Hay for Horse Health

Horses with conditions such as muscle or metabolic disease might have special hay needs to stay healthy.

Horses with conditions such as muscle or metabolic disease might have special hay needs to stay healthy.

Hay. It’s an essential part of a horse’s diet, fueling the equine body and equipping it for optimal function with energy, protein, vitamins, and minerals. In fact, we know that for many horses, and especially during certain times of the year, hay becomes the most critical part of the forage diet, which is why we work so hard (and spend so much!) to find and secure quality hay for our horses. It’s also why we’re always scrutinizing, shaking, and smelling flakes of hay before feeding them to our horses.

But great hay can only go so far for horses with certain health conditions—it can even harm them if certain nutrient levels are too high or low. So, what and how much hay do we feed our horses with metabolic or other conditions that diet impacts?

The Healthy Horse’s Hay Needs

To get started, we need to review how we build the normal, healthy horse’s hay ration. The average horse should consume around 2% of his body weight per day in forage (including grass), but New Jersey equine practitioner and consultant for the Veterinary Information Network Kate Hepworth-Warren, DVM, Dipl. ACVIM, maintains that there is no one-size-fits-all hay ration for a healthy horse.

“You have some horses that are easy keepers that do fine with grass hay alone,” she says. “All horses need hay. What type and what you supplement with will depend on the type of horse.”

For example, “some Thoroughbreds may need to be fed 2% of their body weight,” she continues. “They may even need up to 3%. And they probably need grain and a diet balancer.”  

The hard-keeping Thoroughbred, says Hepworth-Warren, might need some alfalfa mixed with grass hay to get enough protein. “Whereas a similar-sized Quarter Horse, like my porky mare, may need only grass hay and never any grain.”

The authors of the textbook Equine Internal Medicine (by Reed, Bayly, and Sellon) note that plant leaves contain higher nonstructural carbohydrate (sugars and starches) and protein levels than stems, so hays with a high leaf-to-stem ratio generally have a higher nutritional value.

But, as you might suspect, higher nutritional value isn’t a good idea for every horse (Here’s looking at you, rotund little pony!). Different levels of hay nutrition might be more appropriate for the changing needs of horses with a few specific diseases.

Hyperkalemic Periodic Paralysis (HYPP)

Dietary management is critical to minimizing clinical signs in horses (primarily Quarter Horses) affected by the genetic muscle disorder HYPP.

These horses have a mutation of the skeletal muscle sodium channel gene, which causes the muscle cells to release potassium and also causes muscle hyperexcitability. Signs of clinical HYPP can range from muscle tremors to paralysis and even death.

Hepworth-Warren recommends avoiding high-potassium hays, such as alfalfa, and feeds containing molasses when feeding horses with the HYPP mutation. She stresses the importance of keeping these horses on a consistent diet with plenty of grass turnout. “Most HYPP horses are easy keepers anyway,” she says. “Any feed change has to be very, very gradual. Don’t run out of hay and change feeds overnight.”

Low-potassium hays, such as late-cut grass hay (e.g., timothy, Bermuda), are better choices for these horses.

Equine Metabolic Syndrome (EMS)

Horses with this disorder are prone to collecting fat in specific areas of the body (typically the crest, tailhead, shoulder, udder, or sheath) or just generally appearing obese. These horses typically also have abnormal blood insulin responses to carbohydrate or sugar intake (insulin resistance, meaning they have lost sensitivity to insulin that the pancreas releases, which makes it harder for the fat, muscle, and liver cells to transport glucose out of the bloodstream and store it as glycogen) and are predisposed to laminitis.

Hepworth-Warren points out that not all horses with EMS are obese. Knowing these animals’ insulin status is important, because it can indicate whether they will be highly sensitive to carbohydrates, even if they don’t look like classic EMS cases. She suggests that owners of EMS horses “feed hay that looks to be of poor quality but isn’t moldy. Those horses also should not have alfalfa and don’t need the lush green hay that we think looks the tastiest. These may only need to be fed 1.5% of their body weight in hay to maintain a good weight.”  

Divvy up theses horses’ hay in slow-feed or similar haynets to keep them foraging, essentially helping their reduced ration last longer. And because lower-quality hay might not meet all their nutritional needs, you might need to add a low-calorie ration balancer or a vitamin and mineral supplement to their diet.

Soak hay to reduce its carbohydrate content if your horse has EMS or PSSM.

While “weighing hay is something people don’t like to do,” says Hepworth-Warren, she does suggest owners purchase a small luggage scale to weigh each bale of hay. And clearly, she says, grain is a no-no for these horses.

