DEBUNKING FEEDING MYTHS

Myths and Misconceptions: 

Sorting through science and fact versus tradition is often a difficult task
by Amy M. Gill, Ph.D.

(This article appeared in the March 15th, 2008, Issue of Thoroughbred Times. To subscribe, call 1-888-499-9090)

The misconceptions about feeding horses is a topic that is written about frequently but is worth repeating from time to time, because it appears to be a difficult one for some to grasp. When it comes to feeding horses, myths and old wives’ tales abound.

Many of the traditional methods have been passed from generation to generation of horsemen, and while some are still useful, many are out-dated and even detrimental to the daily management of the modern horse. Most of the myths that are still in existence are commonly based on a lack of understanding of nutrition and the phsyiology of a horse's digestive tract.

Fortunately, modern science and research over the past 20 or so years have helped debunk many of the myths associated with feeding horses. Regardless of being proven wrong or ineffective, many of these feeding myths are perpetuated. There are many more myths and misconcep¬tions about feeding horses than those that follow, but these are some of the most difficult ones to convince own¬ers, managers, and trainers to aban¬don. Many of the old wives’ tales continue to circulate because, as the adage “it has always been done that way” implies, change is difficult.

Here is a sampling of some misconceptions:

Bran mashes have a laxative effect on the digestive tract 

Despite being fed with good intentions, a weekly bran mash is a dramatic alteration to the daily ration and causes a disturbance in the normal population of microorganisms that reside in the hindgut. Dumping bran (a substrate or food source that the bacteria are not used to) into the system causes a sudden kill-off of some bacteria and forces overgrowth of others. This shifting bacterial population in the gut usually results in a good case of diarrhea, leading one to believe wheat bran acted as a laxative. Remember, routine feeding of the same feeds every day is the best way to avoid digestive upset in horses.

Research shows that bran does not have a laxative effect or cause a softening of the manure. A study conducted at Cornell University in which 50% wheat bran was added to a diet of hay and grain found that fecal moisture was no different between horses receiving wheat bran and those on the control diet that received no wheat bran. Bran does give the manure a bulkier appearance because the fiber in wheat bran is not very digestible. The horse is dumping a bigger pile because a lot of the wheat bran was not digested, not because it contains more water.

While wheat bran does have more fiber than corn and about the same amount of fiber as oats, it has less fiber than hay, so providing plenty of hay to the horse is the best way to keep the digestive tract full of fiber and subsequently well hydrated. The amount of dry hay the horse eats will directly influence the amount of water it drinks, which will in turn help to keep the horse properly hydrated.

Recent concerns exist over the level of starches and sugars, or soluble carbohydrates, in horse rations. We now realize it is best to minimize starch and sugar in equine diets because these two ingredients have been linked to numerous exercise, growth, and metabolic disorders. Wheat bran contains a considerable amount of soluble carbohydrate (about 30%), which is another reason it should never be suddenly added to the diet in large amounts.

With that said, there remains a place for wheat bran in a horse’s diet because it is very palatable to horses and provides energy and protein at levels similar to oats. Small amounts can be fed on a daily basis in the regular ration, but it should not be fed at a rate of more than 10% of the total diet (hay and concentrate).

The reason for this guideline is that all brans, including wheat and rice bran, contain a high percentage of phosphorus but are low in calcium. Compounding the problem is that approximately 90% of the phosphorus in bran is in a form called phytate.

Phytate interferes with calcium absorption and reduces the absorption of copper, zinc, and manganese. Feeding high levels of bran can cause severe mineral imbalances that can negatively affect bone health. Bran should be used only as an ingredient in a well-balanced and fully fortified (vitamins and minerals) ration, not as a feed.

Pellets cause choke 

Pellets do not cause choke; horses that eat too fast cause choke. When horses become overly hungry due to long periods with nothing to eat, are fed in close proximity to their herd mates, or feel threatened eating in a field, they tend to become very aggressive when eating.

Choke is a behavioral problem, not a “form of feed” problem. I have seen many horses choke on fresh grass, hay, sweet feeds, large cubes, pellets, apples, carrots, straw, shavings, and handfuls of mints. A horse that eats too aggressively and bolts its feed is most likely to choke on any food source. The key to preventing aggressive eating is to change the management of the horse. This can be done by increasing turnout or grazing time, increasing feeding frequency and giving smaller portions of feed, separating an aggressive horse from the herd when being fed, and making sure horses do not become overly hungry from spending long periods of time with nothing to eat. Feeding in a shallow trough or pan with large, smooth stones that prevent the horse from getting a large mouthful of feed also can be helpful.

