I have a male dog at home and the vet advised me to neuter it as long as it will not meet another female dog. Is this permissible?

The principle regarding animals is to treat them with mercy and kindness and avoid interfering with their reproductive autonomy except when their reproduction proves harmful. Therefore, when harm is proved in a particular case, it is permissible to neuter an animal following the Islamic legal maxim that states, "Undertake the lesser harm to ward off the greater."

And God Almighty knows best.