September issue, Oak was one of the hazardous plants listed and we will recap the information listed there, plus new information. 

People must be cognizant of what is in their pastures - even if the animals have been in the same place for an extended period of time with no problems. The tide can change very quickly due to outside factors such as storms and downed trees.

Typically, the potential of a plant to cause problems following ingestion depends on many factors, including how much was eaten, the weight and condition of the animal, the age of the animal, the species and maturity of the plant and weather conditions. Some plants are very toxic in small amounts while others are cumulative and require a high amount of consumption over a longer period of time.

In this particular case, the downed trees made the leaves and acorns much more available to the goats. Without knowing the full details, I would assume it was the leaves and acorns, more than the bark, that created the problem.

The July '97 Plant Poisoning article describes oak as: An erect perennial woody plant, varying in size and growth habit from a scrubby bush to a tall tree. The leaves are entire, alternate, toothed or lobed and are either persistent or deciduous. The fruit is the one-seeded acorn. Over 6 species identified in North America. All oak should be considered potentially toxic. Highest toxic concentration is present in early leaf buds, immature leaves and acorns. Oak poisoning usually occurs in early spring during periods of inclement weather (blowdowns) and when animals do not have access to normal forage.

Acorn poisoning typically occurs in late fall. Animals must usually ingest large quantities of the plant material (50% of diet) for 2-4 weeks or longer before onset of clinical signs. Animals have been poisoned from drinking water that had oak leaves soaking in it. Clinical signs include initial dullness, abdominal pain, anorexia (not eating), rumen stasis (stoppage), constipation, polyuria (excessive urine), polydipsia (excessive thirst), thin/weak pulse, bloody mucous diarrhea, and chronic renal (kidney) failure. The mucous membranes are pale and there may be a watery discharge from the eyes, nose and mouth, although the muzzle is dry. Symptoms may not appear for several days after ingestion. Animals are often ill for several days or longer prior to death. They may also experience elevations in liver enzymes. Cattle are most affected, though there have been reported cases in sheep, horses, goats and chickens.

Although poisoning does occur due to green oak leaves and buds in the spring, the unripe acorns appear to be the most dangerous and outbreaks frequently occur when large quantities of green acorns have been brought down by wind. The most probable toxic culprit in the acorns and leaves is a tannic acid and a volatile oil.

The best cure for poisonous plants is prevention. This includes being aware of which plants are poisonous and eradicating them from your goats' housing and grazing areas. Unfortunately, even with prevention, poisonings will take place and you must be prepared.

If you suspect poisoning, call your veterinarian immediately for instructions. Isolate the goat and prevent further exposure to the poison while trying not to stress the animal. The most important step in therapy for any plant poisoning case is to remove any residual plant materials from the digestive tract as quickly as possible. Although goats do not vomit by nature, vomiting can be induced if the goat is conscious.

If more than two hours has passed since ingestion of the material, the stomach has probably already emptied into the intestine. In such cases, subjecting your goat to further stress through induced vomiting is unwise. Gastric lavage may also be an important procedure in suspected poisoning. A gastric tube (as large as possible) is passed to facilitate aspiration of the ingesta back out through the tube. There are also many formulas that may help neutralize the toxins but there are truly no universal antidotes. It is important to use a sufficient quantity of water to thoroughly wash out the stomach and a laxative agent (Milk of Magnesia) may be placed into the stomach to further evacuate the intestine. High colonic enemas may also be effective. As soon as the gastrointestinal tract has been emptied, you need to maintain the fluids, electrolytes and acid-base balance of your animal.

If you are unsure of the plants commonly found in your area, contact your local weed control board for help. Remember, a simple alteration in conditions could create a potentially dangerous situation. Be aware of the poisonous plants in your area and take steps to alleviate their availability to your goats.


Related Reading
Poisonous Plants & Other Toxic Substances


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