Eleanor M. Kellon, VMD
Ever watch "My 600 lb Life”? The advice to allow free access to food for an obese horse — or human for that matter — is doomed to failure. Too much food is how they got that way in the first place. Things like age, metabolic rate, and activity level can influence what calorie requirements are, but it still boils down to too many calories in versus calories burned. The same is true for overweight cats, dogs, and people.
Obesity comes from overeating. With overweight glucose-sensitive horses, the diet has to have both controlled sugar and starch plus controlled calories.
Let's look at some of the claims floating around:
Claim: Horses need to be able to eat 24/7 because that is what they do naturally.
Fact: The only reason "natural" horses on pasture spend so much time eating is that grass is about 80% water. On a calorie basis, even low-sugar and starch hay has approximately 450 to 500% more calories per mouthful than fresh grass.
Claim: Restricting forage leads to weight loss that is mostly muscle, as well as raging hormones, oxidative stress, leptin resistance, and even Cushing's disease.
Fact: Where is the proof that any of the above is true? There is none. For example, long-standing research has clearly shown the stress hormone cortisol is higher when horses are fed than when they are restricted from eating. (References below.) Controlling access to food does not increase any hormones or cause oxidative stress, or Equine Metabolic Syndrome (EMS). Weight loss that is mostly muscle never happens unless all body fat has already been burned.
There's much, much more in equine research literature.
Does the horse need constant access to food to avoid being mentally and physically traumatized? Absolutely not. Horses with a healthy body weight restrict their food naturally and do not eat 24/7. The leptin resistance and increased appetite that makes EMS horses overeat has nothing to do with how often food is available. There is strong evidence EMS is an inherent metabolic type, determined by genetics. Allowing them to indulge will never make it go away.
Returning horses to their natural state is the argument given in favor of free-choice feeding, even for obese horses. The fact of the matter is that, unless you have 200 acres of scrub pasture available, you cannot replicate an equine natural state. Traveling double-digit miles every day to find adequate food is the major difference. A paddock paradise set-up does not even come close to the miles needed. Only horses in endurance training and racing come close to the exercise level of a natural state.
I have followed thousands of horses with metabolic syndrome and Pituitary Pars Intermedia Dysfunction/Cushing’s (PPID) for the past two decades on the Equine Cushing's and Insulin Resistance group — current active membership is over 12,000 international members. https://ecir.groups.io/g/main. Drastic reduction of intake is not necessary to control weight, but you cannot allow unlimited access.
To obtain weight loss safely, ECIR has always used the starting point of 1.5% of actual weight, or 2% of ideal weight, whichever is larger, as the target daily hay intake (i.e., 2% = 20 lbs for a 1000 lb horse). It may need to be adjusted down a bit for higher calorie hays. This rule of thumb is nothing new. It's straight out the National Research Council (NRC) recommendations for feeding horses. It works — quickly and effectively.
To give you some perspective, the most-recent edition of the NRC added an easy-keeper category to their calorie requirements. An inactive 1100 lb/500 kg horse is estimated to require 15.2 Mcal/day in calories. If your hay has 0.9 Mcal/lb, that's only 16.8 lbs of hay a day. In contrast, a horse on pasture is estimated to consume 5 to 7.5 pounds of grass an hour. Left to their own devices, horses have the capacity to eat much more than they need when the food is a more concentrated calorie source than fresh grass.
To help keep them at ideal weight, as much exercise as possible is indicated: turn-out in a paddock or out in a pasture with a muzzle, hand walking, and progressive riding once all evidence of laminitis is gone. The calculated daily hay allotment can be provided in a slow-feeding set-up, like small-hole hay nets to reduce boredom — but is never given free-choice. The outcome is as predictable as unlimited zero-carb pork rinds for a human battling an excessive appetite.
The battle of the bulge isn't fun for man nor beast. Giving in to the compulsion to eat is not the answer.
Additional Reading: You Can’t Always Follow Your Gut With An IR Horse https://wp.me/p2WBdh-qq
Feed deprivation of mares: plasma metabolite and hormonal concentrations and responses to exercise.
- S. Sticker, D. L. Thompson, Jr, L. D. Bunting, J. M. Fernandez, C. L. DePew, M. R. Nadal
Journal of Animal Science, Volume 73, Issue 12, December 1995, Pages 3696–3704, https://doi.org/10.2527/1995.73123696x
Changes in concentrations of hormones, metabolites, and amino acids in plasma of adult horses relative to overnight feed deprivation followed by a pellet-hay meal fed at noon.
- L. DePew, D. L. Thompson, Jr., J. M. Fernandez, L. S. Sticker, D. W. Burleigh
Journal of Animal Science, Volume 72, Issue 6, June 1994, Pages 1530–1539, https://doi.org/10.2527/1994.7261530x
The effect of a limit-fed diet and slow-feed hay nets on morphometric measurements and postprandial metabolite and hormone patterns in adult horses.
J Anim Sci 2015 Aug;93(8):4144-52. https://doi.org/10.2527/jas.2015-9150
Hormonal patterns in normal and hyperleptinemic mares in responseto three common feeding-housing regimens. W. A. Storer, D. L. Thompson Jr., C. A. Waller, and J. A. Cartmill
School of Animal Sciences, Louisiana Agriculture Experiment Station,Louisiana State University Agricultural Center, Baton Rouge 70803 https://pdfs.semanticscholar.org/46f2/ddb82bd931e7fcbe6e7bc856d80ec6423839.pdf
Triglyceride, Insulin, and Cortisol Responses of Ponies to Fasting and Dexamethasone Administration J. F. Freestone, BVSc, K. J. Wolfsheimer, DVM, PhD, R. B. Ford, DVM, MS, G. Church, MApStat, and R. Bessin, MApStat, PhD https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1939-1676.1991.tb00925.x
About ECIR Group Inc.
Started in 1999, the ECIR Group is the largest field-trial database for PPID and EMS in the world and provides the latest research, diagnosis, and treatment information, in addition to dietary recommendations for horses with these conditions. Even universities do not and cannot compile and follow long term as many in-depth case histories of PPID/EMS horses as the ECIR Group.
In 2013 the Equine Cushing's and Insulin Resistance Group Inc., an Arizona nonprofit corporation, was approved as a 501(c)3 public charity. Tax deductible contributions and grants support ongoing research, education, and awareness of Equine Cushing's Disease/PPID and EMS.
THE MISSION of the ECIR Group Inc. is to improve the welfare of equines with metabolic disorders via a unique interface between basic research and real-life clinical experience. Prevention of laminitis is the ultimate goal. The ECIR Group serves the scientific community, practicing clinicians, and owners by focusing on investigations most likely to quickly, immediately, and significantly benefit the welfare of the horse.
Contact: Nancy Collins
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