Theobromine is toxic to most animals, but dogs appear to be particularly sensitive. The increased prevalence of theobromine toxicity in dogs is due to their reduced elimination rate, as well as the fact they have easier access to chocolate due to them co-habiting with us. This is supported by the fact that there is a clear seasonal pattern of chocolate poisoning. Theobromine poisoning can also occur in other animals.
In a recent report dairy cows collapsed and died, displaying signs of a disturbed central nervous system (muscle tremors, convulsions) and a reduced body condition score. The herd was fed a total mixed ration (TMR) supplemented with various amounts of chocolate chips (in order to increase their energy intake). Although the exact theobromine dose during the time of the incidence is unknown, and information about toxicity of theobromine is limited in ruminants, it was concluded that the feeding of chocolate in this case caused all signs including death of the cows. No other causes for the signs were established, and the problems at the farm stopped after removing the chocolate from the TMR.