Our guinea pig chews sores on himself. Why? We’ve taken him to the vet for this before and he did skin scrapes but found nothing.

We were told to bathe him in a sulphur shampoo (Seleen) once a week, but it does not seem to cure it. Is there anything else I can use?

M Westley, Faringdon

here are several possible causes for this terrible itch.

The most common in the guinea pig is mange (sarcoptic mange). This is caused by a mite which guinea pigs often carry without showing any signs but it can flare up if the pig is stressed.

Your vet did not find this in his skin scrapes but that does not mean it is not there as it is incredibly difficult to find.

This mite can spread easily to other pets and to humans so you really need to get him checked out again for mites and ringworm (fungal infection).

The mites can be treated by using medicines containing a drug called ivermectin but it may take up to four doses, usually a week apart.

MY chihuahua ate some raisins. My friend says these are poisonous to dogs. I think he only ate two or thre. What should I do ?

A Willis, Banbury

Raisins are toxic to dogs and the trouble is that as little as one-and-a-half grams can cause serious poisoning.

Another problem is that nothing seems amiss for up to two days and then symptoms develop which include vomiting and diarrhoea followed by collapse and often death.

The damage is done to the kidneys and the signs are those of sudden kidney failure.

Treatment has to start as soon as possible and this is likely to include hospitalisation and fluid therapy.

Please do not wait and see. Take him to your vet.

WE have a visiting tom cat who has been around for three years. Our two neutered female cats seem to like him.

He looks terrible though. He is skinny, and is now looking old. Is it okay to take him in and keep him?

G Christie, Botley

Firstly, he may already belong to someone and it would be worth making a few inquiries locally to see if anyone knows where he lives.

Also, you need to be cautious about taking him in as he may already be carrying some diseases which could be passed to your cats.

If he is a true stray he is unlikely to be vaccinated.

He may also carry flu, leukaemia and Aids (immunodeficiency virus).

The last two are particularly common in wandering toms because they get infected by other cats during their many fights.

If you are serious about taking him in, you should take him to your vet who can scan him for an identification microchip, give him a health check and test him for diseases such as leukaemia and Aids.

You must also put an end to his romeo days by having him castrated.