by Marcia King
There are some food needs that just can’t be argued against:
1. Humans + popcorn + cola at movies.
2. Women + chocolate at anytime.
3. Horses + natural forage at all times.
These combinations aren’t exclusively important for their nutritional values – the first two are mostly “zip” when it comes to addressing anything involving the required daily allowance – but they can sure make us feel satisfied when we get them, and downright surly when we’re deprived of their pleasures. Similar with horses and forage.
Yes, forage meets the nutritional and physical needs of a horse, but so do grains and concentrates. But natural forage satisfies some sort of important and inherent need as well, and deprivation of same can lead to a grumpy horse with some nasty vices.
There are a number of reasons, though, why it may be necessary to remove a horse from natural forage. Beware: Keeping the hay- or pasture-deprived horse happy is no easy task.
Au Natural
Although concentrates and grains can provide a nutritionally complete and balanced diet, under normal conditions forage should be the mainstay of the equine diet.
For starts, forage addresses physiological needs that no other food source can. Explains Ann Swinker Ph.D., Extension Horse Specialist, Associate Professor of Dairy and Animal Science, Pennsylvania State University, “Horses are herbivores in nature and require roughage in small meals throughout the day in their diets. This is how their digestive systems are intended to function.”
Forage is a required source of fibre, Dr. Swinker states. “Usable or digestible fibre is necessary as a source of energy by microorganisms in the horse’s cecum and large intestine and provides a source of dietary energy for the horse.”
Indigestible fibre, which is low in all non-forage feeds, is also a necessary component of the equine diet. “Indigestible fibre is required for the maintenance of normal gastrointestinal pH, motility, and function,” Dr. Swinker says.
“Indigestible fibre also helps prevent too rapid an intake of readily digested carbohydrates, which are high in cereal grains. Carbohydrates taken in too fast or in excess will cause diarrhea, colic, and acute laminitis.
“Therefore, a certain amount of fibre that can only be provided by feeding forage or by-products that are high in fibre such as hulls are required by the horse for normal intestinal function and by microbial organisms. Both are necessary for the horse’s health and well-being.”
Secondly, there is some sort of behavioural component involved with hours-long chewing. Horses denied access to forage often develop unpleasant habits.
“We know there is a big link between stereotypical behaviour – what people used to call vices – and forage intake,” says Nancy Kate Diehl, MS, VMD, Assistant Professor of Equine Science, Department of Dairy and Animal Science, Pennsylvania State University.
“Most literature, from both research reports as well as anecdotal and nonscientific observations, note that horses that don’t get enough forage tend to develop stereotypical behaviours, particularly cribbing.
Although cribbing is extremely refractory to almost any treatment, cribbing and other stereotypical behaviours like weaving and stall walking can be significantly reduced if you take the horses off of grain and put them on forages.”
Although she cautions that her observation is subjective, Dr. Diehl noted that “hot-house” show horses kept on a relatively high grain, low forage ration that were stalled most of the time often appeared to lose spark and develop a very sour and sullen attitude.
It’s not a matter of an incomplete diet. “To the best of our knowledge, a complete pelleted, extruded or textured feed is designed to meet nutritional needs in terms of protein, vitamins, minerals, and caloric intake,” Sarah Ralston, VMD, PhD, Diplomate American College of Veterinary Nutrition, Associate Professor in the Department of Animal Science, Rutgers University, says.
“But I haven’t seen any commercial concentrate feeds that seem to be able to satisfy the apparent need for chew time.
“If you feed a horse a complete pelleted or extruded feed without any forage, even if you spread it across three or four feedings a day and are meeting all of his nutritional needs, the horse can look great, but will still turn into a termite.
“We did studies here at Rutgers where we fed them only grain plus cubed hay,” Dr. Ralston continues. “The problem was they could consume their entire allotment of feed in less than three hours a day.
“If you visit our barn here you’ll see the effects of that! Even though they were otherwise very healthy, they seemed to need to chew. I’m not sure whether it’s driven by their gastrointestinal cues or an oral gratification issue.”
One theory for the behavioural change is that horses that eat constantly, as nature intended, maintain a higher gastric pH, thereby keeping their stomach buffered and thus less likely to develop gastric ulcers.
“By cribbing, it may be that horses are producing saliva which buffers the stomach contents,” says Dr. Diehl. “There may be a physiological pain relief effect.”
Or, it could be that nature program horses to be chewing machines. Says Andrew McLean, BSc., Diploma of Ed, PhD candidate, Director Australian Equine Behaviour Centre, Victoria, Australia, “My thoughts on this are since the horse has evolved to graze for 16-plus hours a day and a lot of brain circuitry is therefore devoted to this activity, his mental welfare is compromised in restricting his grazing.”
Reasons to Restrict
Regardless of a horse’s physiological or psychological need to chew for long hours, sometimes circumstances necessitate that pasture or hay be limited.
• Unsafe pasture. “One reason to limit exposure to pasture is if a mycotoxin is suspected to be on the pasture,” says Bonnie S. Barr, VMD, internal medicine, Rood and Riddle Equine Hospital, Lexington, Kentucky. Other kinds of grass contamination or recently applied herbicides or fertilizers can also make grass unsafe.
• Overgrazing. Some pastures have difficulty supporting their herds if grazing is unrestricted. Says Dr. Barr, “Some people restrict access to their pasture if pasture is limited, in order to keep the pasture green and the weeds from taking over, which may occur if the pasture is overgrazed.”
