Metabolic Horse Syndrome? ?

My vet came out to see my mare Thursday and she said that my mare is metabolic. My mare needs to lose 50-100 lbs. I have limited her pasture time from 10am until 7pm instead of 24/7, but keeping her grain the same. I am also exercising her every other day instead of 2x a week. And I'm considering buying a grazing muzzle.
What are some healthy ways for her to lose weight?
What are some do's and don'ts for using a grazing muzzle?

Also, being metabolic, she is prone to laminitis, although she DOES NOT have it. Yaaay! And the vet said that my mare doesn't have cushings? Are the two related, or similar? I've never dealt with either of these before.

Sagaciousness~Thanks for that informative website! After reading all that, I am also very surprised that my vet didn't want me to take my mare off grain. She left this weekend and will be out of town for 2 weeks. She said she would email me some more info when she gets back, but I don't want to wait that long to start my horses new exercise and diet.

Equine metabolic syndrome includes cushings, insulin resistance, and adrenocortical hypersecretion. Your horse sounds like she is insulin resistant. Has the vet tested her hormones? A definitive diagnosis is verified that way. If she is IR, she should be taken off grain altogether. Grass hay, no alfalfa or clover in it, should be fed. A Best Friends grazing muzzle is the only one I recommend....I have the deluxe, which I also recommend. It comes with instructions which you should read and follow. Check with your vet for any mineral supplementation your mare should have. since she is overweight, hay alone, plus limited grass, should sustain her.
You can safely begin reducing her grain ration. If you want to feed something to replace it, Purina makes a new product called Wellsolve L/S formulated for IR horses, which you can look up online for more information. Good luck with your mare...I'm glad you are doing this before she experiences laminitis.

EDIT...I just read zoetodman's post...they have new research that has dispelled chromium as a factor in IR and are now saying it is magnesium that should be supplemented.

I believe the correct name is Equine Metabolic Syndrome.

Cushing鈥檚 disease and Laminitis both fall under the umbrella of Equine Metabolic Syndrome because they are both caused by a similar metabolic issue, relating to the horse's inability to process sugars (much like a human diabetic).

Physical symptoms include excessive fatty areas in the shoulders, rump, and cresty necks that can thicken and harden. These horses also have a specific blood profile.
Cushing鈥檚 horses鈥?often are seen with a thick, curly coat that is late to shed or does not shed at all, although laminitic horses can also suffer from this symptom.

Healthiest ways for your horse to lose weight include gradually increased exercise and various diet restrictions. Most EMS horses are limited to quality grass hay in measured amounts.

I am surprised that your vet is allowing you to continue your mare's grain, because grain has been shown to be extremely detrimental to horses with EMS.

I would not just consider the grazing muzzle, I would go out and buy one ASAP. Grass contains high levels of sugar, which puts your mare in more immediate danger of founder and laminitus.

Here is a great article on EMS, with lots of tips and information:
http://www.ker.com/library/EQUINEWS//v9n...

Good luck!

Both answers already posted are excellent and I agree wholeheartedly with the grazing muzzle and my suprise at the fact that the vet said keep on with the corn, but thought I would also mention possible Chromium deficiency and a link to IR. Chromium works with insulin in the metabolisation of sugar in the body, helps transport protein to where it's needed, helps form part of glucose tolerance factor(GTF)along with vitamin B3 and 3 amino acids-glycine, glutamic acid and cystine. It helps balance blood sugar, help normalise hunger, reduce cravings, improves lifespan, protects DNA and RNA, essential for heart function. You don't say how old she is, but as you get older the ability to retain chromium lessens. The fact she is a mare is also of interest as I have only ever seen this in mares..but that is maybe chance !. Speak to your vet when she returns
about possible deficiency, it is possible to supplement..but NOT without vet advice and monitoring as toxicity can occur in very high doses(chelated Zinc is a good substitute if Chromium not available). Brewers yeast is the best natural source and horses on the whole find it palatable. Hormone imbalances are often at the root of Chromium deficiency, as are being overweight and lack of exercise...both of which you are on to !! :o) So glad she hasn't got the dreaded 'L' word, well done for acting before it got to that stage.
good luck and please update with her progress sometime
Zoe