Horse Illustrated Magazine

As the seasons come and go, your horse’s nutritional needs will change, requiring some adjustments to his diet. Start your new year off right with a resolution to plan his annual feeding schedule. Read on for season-by-season advice, followed by a handy checklist.

Spring

As temperatures finally warm and rains bring new life to pasture grass, it’s time to assess your horse’s weight when he comes out of winter.

Some horses, usually easy keepers, actually put on weight in the winter due to decreased exercise level when temps are cold. Others tend to lose weight due to lack of grazing and burning calories to stay warm.

For the easy keepers, especially ponies and breeds with cresty necks, it’s quite possible that the high sugar content in spring grass may lead to laminitis. If your horse shows any sign of foot soreness or hardening of the crest, immediately pull him off the grass and keep him in a dry lot eating hay.

If your horse is not prone to grass founder but tends to pack on too many pounds from spring grass, consider a grazing muzzle or restricted grazing hours to allow him some enjoyment but not enough to risk his health by becoming obese.

If your horse is kept stabled in the winter and will be turned out after the green grass is already thick and lush, start with a very restricted grazing schedule and gradually increase it to reduce the chance of colic or laminitis. Begin with 30 minutes of grazing per day, increasing by 5 to 10 minutes per day until reaching at least four hours of grazing, at which point they can be considered fully adjusted to the new digestive challenges of fresh grass.

Horses kept on pasture 24/7 throughout winter and into spring will have enough time to adjust to the richness of the grass as it gradually comes in, with minimal chance of digestive upset.

Spring pasture grass is high in calories, protein and vitamins, but may be deficient in certain minerals, depending on the local soil. A trace mineral salt block is the easiest way to make up the difference. A ration balancer or mixed mineral supplement will also do the job.

If you are not fortunate enough to have access to pasture grazing and your horse has lost weight over the winter, he will probably need supplemental calories in addition to all the good-quality hay he will eat.

For high-strung types, steer clear of feeds containing grains and molasses (starch and sugars). Look for formulated feeds that contain concentrated calories in the form of high fat (at least 10 percent) and highly digestible fiber, such as beet pulp. More laid-back horses can be fed commercial grain formulas. Always follow feeding instructions on the bag, which are based on body weight and life stage/work level.

Summer

Ah, summer. The season where competitions are in full swing, daylight lasts well into the evening, and clear skies call for long trail rides and endless hours in the saddle.

This is often the point in the season when pasture grass starts drying out due to heat, not providing as much nutrition as it once did. Keep this in mind when meeting your horse’s higher calorie demands, supplementing with hay and a bagged feed (mixed grain or fat and fiber, depending on the horse).

Hydration is important all year, but is particularly so in the hottest months of summer. While horses may drink only 5 to 8 gallons of water per day in the winter, they can drink up to 25 gallons in the summer. If tanks or buckets run dry, there is a higher likelihood of impaction colic, so keeping your horse well-watered is essential to the health of his digestive tract.

Check water daily to make sure it is clean and free of debris. It must also be in a shady location or it will be too hot for horses to drink—and the same as having no water at all.

Due to increased sweating in summer, your horse will need additional salt beyond that provided by hay, grain, or pasture. Horses are excellent at self-regulating their salt intake, so loose salt in a free feeder is the best option, particularly in stalls.

If your horse is on pasture, you’ll probably find a salt block the easiest solution. Some horses may not like the brown trace-mineral blocks, so plain white blocks are available. Put out at least two per pasture so the horses at the bottom of the pecking order are allowed to access one.

Himalayan and other types of salt are available as well, although horses may either eat the whole block at once or avoid it altogether. Whatever type you choose, make sure your horse will use it.

Electrolytes provide another supplemental form of sodium as well as potassium. They are generally only needed for horses that are subject to extreme exercise and sweating in hot, humid conditions.

They can be mixed with feed after exercise or dissolved in water. If dissolving in a bucket, always offer a separate bucket of plain water to let the horse regulate his intake.

Fall

If your horse tends to be on the thin side, the time to put weight on him is before winter really sets in, as it is much more difficult for horses to gain weight once they’re cold.

Ribs should be easily felt, but not seen. If you can see ribs, you’ve got some work to do this fall. Add an extra 5 pounds of hay per day to put 50 pounds on your horse in 50 days, or 2 to 3 pounds more of a bagged feed per day (since calories are more concentrated). Again, stick to higher fat/lower starch and sugar concentrates if your horse is excitable or has a condition such as insulin resistance.

Pasture grass usually has another cycle of growth in the fall as temperatures cool and rains return. However, cool or cold evenings can increase fructan content in the grass, possibly triggering a bout of founder in susceptible horses. It’s best to keep them off the pasture and back in the dry lot this time of year. For hard keepers, this is a good opportunity to allow 24/7 grazing to gain weight before winter.

If your pastures have taken a beating through the summer, it’s best to pull horses off them now before they get completely decimated going into winter.

Winter

As horses switch from a diet of some pasture to mostly hay, keep in mind that hay loses vitamin content relative to fresh grass. To keep the diet balanced for vitamin content, feed either a ration balancer, vitamin/mineral supplement, or enough commercial feed to meet all requirements (see bag tag to determine how much that is).

If your horse puts weight on in the fall and grows his natural winter coat, the critical ambient temperature—the temperature below which he must burn extra calories just to stay warm—is 15 to 30 degrees Fahrenheit. Of course, this number may vary a bit depending on breed, health, and acclimatization to the local weather.