• Respiratory problems. “Horses with chronic obstructive pulmonary disease, if kept indoors, are exposed to allergens present in the hay and bedding that could cause problems,” Dr. Barr says. “On the other hand, there is a summer-associated obstructive pulmonary disease that occurs as a result of exposure to specific pastures during the summer months.”
• Allergies. “Some horses are allergic to molds, spores, or fungi on certain hays,” states Dr. Swinker. “They may also be exposed to endophytes or endotoxins in the hay.”
• Pregnancy. “During their last trimester, pregnant mares should be restricted from fescue hay or grass because of endophyte, unless the fescue hay or pasture is endophyte free,” Dr. Swinker says. “Infested fescue consumed during this period may cause abortion, prolonged gestation, a thickened placenta resulting in difficult foaling, a decrease or absence of milk production, a weak foal or maybe death of the foal.”
• Founder. “Horses prone to founder should be restricted from straight alfalfa,” warns Dr. Barr. “You also have to worry about lush grass and laminitis.”
• Bad teeth. “If the horse does not have adequate dentition or if his teeth are really bad and he can’t chew hay, then long-stemmed hay may need to be restricted,” Dr. Ralston says. Poorly chewed hay can lead can lead choke or impaction colic, in some cases.
• Surgery. “Pre-surgery, forage should be limited to reduce fecal output in cases of rectal rear surgery or rectovaginal repair,” Dr. Barr states. “In cases of colic surgery, forages may be restricted post-surgically for a few days.”
• Obesity. Some horses get fat on pasture, thus requiring reduced grazing time.
• Availability, affordability. “Some people just can’t get good quality hay,” Dr. Ralston points out, “or it is very expensive, so they restrict hay for economic reasons.” Adds Dr. Swinker, “During a drought where no long-stemmed hay is available, people must feed pellets or alternative forage sources.”
• Use. “Racehorse people tend to restrict hay,” says Dr. Ralston, “ because hay is a bulkier feed and adds weight to the horse. Every ounce counts in a one-mile race.”
Coping With the Crazies
Whatever the reasons, limiting pasture and hay is the easy part: keep the horse stalled, don’t feed him hay. Turn him out in a dry paddock, don’t feed him hay. Reduce pasture time, or eliminate it all together. Muzzle him to keep him from ingesting sand in a sandy paddock or grass in the pasture.
The hard part is dealing with the effects of forage deprivation. Says McLean, “We are talking here about a neurologically-wired response that has been thwarted. It’s not a matter of soothing him but rather one of fulfilling this hard-wired drive in some other way, like an Edinburgh Ball (a tight, heavy ball of hall that takes a long time to eat) or providing plenty of low grade roughage.
“It is a matter of fulfilling a very basic drive that is millions of years old in its evolution. The horse does not have insight into his own instincts, like you or I do, so he cannot understand his predicament.”
To help deal with those difficulties, Dr. Ralston suggests spreading out what hay can be fed over three or four feedings, offering just a little bit at frequent intervals. “That helps relieve the boredom,” she says.
Hay substitutes may help. “Use the closest thing to forage that you can,” recommends Dr. Ralston. “Chopped hay products, hay cubes, and beet pulp do a good job of providing some form of fibre to the horse’s gastrointestinal tract.
“However, they’re so easily digested and consumed that you’re going to potentially run into some adverse effects, even so, such as wood chewing and, in some horses, choke.”
Gas colic due to bypassing digestion in the small intestine, resulting in an over-fermentation in the large colon and small cecum, is another possible side effect, Dr. Barr notes.
Dr. Barr cautions that beet pulp should not be fed as sole source of nutrition because it does not contain the proper balance of nutrients, and that wheat bran, which is also a good source of fibre, should not be use for long periods or in large quantities because bran is extremely high in phosphorous and will cause calcium/phosphorus imbalances.” (An imbalance in the calcium/phosphorus ratio is likely and will adversely affect bone strength, Dr. Ralston emphasizes.)
An option for horses with chronic obstructive pulmonary disease is hypoallergenic hay. “I know several people who have their horses on it because of COPD and it seems to work,” says Dr. Barr.
Allowing turn out in a paddock and giving them exercise may help. “Normal movement and exercise is needed for normal intestinal and digestive function,” says Dr. Swinker. Ditto for physical and mental stimulation: Movement and exercise is needed for the horse to maintain its health and sanity, Dr. Swinker says. “Keep on a schedule. Do not lay off riding, exercise, or work.”
Toys generally do not offer long-term stimulation. “Toys don’t really alleviate the problem,” says Dr. Diehl. “They’re like children’s Christmas toys: most of the time they sort of get forgotten. Toys don’t replace forages.” She adds, “Exercise doesn’t really replace forage, either. Nothing really replaces forage.”
Bottom line, non-forage diets should only be fed under the direction of a veterinarian and due to a major health problem, Dr. Swinker says.
“Each class of horse requires a certain amount of fibre and roughage in their diets. Some horses will reject quite palatable feed and start eating poor hay or bedding.”
If you and your horse are unfortunate where your horse has to go the non-forage route, per your veterinarian’s approval try your best to satisfy him via substitutes, spreading out feeding times, providing products that take a long time to eat, and utilizing physical exercise to help keep your horse occupied.
If your horse gets grumpy or starts displaying stereotypical behaviours, try to remain patient and understanding, grit your teeth, and reach for a chocolate bar.