Many people, including Hepworth-Warren, advocate soaking hay to reduce its carbohydrate (starch) content, but the 2010 American College of Veterinary Internal Medicine consensus statement on equine metabolic syndrome states that “a recent study demonstrated that results vary markedly among different hay samples, so this strategy cannot be relied upon to completely address the problem of high water-soluble carbohydrate concentrations in the hay that is being fed to a horse or pony with EMS.”

In other words, you can’t just soak the hay and call it done. It’s a good idea, then, to have a laboratory analyze your EMS horse’s hay for carbohydrate content.

Polysaccharide Storage Myopathy (PSSM)

Like horses with EMS, these horses, says Hepworth-Warren, “can’t process carbs as well. You want to feed them similar to an EMS horse.”

These horses have a defect in the breakdown and processing of carbohydrates and accumulate polysaccharides in the muscle, making them prone to rhabdomyolysis (tying-up) and exercise intolerance. In addition to regular turnout and exercise, these horses do best on a high-fat (13%), low-starch (less than 10%) diet.   

Hepworth-Warren suggests supplementing a diet of good-quality, low- to moderate-quality grass hay and low-starch grain with a fat source such as corn oil or commercial fat supplements (to make sure the horse is still getting enough calories). And, again, “Soaking hay can remove a lot of starches,”
she adds.  

Equine Gastric Ulcer Syndrome

All ages and breeds of horses can develop ulcers in their esophagus, stomach, and small intestine.

The authors of a 2009 study on the dietary management of equine gastric ulcer syndrome note multiple risk factors, including intense exercise, intermittent feeding, stall confinement, and high-concentrate (grain-heavy) diets.  

For horses affected with gastric ulcers, the key, says Hepworth-Warren, is “keeping hay in front of them all the time or, better yet, keeping them turned out on pasture. Some research has shown if there is a long period of fasting (as seen with once or twice daily meal feeding), these horses have more acid buildup (in the stomach).”  

These study authors (Andrews et al.) suggest alfalfa hay “may have a protective and antiulcer effect in horses.” Hepworth-Warren, however, says the jury is still out on this. “Some older research suggests alfalfa, which is higher in calcium and protein, can buffer the stomach acid,” she says. “There is always ongoing research into gastric ulcers, and the way feed affects them depends on the type of ulcers that the horse has.”

Other Conditions

Hepworth-Warren mentions a few other special-needs cases when it comes to feeding (or not feeding) hay. For horses with recurrent choke she suggests soaking hay to soften it before feeding. She also suggests soaking to minimize hay dust for horses with recurrent airway obstruction (RAO, heaves).

She notes that Miniature Horses “are the exception to the ‘all horses need hay’ rule because they like to develop small colon impactions.” However, she adds, 24/7 pasture grass is risky in Minis because “they are always on the edge of foundering.” For Minis prone to impaction, she recommends a low-starch pelleted feed. Some can tolerate hay very well, whereas others might need to be on a complete feed.

Take-Home Message

When purchasing hay, says Hepworth-Warren, “the main thing is thinking about your particular horse. I don’t know if the cutting necessarily makes a ton of difference. You want good-quality hay.”

While color is not always an indicator of quality, she says, it is important to make sure the hay is “palatable and not moldy and not overly stemmy.”

Above all, she says, “People need to know they can’t feed every single horse the same. Measure appropriately—a flake is not a flake is not a flake.”  

While many horses do well on an all-hay diet, the composition of that diet must meet each horse’s needs. When in doubt, work with your veterinarian or nutritionist and send your hay in for an analysis. And, when making any feed changes, do so gradually.  


Christy Corp-Minamiji, DVM, practices large animal medicine in Northern California, with particular interests in equine wound management and geriatric equine care. She and her husband have three children, and she writes fiction and creative nonfiction in her spare time.

Keeping Water Troughs Thawed With or Without a Heater

Our equine nutritionist offers tips and asks for your input on dealing with ice in horse watering tanks.

keeping water troughs thawed

Q.Winter has barely started, and I’m already tired of breaking ice in my horses’ water trough. Is there anything I can do to help stop the water from freezing other than some kind of water heater?

A.We all know how important it is for our horses to have ready access to water, but this can pose challenges when temperatures fall below freezing and you’re unable to use a water heater. It’s a lot of, literally, digit-numbing work and sometimes near impossible to break the ice when temperatures fall. There are some things you can try that might help. However, keep in mind that many of these are less effective as temperatures decrease.

1. Locate your trough for sun exposure.

Place your trough in such a way that it receives as much full sun as possible. Many northern areas might not see much winter sun, but placing the tank in a south-facing area will increase the odds of as much sunlight as possible during daylight hours. Also, consider whether a shaded area is a good idea. While some shade, for example the overhang of a building, might offer some protection from cold overnight, it likely means less sun exposure during the day. If you live in an area where the trough will freeze whether it is under some kind of shade or not, I would place it where it will get the most daytime sunlight.