Beet pulp must be soaked 

Beet pulp does not need to be soaked before it is fed. Most commercial textured feed mixes on the market today contain beet pulp as an ingredient, and these feeds are not soaked before feeding. Feeding beet pulp unsoaked to a horse does not cause it to expand in the stomach to the point of rupture due to absorption of water and does not cause choke in a horse with normal eating behavior. Beet pulp has about the same amount of dry matter as alfalfa hay and therefore soaks up a similar amount of fluid when ingested.

In most cases, if beet pulp is fed alone instead of as part of a pre-mixed feed, it is more palatable if it has been soaked.Soaked beet pulp is also a great carrier for feeding medications and supplements to horses.

Horses must have grain in their diets 

Karen Briggs, in her August 18, 2003, article titled “7 Feeding Myths Shattered” at www.horsechannel.com, says, “So what’s the advantage of grain? It supplies concentrated energy, in the form of carbohydrates, which some horses need if they’re being asked to do more work than what they would normally do in the wild. Show horses, racehorses, and nursing broodmares can all use the extra nutritional support of grain to help fuel their higher energy expenditure.

“But because the equine digestive system is poorly designed to digest large quantities of carbohydrates, there’s a limit to how much grain you can feed without risking dangerous conditions like colic and laminitis. As a rule of thumb, remember that every horse should consume between 1.5% and 3% of his body weight in total feed every day, and at least half of that should be forage, by weight.”
 
 Many argue they want to feed natural, whole grains because they believe that is best for the horse. But grain is not natural for a horse to eat, and it is difficult to digest, especially when fed in large, infrequent meals.  Where would a horse find five pounds of grain out in the wild? Grasses, leaves, twigs, bark, and dirt are natural things for a horse to eat. The problem is many horses need more calories than those types of natural feed stuffs can provide. Nowadays, beet pulp, soybean hulls, rice bran, and alfalfa meal (highly digestible fibers) have replaced a lot of the grain in the diet because they provide similar levels of energy, but as fiber, not soluble carbohydrates. Feeding good-quality, soluble fiber is a much healthier way to provide energy to the hard-working horse.
 
 There is hardly anything done with domestic horses anymore that can be considered natural. For example, confinement to a stall, low forage, high grain rations, feeding only twice or three times a day instead of grazing 18 hours daily, carrying a rider, and running at very fast speeds for distances longer than would ever be required in the wild is not natural.
 
Protein makes horses behave badly
 
This myth drives nutritionist crazy. Unfortunately, feed companies have unknowingly helped perpetuate this misconception by marketing feeds as 10%, 12%, or 14%, which seems to indicate the only important nutrient in horse feed is protein. That is what those numbers indicate -- crude protein level -- not energy or caloric density. It is overfeeeding calories that can contribute to hyperactivity and fractious behavior in horses, not protein. Also, sugar content of the feed may play an even bigger role in creating a misbehaving horse. Ingested  sugars and starches cause changes in blood sugar concentrations and, much like humans, some individual horses appear to suffer the same sensitivity to the fluctuation, while others are not bothered at all.
 
 Every day, the horse has its minimum requirement for energy, protein, vitamins, and minerals. If any are limited below the requirement, growth, milk production, and performance will also be limited. If horses are fed above the requirement, protein, fats, and carbohydrates simply become available as excess calories.
 
Therefore, if a horse is having a behavioral problem that can be linked directly to feeding (all other medical conditions must be ruled out), it is best to lower the amount of concentrate intake as a whole, not just one nutrient or another. Continue feeding as much forage as possible and add a protein, vitamin, and mineral supplement that does not contain any extra calories from carbohydrates or fats. This way, caloric intake (and sugar) is limited, which is the root cause of feeding-related excitability in horses. If the horse needs to eat more to maintain weight, use concentrates low in whole grains and with more fat and fiber. These feeds supply the same calories as high-grain feeds but keep blood sugar changes to a minimum.
 
High-protein diers cause developmen problems imn foals
 
Protein is not the cause of developmental problems in growing horses.
 
Lori K. Warren, Ph.D., explains this in a paragraph taken from her paper that appears in the Proceedings of the 2002 Alberta Horse Breeders and Owners Conference.
 
"Genetics, exercise, and nutrition all play a role in the development of healthy bones, and as a result, the same factors are also linked to the occurrence of developmental orthopedic disease (DOD) in young horses."

"Most confusion regarding DOD is related to nutrition. Mineral imbalances have been well documented as a cause of DOD. Excessive protein was blamed as a cause in the 1970s, but later studies disproved this connection. Feeding more protein than the foal needs does not increase growth rate above that achieved when the diet just meets protein requirements."

“Unfortunately, the diets of many young horses are kept quite low in protein for fear of causing developmental problems. Restricting protein will not result in improved bone
growth and can actually be harmful to the foal by decreasing feed intake, growth rate, and skeletal development. On the other hand, overfeeding energy will result in developmental
problems, particularly if protein and mineral intake are not increased at the same time. Again, the horse owner must be able to differentiate between the energy and the protein content
of the diet. For growing horses, protein and minerals must be in proportion to the energy in the diet.”

