How much rumbling and mounting is normal for a sow?

Q: How much rumbling and mounting is normal for a sow?

Dear Experts, We need advice concerning one of our female piggies.

Both Clover and Dandy, are just over three years old, in good health, and live in a spacious 5×2 indoor cage. They also get occasional fresh air and exercise in an outside run on the lawn. Clover can be particularly hormonal, but it normally only lasts about two or three days. 

However, this time it has lasted a good week to ten days, and she is really pestering our other girl Dandy, to the extent of rubbing against her, and trying to mount her constantly, and generally not giving her any peace. 

She also seems to wander about seemingly rumbling at nothing! In all other respects she is fine, eating, drinking, pooing etc. and shows no signs of any discomfort. Is this ‘normal’ behaviour, or should we visit to the vets, and is there a medication to ease the effect of hormones?

A: Abi Eddis

This may be the start of some cystic ovary issues, as often these piggies will show increased horizontal activity. If it’s not settling down then I would consider heading to a good exotics vet and potentially having her ovaries scanned for cysts. If she has ovarian cysts then it would be best to spay her. 

If she doesn’t you may be able to try a hormone implant to help calm her down a little but there isn’t much research to say this will definitely work. I recently did an implant on one of my elderly boars and so far seems to be going well but it might not work for all piggies.

A: Agata Witkowska

Hormonal problems are a common issue in middle aged guinea pigs, in particular when associated with ovarian cysts. 

Just like other rodents, guinea pigs can mate frequently and so come into season often, and this, as a species, can predispose them to hormonal issues. Some mild behavioural changes during their season are normal, however when they persist it may be a sign of underlying disease. 

As a prey species, guinea pigs can hide signs of underlying problems well, and so will often show only behavioural changes even if ovarian cysts, tumours or uterine problems are present. Since the behavioural changes have been persistent I would recommend you take her in for a check up with your vet – treatment will depend on what is found. 

A: Katharine Frayling

Hormonal problems can be a fairly common issue with female guinea pigs as they get older especially if they haven’t had any litters. They might exhibit mounting and chasing when going into season roughly every 3 weeks in their first few years of life but a further flooding of their hormones can cause ongoing behavioural problems. 

Sows can get a condition called ovarian cysts which are fluid filled cysts that develop near the ovaries. These cysts elevate some hormones such as oestrogen which leads to irregular reproductive cycles. Other symptoms can be bilateral hair loss along the sides, a change in shape due to weight redistribution, nipples enlargement which may also become crusty along with sexually aggressive behaviour. 

It would be a good idea for your vet to explore whether your guinea pig may have cysts either by palpating her abdomen if they are large or by investigating using an x ray or ultrasound. Some vets may drain the ovarian cysts with a follow up of a hormonal injection HCG (Human Chorionic Gonadotropin) or just give the hormone injection with follow ups to help shrink the cysts. In more serious cases, a guinea pig may need an ovario hysterectomy (spay). 

A further treatment I have known some vets to try is by using a slow release GnRH implant for the treatment of ovarian cysts.


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