Thank you for your question.

Dirofilaria immitis is known to infect a range of species (dogs, cats, wolves, foxes, ferrets, and occasionally people) but the ruminants are not common carriers. That said even if by a twist of fate D. immitis infected her goats, it would be of limited direct risk. This is because this is a parasite that has an obligatory mosquito stage. This is to say that it actually develops while being carried by the vector rather then just using the mosquito as transport.

Therefore, the 'true source' of infection would be the mosquito and you could argue that any of the aforementioned animal species in range of her location could have been the infected (rather then just her own animals) and thus the risk.

And since there is an obligatory life cycle step that requires a mosquito and there is no direct passage of the parasite via milk, there is not a recognized risk associated with drinking milk from infected animals. Therefore, milk is safe from these animals.

So, if one is worried about D. immitis infection then mosquito control would be an important prevention measure (and testing the animals would be helpful too).

I hope this information is helpful.
Please do let me know if you have any further questions.
If you have no further questions, feedback is always appreciated.

All the best,