We mostly recommend neutering of female dogs at 6 months old (before their 1st season) but the vet will advise on an individual basis. However, it can be done at any stage of the bitches life, preferably 3 months from her last season to avoid oestrus.
The reasons that neutering is recommended is the elimination of season and false pregnancies, a reduction in the incidence of mammary tumours (this protective effect is progressively lost the more seasons that she has prior to spaying) and to eliminate the chance of developing pyometra (a life threatening condition caused by infection in the womb).
Male dogs can be castrated from 6 months. This helps to eliminate unsociable sexual tendencies, significantly reduce prostatic disease, and anal gland adenomas and to help reduce aggression.
We recommend neutering of both female and male cats if they are not required for breeding. This can be done
from 6 months onwards.