November 2013 Issue |
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IN THIS ISSUE: |
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• Subscribe to Meat Goat Mania • Email Us • Onion Creek Ranch • Bending Tree Ranch • OCR Health & Management Articles • MGM Archive |
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PRUSSIC ACID (CYANIDE) POISONING Prussic acid toxicity, also known as cyanide poisoning, takes place in certain plants and grasses that have been stressed by drought and frost. This toxin kills goats within about 15 minutes -- far quicker than the producer can normally obtain veterinary assistance. Usually the goat producer's first knowledge of a problem is dead goats. Therefore, prevention is the key to avoiding prussic acid poisoning. Wilted, frosted, or drought-stricken plants and grasses release hydrocyanic acid that inhibits oxygen utilization by the cells of the goat's body and death occurs from asphyxiation. In simplified terms, oxygen makes it to the cells but prussic acid prevents oxygen from separating from hemoglobin so that cells can utilize it. Blood remains bright red throughout the body, including normally brown-colored blood returning from cells to the heart for re-oxygenation. The goat dies ofasphyxiation. Ruminants are more susceptible to cyanide poisoning than non-ruminants because the rumen releases greater amounts of hydrocyanic acid. Soils with high levels of nitrogen and low levels of phosphorus and potassium increase the possibility of prussic acid toxicity in the plants and grasses grown in them. Some of the many plants and grasses that, when eaten by goats, can cause prussic acid toxicity under specific environmental conditions include sorghum grasses (especially Johnson grass), sudangrasses, hydrangeas, the wilted leaves of wild cherry trees, Indiangrass, chokecherry, peach, and white clover. Several of these crops are used as hay and are safe to feed because prussic acid disappears during the hay curing process. The goat producer needs to learn about grasses and plants on his property and the soils in which they grow. Symptoms are generalized and include frothing at the mouth, slobbering, increased respiratory rate, mouth breathing, rapid but weak heart rate, and muscle twitching. Mucous membranes are bright red, indicating the lack of oxygen transfer throughout the body that is necessary for survival at the cellular level. Death from respiratory paralysis occurs during severe convulsions. The heart continues to beat for several minutes after struggling ceases and breathing stops. Bright red blood often comes out of the nostrils and mouth. This entire process seldom takes longer than 30 to 45 minutes. It is a quick and painful death. If the goat manages to live for more than two hours following onset of these symptoms, it will likely survive. However, the death rate far exceeds the survival rate. If the goat producer is fortunate enough to obtain immediate veterinary help, the vet will usually administer an IV solution of sodium nitrite and sodium thiosulfate to "neutralize" the production of hydrocyanic acid by the plant's cells. This is not a skill that the average goat producer possesses. Some veterinarians are treating both prussic acid poisoning and nitrate poisoning with methylene blue when they are not positive of the cause of the toxicity. Treating nitrate poisoning with sodium nitrite and sodium thiosulfate will kill the goat. |
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Several things can be done to reduce the risk of goats' contracting prussic acid poisoning: 1) Feed a small amount of commercially-prepared goat feed before the goats are turned out on forage/browse/pasture. An empty rumen has a greater risk of contracting cyanide poisoning than does a rumen with food in it. Offer quality hay year around to buffer the rumen. 2) Never feed wet or moldy hay or grain to goats. This includes silage. 3) Avoid grazing drought- and freeze-stressed plants and grasses. 4) Pull goats off pastures before a freeze and wait at least seven (7) days and sometimes longer after the thaw and wilt before repopulating with goats. Some of the most toxic times, especially on the sorghums such as johnsongrass, occur after a dry period has "browned out" the forage and rain has started new growth. This new growth can be very high in the prussic acid and can cause deaths. Several weeks of growth may be necessary before the plants are safe again. Producers can send plant samples to toxicologists for analysis to determine how soon goats can be let back on the affected land. Send the sample in a sealed container (mason jar - not a baggie) so that the gas released by the plant in the jar can be analyzed. Check with the toxicologist about proper sampling and mailing procedures. 5) Regularly rotate pastures when plants and grasses are grazed down. Remove animals from drought stressed pastures when rain has started new growth. Suzanne W. Gasparotto ONION CREEK RANCH Lohn, Texas |
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Nitrate Poisoning: Hemoglobin that carries oxygen in the blood is replaced by nitrates, which cannot carry oxygen. The goat dies from lack of oxygen in its body's cells. Lack of oxygen explains the chocolate-colored blood. Prussic acid (cyanide) Poisoning: Hydrocyanic acid prevents release of oxygen in the blood; the goat dies from lack of oxygen in its cells.The blood stays red because oxygen is still in the blood. |
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