2. Insulate your trough.

Obviously this helps keep the exterior cold out and the interior warmth of the water in. Styrofoam board and/or foil covered insulation works well and can be wrapped around the outside of the trough. What works even better is putting one trough inside another, with a gap of a couple of inches all the way around. Then, place insulation on the bottom between the two troughs and around the outside of the interior trough. Finally, fill any gaps with spray insulation that sets hard. You can also build a plywood box, line it with insulation, and put your trough inside it.

Ideally, the top of the trough also needs to be insulated with just enough surface exposed for the horses to drink. A plywood lid with the underside covered in insulation works well.

Online resources for those living off the grid have useful information about how to build insulated troughs and use passive solar heating to reduce freezing. Some report that this is an effective method down to -10° Fahrenheit.

3. Place a float in the trough.

Floating something in the trough helps in a couple of ways. First, it keeps the surface of the water moving as it bobs about, making it more difficult to freeze. Second, if the horses learn to depress the floating object, it will expose an open area in the ice so they can drink. I have seen this done with soccer balls, but another tactic is to fill an empty two-liter soda bottle two-thirds full with water and 1 to 2 cups of salt dissolved and seal tightly. There is enough air in the bottle for it to float, and salt water freezes at a lower temperature than the water in the trough, so the water keeps moving. These methods receive mixed reviews. Some people swear by them, while others find they don’t work at all.

4. Bury your trough.

If your ground is frozen it is likely too late this year, but digging a hole for your trough and sinking it into the ground might help by insulating it. Again, this is going to depend on where you live and how deep down your ground freezes. I read one account from someone living in North Dakota who used a fence post auger to dig a 12-inch hole several feet deep under their water trough. Apparently the heat rising from deep within the earth helped prevent the trough from freezing.

5. Heat your trough.

Ultimately, you might need to break down and heat your trough. There are several options, including battery, electric, or propane heaters. But before trying these you could try putting manure under your trough. Composting manure generates heat, and the thinking is that if you have a several-inches-thick layer of manure under your trough, as it breaks down it will help warm the trough.

If you decide to use a battery, electric, or propane water-heating element, be sure to install it safely. Follow the manufacturer’s instructions, be sure to keep all cables out of the way, and have no connections near water. Definitely consider having a lid on the trough, as it will not only help keep the heat in but also help prevent your horse from accessing the heating element.

Actively heating your trough in combination with one or more of the above ideas will likely reduce energy costs.

Regardless of what methods you decide to try, you should still work on the assumption that you will need to check water at least twice a day to ensure availability during cold weather.

If you have creative ideas on how to help prevent troughs and buckets freezing, we’d love to read about them in the comments below.


Clair Thunes, PhD, is an equine nutritionist who owns Summit Equine Nutrition, based in Gilbert, Arizona. She works as a consultant with owners/trainers and veterinarians across the United States and globally to take the guesswork out of feeding horses and provides services to select companies. As a nutritionist she works with all equids, from WEG competitors to Miniature donkeys and everything in between. Born in England, she earned her undergraduate degree at Edinburgh University, in Scotland, and her master’s and doctorate in nutrition at the University of California, Davis. Growing up, she competed in a wide array of disciplines and was an active member of the U.K. Pony Club. Today, she serves as the district commissioner for the Salt River Pony Club.




TAKE NOTICE that the Annual General Meeting of the BC Thoroughbreds Owners & Breedersí Association will be held:

Time:  Commencing at 12:30 pm
Sunday, October 27, 2019
Place:  Hastings Racecourse -Old Slots Floor Meeting Room

The main purpose of the meeting is for the following:

1. To receive the annual reports of the Society;
2. To approve the appointment of the Auditor for the 2019 fiscal year;
3. To transact such business that may properly come before the Annual General Meeting.

DATED THIS 4th day of October, 2019.


Note:  The 2018 BCTOBA Financial Statements and Minutes of the October 8, 2018 Annual General
Meeting will be available at the meeting.

BC Thoroughbred Owners & Breeders Association #7 ñ 5492 Production Blvd., Surrey BC  V3S 8P5
Telephone: 604-534-0145  www.bctoba.com


(Entries Close on Wednesday, Oct 16th)


Purse $12,000. (Plus up to $1,800 in Participation Money)(Plus up to $3,000 for BC Breds) For Maidens, Three Years Old and Upward.

Weight 119 lbs. Older 124 lbs.

CLAIMING PRICE $8,000, For Each $1,000 To $6,000 3 lbs.



