Sudden aggression in 7 yr old mare

[targetsmom]

We have had Ruby since she was a weanling and she is now 7 and never bred (and never will be by us). She has always gotten along well with everyone and is the one we use for company in the trailer or as a turnout buddy for new arrivals. But during the week after the October snowstorm (when our power was out all week) she suddenly became aggressive and started fighting and squealing with Dancer, our most recent addition. Since they had been turnout buddies from day one, this was a huge surprise and we first figured it was an issue with Dancer. But when Ruby went after the gelding that has been around all 7 of her years here, we realized it was her and separated her from the herd. We do think she was in heat, and that Dancer was also in heat, when this started, but that was three weeks ago and the problem has continued all this time. She will even squeal at the others from her side of the fence in her solo turnout area. The other minis seem to still want to be friends and are very confused!

I contacted my vet and we have two ideas: 1) a hormone issue, so I put her on Regumate 3 days ago (11/17). 2) Lyme Disease, and we await test results from blood pulled 11/17. Does anyone else have any other ideas? If it is a hormonal issue, how long before the Regumate might show some effect? Any other tests we should run?

Ruby actually seems content in her solo turnout area(s), which include the back yard when Dancer isn't there. She is not actually aggressive toward people, but does sometimes seem sore in places. She does not seem lame at all and runs and jumps willingly and normally. Vet looked at her teeth and those seem fine; she eats, drinks and poops normally. Right now she is in a turnout next to our stallion and he shows no particular interest in her. We are baffled and will appreciate any suggestions.

 

[chandab]

I honestly don't know, but going along the same lines as the vet's suspected hormonal issue. What about a retained follicle (or whatever they call it when they don't mature and release normally)?

 

[Eagle]

My stallion turned aggresive last year, it was the first sign he gave me that he wasn't well. He was treated for ulcers and he is fine now. Has she been under any stress?

 

[drmatthewtaylor]

My first thought was a 'hormone' issue too, but I respectfully disagree with using Regumate as a diagnostic as well as a therapeutic tool. I doubt it will do either.

The most likely cause of a hormonal issue is Granulosa Cell Tumor which is a benign hormone secreting ovarian mass. The best way to diagnose it is an ultrasound.

Horses do not get ovarian cysts.

Dr Taylor

 

[Jill]

Hormonal issues are my hunch, for whatever that is worth. I used to know a QH mare who had sudden aggression and it was related to cysts on an ovary. I think both ovaries were removed (maybe just one, but I do think both). After recovery, she was fine. She was a young girl's show horse, so it was a big deal that she be "level" and she had started attacking the kid and trainer.

 

[StarRidgeAcres]

I don't know for sure Mary, but I too suspect something about her reproductive system.

My only experience with anything like this was a few years back. I traded a beautiful buckskin stallion for a broodmare. The mare hadn't foaled in a couple of years but I was told that was due to owner and not anything to do with the mare. When I got her she was obese. I brouht her home and things were ok for a while but then she turned aggressive toward the other mares. Never toward me. But it got worse and worse. To the point where I literally was concerned she was going to kill my mare Sweet Pea because when they would go at it, SP was very dominant so she wouldn't back down and neither would the other mare. It was like a living nightmare. She fought with any mare that dared come near her and she would even proactively go after them even if they weren't paying her any attention. One of the fights broke out when my vet was there and she got to witness it. She said she'd never seen a mare be that aggressive before either. We toyed with doing some tests on her, but honestly I just wanted the owner to take her back. I finally got the owner to agree to take her back as I could not deal with her anymore.

I recently learned through a sale ad that she is available again, but they are advertising her as a "pet" and say she doesn't get in foal anymore. I believe this mare has had an issue for years and that was causing her behavior. I also learned the owner blamed me for her aggressiveness. They said I didn't feed her enough so she was fighting for food. Well, she did lose weight with me because she NEEDED to! She was obese when I got her. She had PLENTY of feed and hay while here, but she spent most of her time chasing after and fighting with the other horses. So yes, she did lose weight, but she was not starving or even close. She just was aggressive to the point of being unacceptable. And now with her being sold as non-breeding I do believe she's had a problem for a long time now.

I with the best for you. I know you will give her the care she needs for you to figure out what the cause is. I do think there's a big chance the regumate will do the trick!

 

[targetsmom]

Thank you all - especially Dr. Taylor. The vet that was here is not the one that does ultrasounds, so it sounds like I may need a visit from the vet that does do them.

ETA: I did think of ulcers and started her on U-Gard, but she is eating normally. On the other hand, normal for her is mostly alfalfa cubes and little grain because she has always been fussy. And this was so very sudden, plus no other signs of ulcers. But she is still on the UGard just in case.

 

[midnight star stables]

My first thought was a 'hormone' issue too, but I respectfully disagree with using Regumate as a diagnostic as well as a therapeutic tool. I doubt it will do either.

The most likely cause of a hormonal issue is Granulosa Cell Tumor which is a benign hormone secreting ovarian mass. The best way to diagnose it is an ultrasound.

Horses do not get ovarian cysts.

Dr Taylor

Dr Taylor, If that were the issue, what would be your recommended treatment?

Those with aggressive mares, do you find that they only act aggressive to other mares? What about foals or geldings(I realize the OP mentioned that her mare was also aggressive to a gelding, so I may have answered my own question there)?