Too much starch and sugar in the diets of growing horses have been implicated as a factor in the development of orthopedic problems. High-starch feeding causes a disruption to the normal secretion of the hormones that are directly involved in cartilage maturation into subchondral bone, which may result in abnormalities. The best advice is to use feeds containing higher fat and fiber, low starch, and with the correct amount of protein, vitamins,
and minerals to help combat this problem in growing horses.

First-cutting hay is not as good as second or third cutting, etc.

This may or may not be true because the cutting has nothing to do with the factors that are important to making good hay:

• Level of fertilization of the field; 
• Amount of water available during growing season;  
• Type of plant being grown; 
• Region of the country; 
• Level of maturity when harvested; 
• Insect infestation;  
• Weed control; and  
• Sunlight 

Obviously, all these variables can change dramatically throughout the growing season. Many can be controlled, and the best hay growers do just that. For example, in this country, much of the best hay comes from the dry Western regions, where the sun is almost always shining and Mother Nature does not interfere with long rainy periods. Irrigation is used to control water application, fields are properly fertilized, and the right species of plants are grown for the region.

High yields are easy to realize under these conditions because the level of control is so great. It is only when these factors are not controlled that you get a large variation between cuttings. There are some places in California that can get ten to 14 cuttings of alfalfa hay due to the long growing season and micromanagement of the plants in the field. Under such tight regulation, variation between cuttings is minimized.

The best way to evaluate hay is not by the cutting but by judging quality and maturity at cutting, how well the hay was processed, and, most importantly, how well the hay suits the nutritional needs of the horse.

Not every horse needs the best alfalfa hay, and many do well when fed medium-quality hay.

For example, horse owners with overweight horses should look for a medium-quality, low-calorie hay, and then supplement protein, vitamins, and minerals. This way, the horse can be fed more hay instead of being restricted to a very small amount of high-calorie forage, which can ultimately lead to a crabby, hungry horse that bolts its feed. Colic is also a repercussion of inadequate fiber intake.

Feeding free choice minerals allows horses to seek what is lacking

Many horses kept in a stall or small paddock will eat anything they can find once all other food sources run out. This includes the wood holding together the stall or paddock in which they are housed. This theory of free-choice feeding of minerals or anything else other than forages, water, and salt may only be applicable to horses that are free ranging thousands of acres and cover 25 to 50 miles daily to forage on enough different feedstuffs to obtain their daily nutrient requirements, but it does not hold up for domestic horses in general.

If horses are provided forage appropriate for their stage of development or level of activity along with a well-fortified, balanced concentrate or supplement, white salt, and water, nothing else need be offered to them to eat. If the diet is balanced correctly, the horse will not be lacking in any nutrients unless there is a pathological condition that exists, in which case a veterinarian and nutritionist should be consulted.

For performance horses, it is al¬ways better to completely control intake using good-quality forages and pre-mixed, balanced concentrates formulated by a reputable feed company, rather than leave the decision making to an animal that does not know any better. It is highly unlikely horses —or people for that matter— wake up in the morning and say, “Wow, I am feeling low on manganese today, so I am going to eat more of the manganese mineral mix in my stall.” It just does not work that way.

Amy Gill, Ph.D., is an equine nutritionist and consultant who specializes in growth-, metabolic-, and exercise- related disorders. Her website is www.amymgillphd.com.

Nutrition tips

• Use white iodized salt instead of red mineral salt—there is very little difference between the two, just a lot of iron oxide in the red salt that gives it the red color. Horse diets are already loaded with plenty of iron, so it is a waste of money to buy any more iron. Also, iron
overload may be a factor in the onset of insulin resistance in some horses.

• Some feed companies are adding supplements such as glucosamine or others to their feeds. The reason this does not work is because each horse will eat a different amount of the feed, and therefore will receive varying amounts of the supplement. This can
result in the horse receiving an insufficient dose of the supplement to have a therapeutic effect. Most supplements are fed in small enough amounts that they can be easily top dressed, and this is the best way to feed them to ensure accurate dosing.

• Contrary to popular belief, it is safe for horses to drink right after exercise. Recent research has shown that horses deprived of water directly after exercise are more likely to remain in a state of dehydration. Horses tend to have a better desire to drink and replenish fluid lost in sweat soon after exercise when their thirst drive is high as compared to after they have cooled down.

• Nothing can replace good horsemanship and skills developed through years of experience. Feeding horses is an art and a science, and everyone needs to be open-minded enough
to recognize what is working and when a change is needed. Acceptance of the fact that some long-held feeding traditions may not be the soundest methods will help horses in the long run, especially as we gain more knowledge from scientific studies.

—Amy M. Gill, Ph.D.