Purse $14,000. (Plus up to $1,800 in Participation Money) (Plus up to $3,750 for BC Breds) For Maidens, Two Years Old.

Weight 119 lbs.

CLAIMING PRICE $16,000, For Each $1,750 To $12,500 3 lbs.



Purse $11,500. (Plus up to $1,800 in Participation Money)(Plus up to $2,875 for BC Breds) For Three Year Olds and Upward Which Have Not Won A Race Since September 19 or Which Have Never Won Four Races.

Weight 119 lbs. Older 124 lbs.

Non-winners Of A Race Since September 19 2 lbs.  A Race Since August 19 4 lbs.

CLAIMING PRICE $6,250, For Each $625 To $5,000 3 lbs. (Races Where Entered For $4,000 Or Less Not Considered In Eligibility)



Purse $14,000. (Plus up to $2,100 in Participation Money) (Plus up to $3,500 for BC Breds) For Three Year Olds and Upward.

Three Year Olds 119 lbs. Older 124 lbs.

Non-winners Of A Race At A Mile Or Over Since September 19 2 lbs.  Such A Race Since August 19 4 lbs.

CLAIMING PRICE $12,500, For Each $1,250 To $10,000 3 lbs. (Races Where Entered For $8,000 Or Less Not Considered For Allowances)



Purse $11,500. (Plus up to $1,800 in Participation Money)(Plus up to  $2,875 for BC Breds) For Three Year Olds and Upward Which Have Never Won Three Races.

Three Year Olds 119 lbs. Older 124 lbs.

Non-winners Of A Race Since September 19 2 lbs. A Race Since August 19 4 lbs.

CLAIMING PRICE $8,000, For Each $1,000 To $6,000 3 lbs.



Purse $20,000. For Maidens, Three Years Old and Upward.

Three Year Olds 119 lbs. Older 124 lbs.

CLAIMING PRICE $50,000, For Each $5,000 To $40,000 3 lbs.



Turf Paradise Daily Results and Activity


Tuesday, October 15
Race# Race Type Purse
Race 1 Starter Allowance – $4,000 $8,200 Overnight Overnight
Race 2 Claiming – $10,000 $8,500 Overnight Overnight
Race 3 Maiden Optional Claiming – $30,000 $12,000 Overnight Overnight
Race 4 Claiming – $10,000 $8,000 Overnight Overnight
Race 5 Waiver Claiming – $3,000 $7,000 Overnight Overnight
Race 6 Allowance Optional Claiming – $12,500 $13,500 Overnight Overnight
Race 7 Claiming – $5,000 $7,500 Overnight Overnight
Race 8 Allowance Optional Claiming – $20,000 $13,000 Overnight Overnight

Early Entries

Sunday, October 20 Overnight
Race# Race Type Purse
Race 1 Trials $3,000
Race 2 Trials $3,000
Race 3 Allowance $5,000
Race 4 Allowance Optional Claiming – $15,000 $13,000
Race 5 Claiming – $3,000 $7,000
Race 6 Claiming – $3,000 $7,000
Race 7 Allowance Optional Claiming – $30,000 $18,000
Race 8 Claiming – $3,500 $7,000

Final Entries

Saturday, October 19
Race# Race Type Purse
Race 1 Maiden Claiming – $7,500 $6,600
Race 2 Maiden Optional Claiming – $30,000 $12,000
Race 3 Claiming – $3,500 $7,000
Race 4 Claiming – $8,500 $8,500
Race 5 Starter Optional Claiming – $15,000 $13,000
Race 6 Claiming – $3,000 $7,000
Race 7 Princess of Palms S. $25,000
Race 8 Allowance Optional Claiming – $30,000 $18,000

Golden Gate Daily Results and Activity

Early Entries

Friday, October 18 Overnight
Race# Race Type Purse
Race 1 Maiden Claiming – $8,000 $10,500
Race 2 Claiming – $3,200 $10,000
Race 3 Maiden Claiming – $25,000 $14,000
Race 4 Claiming – $5,000 $11,500
Race 5 Claiming – $12,500 $17,000
Race 6 Starter Allowance – $50,000 $19,000
Race 7 Allowance $31,000
Race 8 Claiming – $4,000 $10,400

Final Entries

Thursday, October 17
Race# Race Type Purse
Race 1 Maiden Claiming – $8,000 $10,500
Race 2 Claiming – $5,000 $11,500
Race 3 Claiming – $6,250 $11,000
Race 4 Starter Allowance – $50,000 $19,000
Race 5 Maiden Claiming – $12,500 $11,000
Race 6 Claiming – $12,500 $17,000
Race 7 Maiden Claiming – $25,000 $14,000