Breeding and Neutering

Breeding is a project, not an event, and most litters that cause difficulty were never planned at all. The starting point for any new owner is simple: know when your species becomes fertile, because it is usually earlier than expected.

Puberty arrives early

• Bitches typically have a first season between six and twelve months, later in giant breeds, and come into season roughly every six months, for about three weeks each time.
• Cats can breed from around four months. Queens cycle repeatedly through the lighter months and ovulate in response to mating, so a kitten can be pregnant before she looks grown.
• Rabbits mature at four to six months, and ovulate on mating. Littermates must be separated before then, brothers included.
• Guinea pigs, rats and mice mature startlingly young — young males need separating from their mother and sisters within weeks of weaning.
• Ferret jills stay in season until mated, and prolonged oestrus can cause fatal anaemia. An unbred jill needs a management plan — an injection, an implant, a vasectomised hob or spaying — arranged in advance of the breeding season, not afterwards.

Mixed-sex groups of any small mammal should be arranged with this in mind. Two litters can arrive from one unnoticed pairing before the first is weaned.

What neutering does and does not do

Neutering prevents unwanted litters, and in females it removes the risk of pyometra — a womb infection that is common in unspayed bitches, queens and rabbits, and frequently an emergency. Spayed rabbits avoid uterine cancer, which is very common in unspayed does by middle age. Early spaying reduces mammary tumour risk in dogs and cats, and castration reduces roaming, fighting and territorial spraying in tom cats.

It is not a behaviour cure. Nervousness, reactivity and poor recall are training and management issues, and in some dogs castration can make anxiety-driven behaviour worse. Neutered animals also need slightly less food; weight gain afterwards is caused by unchanged portions, not by surgery.

If you are thinking about breeding

Do the arithmetic honestly. That means health screening appropriate to the breed, knowing the inherited conditions in the line, an emergency fund for a caesarean, homes arranged before mating, and time free for the weeks around whelping or kindling. Some breeds and body shapes carry known whelping risks. In England and elsewhere in the UK, breeding beyond a small number of litters a year requires a local authority licence, and the rules on selling and advertising young animals have tightened — check the current position before you start.

Whichever way you decide, decide early, and take qualified advice on timing for your individual animal.