I have a "larger" mare that runs phenomanally but would run better a little lighter.  i can't get/keep weight off her.  Her hay is limited, she gets very little grain (just because evryone else gets some) and minimal grass (the pasture in that picture has been eaten down sonce this photo).  She gets about 15-20 miles of long trotting a week.  I know is causing her issus to carry the extra weight but I dont knpw what else to do.  She's very healthy just a super easy-keeper.  What other things does everyone do to keep weight off?  I just dont think it's the best for her knees.

What type of grain and how much?

(1) coffee cup of Nutrena original 2x a day.  Just enough to keep her busy while everyone else eats. First cutting hay about 4 flakes a day no round bale. 

even if that pasture has been eaten down some since that photo, try a grazing muzzle, less feed with less calories and try to keep her more active. I'd take an easy keeper all day over one you have to pour the feed to :)

A girl that runs in our area has a super nice jam up little mare who's definitely on the chubby side. She can't lose weight due to a thyroid issue (I believe) no matter how much exercise she gets. I am not familiar with her feed routine or the specifics of the issue, but it may be worth looking into. 

Then again, my horse also always keeps a little bit of a gut (especially in summertime when she stays on grass 24/7), but only because she's an extremely easy keeper. 

I'm working to get my vet out to check this, too.  She started refusing this past weekend so im concerned she's just struggling with joint or breathing issues due to that belly!

Just remember when you limit their feed you also cut back their energy levels, so they're typically not going to have the energy or stamina to go as hard in a workout or run. Maybe look into a ration balancer vs a grain. Like Renew Gold, Tribute Essential k,  or whatever else may be available in your area. In my opinion, based on that photo, no weight needs to be dropped, she's lean. I won't allow mine to get so thin I can see ribs. Change up her workout routine, build stamina by loping more and doing sprints/breezes. You only mentioned your long trotting routine in the post, which is great but will only get you so far. You have to build the lungs with loping various speeds & sprints, it might just be she needs a stronger respiratory system to fire harder for you. 

Your mare really does look fine to me, I think her belly fat is more of a hay belly, I would increase her feed and maybe less hay since shes out on pasture, do you feed her any Alfalfa hay?  How is her top line?

JMO, your mare isn't overweight, she has hay belly. Hay belly is caused by parasites, poor forage quality, minimal excersise, and conformation (in some cases). Proper parasite control, a probiotic, and excersise will help get rid of it. I'd talk to your vet for more info.

Do you know the exact feed made by Nutrena you are feeding?

I would also recommended a ration balancer if you want her to keep her energy. Stamm 30, Purina Enrich plus, and Triple Crown Balancer 30 are some that I would recommend.

This a better view of her topline.  She eats Nutrena Original.i just think she needs to drop 100#s

She looks good and healthy, I like her When was the last time you had her teeth floated? And just wanted to say that BlueBonnet and Triple Crown make feed for easy keepers. My easy keeper is on Triple Crown lite, good hay a little bit of Alfalfa and good pasture a few hours a day. But hes a bit heavy since I dont ride him much, my fault

A couple years ago on one of my horses people would tell me my horse was fat! everytime I get him to lose he would lose his topline and and actually his belly looked fatter!

A vet talked me into feeding more and put more weight on him, I did and wow his topline filled out, his belly looked smaller, and he no longer looked fat! then people started complimenting on how good he looks!  He has big bones you could say lol and your mare reminds me of mine! and if you cause her to lose more weight you will lose topline!

Horses are meant to eat all the time!

I no longer ration hay! or pasture unless spring time bc of new grass growing and more sugar!

I would never have believed my horse needed more weigh!

We are the #1 cause for our horses problems!

I dont think less weight is going to make that much difference in her knees. 

I would be looking for other reasons for her to be refusing.  Also, all that long trotting can make them sore, maybe look in to changing up your routine.

I guess I'll be the heifer.  THAT MARE IS NOT FAT!!! Nor does she have a GREAT BIG BELLY!.  Sigh... there I said it.  She looks good.  The happy horse is the one that wins and works for you, the Hangry horse won't work an will start getting digestive issues and refuse the gate.  The first picture I can see rib shaddow, that means that she's far from fat.  I'll take a little extra cover any day due to when they work they need the calories to burn.  I've got a Great Big stout mare that is a solid 16 hands, and that 36' cinch looks like a put a 28" cinch on her.  She carries a little belly that never goes away with worming etc.  If I work her a bunch and short her on feed to try and drop the "weight" the top line goes and the ulcers and attitude issues start.  It's the way she's built and nothing will change it.  That belly started after I left her in "the care of someone that I trusted" who starved her.  It's not going away... and I don't care.  

Please stop cutting back on feed.... She looks great in the second picture, and too light in the first one.

if she is fit so what  .. our good mare who won consistenly was fat no obsece but plump  she was fit  and she won.  

if she is fit who cares

I love you!  That great feedback.  I want what's best for her, not me or my ego.  That's why I posted here. Best group of people out there! Thank you 

This is excellent info!  I never thought of it that way.  It makes a lot of sense.  My 5 month old has a larger belly, too and it's probably the same thing! Time to make some corrections! Thank you

Lord help! Leave her alone. You said she runs great. Work on yourself instead.

I think your mare looks just fine.

I myself like to keep my horses "fatter" than most people. I personally do not like to visibly see their ribs. I don't like it. I'm okay with being able to feel them, but not see them. Because the times I load up to go to a weekend race, I want them to have some "extra padding" to put up with that type of stress. JMO.

My Red always carries a little bit of extra weight around his shoulder in that fat bulge spot. But he's in great shape. I would rather have him have a couple extra pounds by being on pasture 24/7 because I know that is healthier for his long term tummy health and circulation. Horses were meant to graze all day and move - not be stuck in a 12x12 stall fed twice a day. JMO on that too!

My Dexter always gets told he's fat. He has the biggest sprung rib cage I have ever seen on a horse! Can't help the body he was given. If people want to say he's fat, so what, I know he's not and that he is properly conditioned and in good shape, and healthy.

Yay!  My new Bestie :)   That mare looks fantastic in the second picture... Pinky Swear