Hello again Gary,
I have worked out an answer for you, well Trooper is not very big but from my calculations I do not think this incident will present him with much of a problem. There are no special measures you need take other than just keeping an eye on him. Please see below ...
While chocolate can be toxic to dogs they have to eat quite a lot, probably very much more than Trooper ate before you would see signs of toxicity.
1. The rule of thumb which I apply is that with milk chocolate mild signs of toxicity can occur when 0.7 ounces per pound of body weight is ingested. Severe signs occur when 2 ounces per pound of body weight is swallowed. If you estimate your dog's weight as being in the region of 10 lb then you can see that your dog would have to swallow around 7 ozs of pure milk chocolate before any symptoms would even start to occur.
It would be very unlikely that the chips in one cookie will come up to be anywhere near this weight which after all is not so far from half a pound.
2. I am telling you the following just for your information as your dog ate so little you need not do anything and need not be concerned.
The symptoms of chocolate poisoning would include vomiting and diarrhoea as well as frequent urination, and restlessness in the early stages. This can then progress to cardiac dysfunction, tremors and fits. Of course you should call your vet without delay if any symptoms appear.
Having said that most dogs with chocolate poisoning will recover within 24 to 48 hours, particularly if serious symptoms do not occur. There is no specific treatment for chocolate poisoning only symptomatic treatment.
3. Here is a link which covers chocolate toxicity in the dog in more depth : LINK
I hope I have covered your question fully enough but if you would like further clarification or to talk things over a bit more then I will be on-line for the next hour or so and I will be more than pleased to continue working with you.
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