Thursday, October 29, 2020

 Moody mares may benefit from ovariectomy to alter their behaviour and rideability, according to a recent report.

Some mares are difficult to manage and perform poorly as a result. They may be uncooperative or aggressive when handled on the ground. They may kick, buck or rear when ridden or may be aggressive towards other horses.

Unwanted behaviour may result from pain from orthopaedic or other sources. Sometimes it is related to the mare coming in season, in which case it may be improved by suppressing the oestrus cycle.

Some ovarian tumours, although less common, may produce similar effects. Treatment of these cases is likely to involve removing the affected ovary (ovariectomy).

But sometimes there is no obvious explanation for the unwanted behaviour. Would removing both ovaries (bilateral ovariectomy) help?

A study by Daniel Taasti Melgaard, of the Horsholm Equine Clinic, Fredensborg, Denmarkand colleagues looked at whether removing the ovaries from mares with unexplained unwanted behaviour improved the mare’s behaviour or rideability.

Twenty-eight mares underwent surgical removal of both ovaries once the clinicians had ruled out painful causes and after the mares had not responded to a trial period of hormone therapy to suppress oestrus behaviour.

Owners reported that, after bilateral ovariectomy, 80% (8/10) of mares with normal ovaries and 57% (8/14) of mares with ovarian neoplasia were easier to ride. Behaviour was reported to be better in 40% (4/10) of mares with normal ovaries, and in 43% (6/14) of mares with ovarian neoplasia.

A full, open access, report is published in the journal Animals.

The authors emphasise the importance of a thorough diagnostic work up to rule out other conditions, such as orthopaedic, alimentary, vaginal or uterine pathology, before considering ovariectomy for unwanted behaviour.

They suggest that, despite the significant improvement observed in the present study, further research is necessary to confirm whether mares with unwanted behaviour not obviously related to the oestrus cycle and to painful conditions may benefit from ovariectomy to alter their behaviour and rideability.

“In conclusion”, they write, “a significant improvement was observed in rideability and behaviour post- ovariectomy, but no statistical difference in improvement after ovariectomy between mares with ovarian neoplasia and mares with histopathologic normal ovaries was observed. The results suggest that mares with and without neoplasia can equally benefit from ovariectomy to improve behaviour and rideability.”

For more details, see:

Moody Mares - Is Ovariectomy a Solution?
Daniel Taasti Melgaard, Trine Stokbro Korsgaard, Martin Soendergaard Thoefner, Morten Roenn Petersen, Hanne Gervi Pedersen.
Animals (Basel) (2020)
doi: 10.3390/ani10071210


Max said...

I find it tragic that a horse is described as behaving badly because she is in pain, and that the solution is to remove her ovaries so that people can sit on her back for their own pleasure. It's pretty barbaric when you think about it.

zipZap said...

Yes - this study throws up a whole lot of ethical issues

Anonymous said...

I wouldn’t consider those %’s satisfactory for the cost of surgery or for the invasive surgery needed. Maybe I’ve been very lucky but Ive ridden & preferred mares all my life, that’s apx age 8 to 72 years, & never had one that was unrideable or aggressive when in season. Not all were mine so I did not always have any say in how they were kept.

zipZap said...

No examination of riding style considered? When contradictory aids, unhealthy and painful head / neck postures are the order of the day, extreme levels of rein contact and tight nosebands is a bad behaviour when a mare is not tractable ? Change the riding rather than resorting to an equine version of ‘The Hand Maiden’s Tale’

Unknown said...

I was pretty appalled too. As a breeder (though just 'retired') I could write a book on behavioural differences in mares: even mares with very close bloodlines, and home-bred mares I kept on as brood mares. And the differences MIGHT be between not in season - and in-season, behaviour at covering, behaviour during and after foaling, and at weaning! And similar with stallions. Stallions that are 'bad' or even dangerous during covering, and how 'different' they are when the decision is taken to castrate a stallion after he's been 'used', or before he gets the chance. The only horses that don't show hormone led behaviour of SOME sort are geldings (even with those, you need to test that there are no remaining hormones.

Just a month ago, I had a home-bred 6yo gelding (gelded as a yearling)tested, because of his obsession with cosying up to mares over the fence. He had none! But just yesterday, my rider noticed a clicking sound and a reluctance to go forward that had JUST become apparent. Today, I watched him on the lunge for just a few minutes and definitely saw pain. So no more work until after the physio comes on Monday. And I suspect it will be quite a long job getting him 'right'!

I am in no doubt at all, the vast majority of behaviour problems (at least in horses that have been properly brought up) IS pain!! It may be slight, niggling discomfort - or acute pain (and that is normally 'easy' to spot. But I have sold home-breds that have never shown any sign of behavioural problems in their lives, until they go to a new home! The time taken varies from a few days (seperation anxiety IS very real even with good management) to 6 months or more. When the new owner wants to send a horse back after 6 MONTHS - and doesn't even ask for money back - just wants rid - the answer is usually easy to find. With one, wither painful from an ill-fitting saddle, and hind-gut ulcers; and another, just hind gut ulcers due to poor feeding and no turnout! Both mares - and both finally demonstrated their 'unhappiness' by bucking. Both were quite easily cured - my fault for being fooled into thinking the first owners were 'suitable'!

Of course, you 'tell a gelding, ask a mare, and negotiate agreement with a stallion' isn't too far from the truth! The only MAJOR problem with mares behaviour wise that IS 'hormonal' is a granulosa theca cell tumour, Fortunately quite rare, and slow to get to danger 'level'. That is about the only thing that would lead me to remove at least one ovary!

Unknown said...

Not sure whether I agree or not.
Reason why. I have PCOS. Hormone issues. Mares cycle like Humans, are they testing the mares hormones and finding out if they are balanced or not. In us women with PCOS and menopause we go through so horrible symptoms.

Can giving hormone replacement help mare like it does in menopause women. Bioidentical hormone replacement.

Instead of removal of organs etc.

Minka Kulenovic said...

What next we are going to do to our domestic animals and not only to to the horses, just to be easier to handle them for the human pleasure, profit, and ignoring their quality of life and the stress of every day 'domestication'? Not surprising that Mother nature is sending the message with COVID - 19? There is hardly any empathy left for the animals sufferings their daily existence without proper medical care and empathy? Just think about it with your procephalic brain!!!

Unknown said...

Pain was ruled out as cause of undesired behavior

Unknown said...

Why? Stallions are routinely castrated.