My own experience with this area is with my joyful mare Joy, who is known to be aggressive to horses lower in the pecking order and sometimes moody towards people. It wasn't really sudden in our case, but our thoughts have been either ulcers or hormonal.

I hope your mare improves Mary, and I'll be watching this thread for updates.

 

[JAX]

I have never used Ugard so I dont know but IF it is an ulcer preventative and not for ulcer treatment, I would try something like Omeprazole (UlcerGard, GastroGard) just make sure to use the treatment dose instead of the preventative dose. Ulcers can definately make a horse grumpy and unfriendly, and sometimes they eat just fine with them. For most of my guys a tube of either of the above mentioned lasts 5 days at treatment dose. I wouldnt have a clue what to tell you if it is hormonal related...

Hmmmm...Almost forgot I do have a mare who gets somewhat uncomfortable sometimes either before or during her heat cycle, my vet said she has large folicles and she goes back to acting normal after her heat cycle.

 

[Eagle]

My guy with ulcers ate normally the whole time, this is why it took so long to find out what was wrong. The vet still didn't agree with me and said it could be a waste of money as a box of Gastrogard here in Italy is about $270 but I was prepared to try and he is fine now.

I can't help with hormone problems sorry.

Good luck, I will be praying for her

 

[drmatthewtaylor]

Dr Taylor, If that were the issue, what would be your recommended treatment?

Those with aggressive mares, do you find that they only act aggressive to other mares? What about foals or geldings(I realize the OP mentioned that her mare was also aggressive to a gelding, so I may have answered my own question there)?

My own experience with this area is with my joyful mare Joy, who is known to be aggressive to horses lower in the pecking order and sometimes moody towards people. It wasn't really sudden in our case, but our thoughts have been either ulcers or hormonal.

I hope your mare improves Mary, and I'll be watching this thread for updates.

Treatment of choice for a GCT is surgical removal of the ovary. Sounds pretty drastic, but really a pretty easy procedure that most mares do well with. Usually only one ovary is affected and once it is removed the other ovary will function normally.

Signs of the condition are dependent on what hormones the tumor secretes and range from stallion like behavior to nymphomania and everything in between.

Dr Taylor

 

[targetsmom]

I may re-think the ulcer possibility and start her on Gastroguard, which I have on hand anyway. The week this started was incredibly stressful for everyone within 200 miles of us! We had 12 inches of wet snow (in October) which knocked out our power for a week. Meant the feed schedule was slightly changed so we could feed while it was light. Their turnout area was confined so they couldn't have access to all the branches that fell into it. We were still cleaning those up yesterday to expand the turnout area back to normal. As the snow melted, the mud was incredible - NO ONE wanted to walk in it; At least the minis didn't get their boots pulled off and end up walking in their socks. Needless to say the people were stressed and the minis for sure must have felt it. We were lucky we had a generator and did not run out of grain (or food), as you could not buy ANYTHING for several days (gas, feed, medications, etc). We were supplying water for neighbor's horses.

Will keep you posted!

 

[targetsmom]

Update 11/28:

Got the Lyme Disease results back 11/21 but have not acted on them:

ANIMAL ID: Ruby SPECIMEN TYPE: Serum

TEST REQUEST SPECIES BREED SEX AGE RESULTS & COMMENTS

Lyme ELISA Equine America F 7Y Moderately POSITIVE @ 1:2560

Lyme WESTERN BLOT Equine America F 7Y Mildly POSITIVE: Indicates recent or resolving Bb

infection. Retest in 3 to 4 weeks for confirmation of active Bb infection.

Ruby's moderately high titer may be due to a moderate response to nonspecific antigens on the

Western blot. The blot still shows a mild response to Bb-specific antigens.

_________________________________________________________________________________________

My vet wants to treat but I want to wait. My other horses that were treated for Lyme weren't treated until or unless they had much more clear-cut positive results!

So far Ruby has been on Regumate for 12 days and GastroGard for 7 days. She SEEMS to act better, but since we are keeping her by herself we can't really know. We are a bit reluctant to find out HOW MUCH BETTER she might be. That could be dangerous for all concerned - equine and human - since she was rearing on the lead and kicking anyone nearby. She has not been aggressive toward my husband lately (she was not aggressive to me at all, so we need him to be the guinea pig!). We also turned her out with one of the yearlings and she was fine toward him, and is now out with the other yearling (a mare). I guess we are treating her the same way we would a new herd member, except RUBY was always the one we used as the first turnout buddy.

If anyone has any suggestions as to how we can safely find out if she is better, please share! Of course if she is better, we won't know what worked....

 

[Eagle]

I am glad she is looking better

When my stallion had ulcers and was very aggressive I put him alone then after a week of Gastrogard he seemed happier in himself so I put a buddy on the other side of the fence, before he would have made faces through the fence but he seemed o.k so I let his buddy out into a neutral area and put the stallion on a lunge line and let him out too. The lunge line was to pull him in if he got aggressive but it was obvious by his behaviour that he was very happy to be back with his friend.

I have had no problems with him since then, he has just finished his treatment of gastrogard after 6 weeks.

I think you will need to continue her treatment also as they say 4 weeks on full dose and then 2 weeks at a reduced amount. I have no experience with Lyme disease so I can't help, sorry