Q) Why do some animals poison themselves? It is an unfortunate fact that animals sometimes poison themselves. In many instances this is due to consumption of artificial compounds but occasionally plants can be the causative agent. New Forest ponies sometimes succumb to acorn poisoning, domestic horses have been known to fall ill after chronic ragwort consumption and there have reports of dogs poisoning themselves on grapes. This is hard to reconcile with the observations that animals can accurately select the plants needed to rectify any problem they are experiencing. So if the ability to self-medicate is innate why would an animal select something that is bad for them? 1) Hunger: If food is scarce animals may have no option but to start foraging on toxic plants it would not normally eat. This may happen to animals who only have access to poor pastures; if there is nothing good to eat but ragwort, you will have to eat ragwort as it has at least some sustenance. This may also explain why ragwort is more toxic when it is taken systematically over a significant period of time. As a wild animal can wander, it may only have to supplement its diet with ragwort for a short period of time before it finds more nutritious food. 2) Inability to sequentially select: Several species have been seen to ingest neutralizing compounds after eating plants with high levels of plant toxins. Clay can neutralize most plant toxins whilst saponins (such as though found in Slippery Elm & Marigold) can neutralize tannins (acorn poisoning occurs due to their high tannin content). Captive animals often do not have access to neutralizing compounds and so will not be able to sequentially select. 3) Artificial context: For example it is well known that chocolate can poison dogs. This is due to its theobromine content, an alkaloid found in the coca plant that dogs cannot metabolize very well but that humans can. Chocolate also contains other ingredients, most notably sugar and flavourings such as vanilla. It may be that the additional ingredients in chocolate mask the smell and taste of the theobromine, preventing the dog from perceiving it as distasteful (just as adding sugar to other medicines makes them more palatable). Anti-freeze would also come under this category, since dogs do not have the detection mechanisms in place for artificial chemicals that taste applealing. 4) Grapes are considered toxic to dogs though it is important to note that the first reported case of grape poisoning in dogs was in 1998. The Veterinary Medicine Association suggests that grapes and raisins can be toxic and fatal to dogs in rare instances; however, it is unclear as to whether the whole grape can be toxic or if it is just the flesh and skin (and not the seed oil). The Ingraham Academy have had no known instances of poisoning with grape seed oil, which dogs often select with relish and to great effect, however it is a subject that needs further investigation. Sarah Kinson a graduate of the Ingraham Academy, who works with captive meerkats, recently offered them powdered green clay to see their reaction to it; initially they scratched around in the clay and rolled in it. However, she then noticed some of the meerkats taking their food, dusting it and rolling it in the clay before eating it. On further observation, she realized that the only food being taken to the clay was the grapes. The only other food she had seen them roll in the clay was a chick; they are fed dead day old chicks as part of their diet, however she did not see this happen again, only the grapes. Another student had a dog that had a seizer due to eating grapes, however when she read that dogs often select the oil with positive effects she decided to offer the grape seed oil, which her dog continued to take with no ill effect. This made me consider the possibility of if the culprit is mycotoxin (a fungal toxin) found on the skin of some grapes, especially as another student noticed his parrot pealing the skin off some grapes but not others. As green clay is a well -known detoxifier, this could be why they are utilizing it in this way. lso considered toxic to dogs though it is important to note that the first reported case of grape poisoning in dogs was in 1998. It is important to note that very few plant constituents are inherently toxic. A plant secondary metabolite may be detrimental when not needed but can confer health benefits when it is needed (when the correct concentration has been self-administered). For example, we witnessed a young puppy who, instead of eating his food, chose to eat an onion. Onions are normally considered toxic to dogs but not only did the puppy show no ill effects, he also purged a large quantity of tapeworm segments shortly afterwards and then had no further interest in the onion. In the 25 years since we enabled the first animal to self-medicate there have been no reported cases of an animal poisoning itself. N. B. When working with horses, always have a bottle of seaweed, German chamomile and peppermint to hand. Horses are very vulnerable to colic and there are many circumstances that can act as a trigger. For example, horses can get colic from consuming too much of something too quickly. Considering that domesticated animals tend to be deprived from plant secondary metabolites, when some become available they may want to ingest large quantities in a short space of time, which might theoretically induce colic. Peppermint, German chamomile and seaweed are oils that horses with colic select. If an animal does show the effects of tannin poisoning e.g. acorn poisoning in horses, try offering extracts rich in saponins such calendula/marigold and slippery elm or clay whilst waiting for the vet. Clay is good one to offer with other poisonings. ingraham.co.uk/articles.asp
Posted on: Mon, 11 Nov 2013 11:12:29 +0000
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