Dog eating cat feces

Question
Our 10 month old Boston Terrier has the awful habit of eating cat feces. After going outside and having his "snack" he comes into the house and throws it all up. This can't be good for him, since our cats are outside cats and have never had any vet service, we keep them just to keep the mice population down on our farm. He started this behavior when he was about 5 months old.
He doesn't eat his own feces as far as we can tell, just the cats. We would like to know how to get him to stop this behavior, since the neighbors will be using our pasture for their horses soon, and we don't want him to start eating that too! We have tried watching him outside and have yelled at him when we catch him in the act, but we can't watch him the entire time he's outside, We don't want to get rid of the cats either since we live on a farm and they are good mousers. I have heard about some type of powder to put on their food to make the taste of the feces unpleasant (as if it wasn't already) does that work? and what is the name of the product? How long would we need to feed this to the cats, and what if they didn't eat it? We were thinking of trying a shock collar, to deter him from it, is that recommended?
Any suggestions are greatly appreciated,Thank you

Answer
Hello!

I personally don't like shock collars. Plus this would only work if you see him doing the behaviour, on times you don't see him he may still keep doing it. I think that we should first consider ''why'' he is doing it, rather than how to stop it. This problem referred as coprophagia is usually caused by nutritional deficiencies among with some other likely problems of course. It may be sometimes considered natural, although not normal, behaviour for dogs to consume the feces of ungulates containing large amounts of nutrients remaining after large intestinal fermentation, which may helped to sustain dogs in the wild when no other food source was available. Dogs also commonly eat the feces of cats with whom they share a household. If he is eating his own feces, this may also be a behaviour problem responding to punishment for defecating in inappropriate locations by removing the evidence and imitating the owner's behaviour of removing feces. It may sometimes be caused by medical causes such as hyperadrenocorticism, intestinal parasitism, etc. So the treatment would vary depending on the underlying cause. You may want to first try and see if he has nutritional deficiencies. Are you feeding him an appropriate nutritionally well balanced diet? If not, please try to adjust on that. Another you may try is coprophagia tablets available from many brands, one I know is 8 in 1's Pet Deter Coprophagic Treatment, but I am sure you may find it in other brands too. This may help, but you have to be patient,it's not going to stop the behaviour right away. It would also be a good idea of getting him dewormed if it is not being done regularly, since he may have gotten lots of intestinal parasites. Please keep me informed on how it goes.

Kind Regards,
Caglar Kondu Erkip,DVM