For every 10-degree drop below critical temperature, your horse will require an extra 15 to 20 percent more food. For example, a 1,000-pound horse eating 2 percent of his body weight in hay (20 pounds) would need to eat at least 3 more pounds for a 10-degree drop in temperatures.

Grass hay is best for easy keepers, while a grass/alfalfa mix and possibly supplemental bagged feed (grain mix or fat/fiber mix) is better for hard keepers. Horses kept in heavy work should get fed more like hard keepers. Don’t forget to keep salt available, since horses can sweat quite a bit on warm days or during heavy exercise in their winter coats.

If you body clip or blanket, critical temperature can vary quite a bit. Keep an eye on body condition throughout the winter to make sure your horse’s weight stays on target (you can feel ribs but not see them).

You may have heard that horses should be fed corn in the winter because it’s a “hot feed,” but this is an old wives’ tale. Although corn contains 45 percent more calories per same size scoop as oats, oats actually produce more heat in the body due to their higher fiber content.

Fiber digestion in the horse’s hindgut works like a wood stove, giving off heat as microbes break down the plant matter. For this reason, feeding extra hay (as much as your horse will eat) is always a good way to keep weight on and keep him warm if you live in a cold climate.

If he still tends to get thin in the winter but your vet finds him healthy otherwise, you can start increasing the concentrate portion of his diet with a bagged feed. If the feed is heavy on grain, don’t feed more than 5 pounds at a time, as this is all the small intestine is able to process. Break up into two or three feedings per day if needed.

Another old wives’ tale is that bran mashes will work as an anti-colic laxative or keep your horse warm. Many also believe it helps add hydration, which it does to a small degree, but not significantly. The only benefit of a bran mash is in the horse owner’s mind (sorry!). Wheat bran actually contains less fiber than hay, and is similar to feeding a grain. It is also unbalanced for nutrients, so feed sparingly if you must.

Extra stall time in winter can be extremely stressful for horses, leading to ulcers and/or a depressed immune system. Keep hay available as much as possible to buffer stomach acid; horses on pasture spend at least 18 hours per day eating, and a similar amount of time if kept stabled with hay. You might also consider a vitamin E supplement for the immune system, but skip the selenium to avoid toxicity issues.

For seniors, long-stem hay can be a problem for worn or missing teeth, leading to weight loss, particularly in winter when pasture isn’t available. Instead, feed soaked hay cubes or hay pellets in the same amount per day as hay; weigh while dry for accuracy.

Drinking is just as important during the winter, so be sure to break ice on troughs and buckets at least twice per day. There are various options to keep your horse’s water from freezing in the winter, including stock tank heaters, automatic waterers with pipes installed below the frost line, and insulated or heated buckets. If you heat your water supply, keep it around 45 to 65 degrees, checking frequently that all cords are safe from rodents or curious horse teeth. You can also add 1 to 2 ounces of salt to the feed to stimulate thirst for horses reluctant to drink enough in the winter.

Adjusting your horse’s diet is a year-round endeavor, so make sure to take into account seasonal challenges when selecting a feeding plan.

Seasonal Feeding Checklist

Spring

• Assess whether your horse needs to gain or lose weight
• Keep founder-prone horses and ponies off spring grass
• Use grazing muzzles on other easy keepers
• Gradually allow horses that have been stalled time to adjust to the rich grass
• Put out trace mineral salt blocks to round out an all-pasture diet
• Horses without access to good pasture that need to gain weight will need increased hay amounts and a commercial concentrate feed, either mixed grain formula or fat & fiber formula depending on their needs

Summer

• Monitor your horse’s weight with increased exercise and decreasing pasture quality
• Make sure buckets and troughs are filled with clean water at all times to meet higher demand and prevent impaction colic
• Water must be kept out of the sun or it will be too hot to drink
• Always provide a source of salt, either loose in a free feeder or block form
• Also supplement with electrolytes in extremely hot/humid climates or for horses in heavy work that sweat excessively
• Order enough hay for the winter during one of the summer cuttings; you’ll get the best price and avoid shortages that occur when the growing season ends

Fall

• Strive to put weight on harder keepers before cold weather sets in
• Feeding an extra 5 pounds of hay per day will result in gain of 50 lbs in 50 days for the average-size horse (1,000 lbs)
• Add commercial concentrate feed (mixed grain or fat & fiber) for faster weight gain
• Fructan levels in grass can spike again in fall, so be careful if allowing founder-prone horses and ponies any grazing time
• Pull horses off small pastures before winter sets in to preserve roots and thatch for future seasons

Winter

• Keep diet balanced with a ration balancer or vitamin supplement if not feeding a commercial concentrate
• For every 10-degree drop below “critical temperature” (15-30 degrees F), horses need an extra 15-20% more food
• Feed harder keepers hay that is a grass/alfalfa mix to boost calories
• If body clipping and/or blanketing, your horse may need more or fewer calories depending on his situation
• Bran mashes do not work as a laxative or keep your horse warm. If you want to feed one, do so sparingly to avoid digestive upset.
• More time in the stall can lead to stress and ulcers, so it’s especially important to keep hay available to buffer stomach acids
• Seniors with worn teeth may need soaked need hay cubes or hay pellets as their primary feed when grazing dries up
• Make sure unfrozen water is available at all times, breaking up ice twice a day or using trough heaters

Holly Caccamise has a Master’s degree in animal science with a specialization in equine nutrition.

This article originally appeared in the January 2018 issue of Horse Illustrated magazine. Click here to subscribe!