“They can’t chew very well or they don’t actually swallow what they chew. They might be ‘quidding,’ or rolling balls of feed out of their mouth.”
Parasites—intestinal worms—are another cause. A high parasite load interrupts the equine gastrointestinal tract’s ability to absorb nutrients, Schur explains, as does the inflammatory response that the parasites cause in the gut.
“In our practice, we see a lot of horses with gastrointestinal sand accumulation, too,” Schur adds, simply due to the desert location.
Diseases can be a cause as well, and are certainly something to watch for in older horses.
“It’s not uncommon to see horses with renal [kidney] compromises, or a slight hepatitis, a mild inflammatory change in the liver,” Schur cites as examples. “You find those in all ages [of horses], but you see them more commonly in older horses.”
A standard physical exam, including checking teeth and running a fecal count, can reveal a lot. She also recommends that owners of older horses routinely have a veterinarian perform a blood chemistry panel to check for signs of oncoming disease.
“We could talk for weeks about all the additional things that can cause a horse to lose weight—tumors, gastric ulcers, enteroliths [intestinal stones],” Schur says. “It’s important for owners to be aware of them.
“However, most of the time we can address [weight loss] through nutrition.”
The Common Fix
When Schur meets a horse that is underweight, she has a methodical way of going about figuring out why. First on her list is to look at the horse’s environment.
“Sometimes it’s simple things in the environment that owners just don’t catch,” she says. “Are they alone, or in a herd? Are all the horses [in a certain setting] thin, or is it just that one? Has the pasture quality changed?
“I’ll often see an underweight horse in a pen next to an overweight horse, who manages to stick its head through the fence and eat the other horse’s hay. Or horses constantly pushed away from hay because they are no longer at the top of the pecking order.
“Those situations can really affect older horses simply because they take longer to eat.”
She also considers other environmental changes, such as activity or weather: “Are they doing more work now and need a higher caloric intake? Has the winter weather started and their metabolism needs more to keep them warm?” she asks.
Next is to look at the hay.
“A lack of continuity in hay supply and quality is a common culprit [behind weight loss], depending on where you are in the country,” Schur says. “For example, here in Las Vegas, most people don’t have the space to store enough hay to last through the winter, and they buy one or two tons, or less, at a time. If they feed a grass/ alfalfa mix, their current load might be 50/50, but the next could be 80/20. Or the quality might not be as good.”
She might recommend the hay be tested for its protein, carbohydrate or mineral content, although “that’s more common to do in the case of an over-weight horse, to make sure they aren’t getting too many non-structural carbohydrates and sugars.”
Finally comes grain. She wants to see exactly what a horse is getting, using the container’s nutritional tag to evaluate protein and fat levels, and checking the scoop size used to measure it out. As horses age, their nutritional requirements change.
Once she establishes the quality and amount fed in hay and grain, and has seen the horse’s environment, Schur often has enough information to make a specific recommendation on what to change first. It might be adding fat to the diet, or increasing the hay from 8 pounds to 10, or just changing where and how a horse is fed.
“I typically start with increasing the hay,” Schur says. “In extreme starvation cases where animal control has brought in a horse, it’s always hay first, in small frequent amounts. It’s natural to start with forage in the underweight horse.
“If we add grain, we do it slowly over a 10-day period, nothing fast. When you add grain, it changes the gastrointestinal flora in the gut, and when you do that you can get gas distension [and a risk of colic] with certain types of bacteria, especially if you add too much, too fast.
“The important thing is to reevaluate them about six weeks later,” she emphasizes. “It’s tough to look at them in just two weeks and be able to really tell if they’ve gained weight unless you put them on a scale.
“I score their body condition: Is the topline filled out? Are the hips as prominent as they were? Can I see and feel the ribs?”
Schur says a simple phone call to a veterinarian can help horse owners decide what to do initially to help a horse gain weight. Then, if the horse doesn’t improve or continues to deteriorate, the veterinarian can go further.
Schur offers three reasons she thinks are helping more horses thrive well into their aged years, like her 25-year-old Etta.
“Improved and increased dental care would have to be No. 1,” she says. “That’s the thing that’s changed the most over the past 20 years.”
Better available nutrition for senior horses is next.
“There are some really great equine senior feeds on the market now,” she says. “As horses age, they lose their teeth and are unable to graze or eat hay any longer and need a complete feed.”
Third, she says, is the overall improvement in diagnosis of underlying diseases. Veterinarians can now look for diseases in younger horses and start treatment sooner, thereby prolonging the quality and length of a horse’s life.
“When I first started practicing, I never diagnosed a Cushing’s horse unless it walked in with [obvious clinical signs such as] massive amounts of hair, a big belly, and drinking a lot,” she says. “Now, we catch them earlier due to veterinarian and client awareness.
“Age isn’t a disease,” she emphasizes. “It does require some increased management, medically, nutritionally, and exercise-wise. But it’s fun—and plausible—to keep these old guys going.”
Regardless, if your horse starts to lose a little weight at any age, Schur says it’s worth a phone call to your vet.
This article was originally published in the January 2015 issue of Western Horseman.