Preventing Laminitis - Dr Jennifer Stewart

Preventing laminitis in horses 101
realize is that obesity is a very unhealthy state. Not only is the
obese horse teetering on the brink of laminitis, requiring the
barest nudge to push it over the edge, if that horse does
develop laminitis the prognosis for recovery is far worse than
for a horse in ideal body condition. Although it can be a long
and frustrating process, weight reduction must be a medical
imperative in obese horses if laminitis is to be avoided.
More common, but almost as problematic because the risk
is less obvious, are horses with a BCS of 6 or 7. These overweight
horses are at increased risk for laminitis and other
health problems, yet many owners simply consider these
horses to be well cared for, pleasantly plump, or “easy keepers”;
they are unaware of the health risks, laminitis being
chief among them. It is important that we readjust our perceptions
of what a well-cared-for horse looks like. A horse
with a BCS of 6 or more is not well cared for; it is overfed and
overweight! Weight reduction must be a medical priority in
these horses if the laminitis risk is to be reduced.
Weight Reduction
The approach to weight reduction in an overweight horse is
essentially the same as it is in overweight people. It is simple,
but not necessarily easy. The key is this: calories in must be
less than calories out. In other words, the body must consume
fewer calories than it is using.
Feeding fewer calories is very important, but in many cases
it is not enough on its own. That approach does nothing to
use up the extra calories already stored as fat on the horse’s
body, unless the ration provides significantly fewer calories
than are required to meet the horse’s maintenance energy
needs. However, feeding a horse “starvation rations” (ie, less
than maintenance energy needs) sends the body into survival
mode—ie, preservation mode—which makes weight loss even
more difficult, as the preservation of energy stores becomes a
metabolic priority. Furthermore, feeding severely calorie-restricted
diets to overweight horses (especially ponies and
Miniature Horses) can cause a metabolic condition called
hyperlipemia, which can be life-threatening, and increases
the laminitis risk.
For effective and healthy weight loss, the horse must also
perform more daily activity than it has been doing. The objective
is to use up the extra calories already stored on the
body as fat. This aspect of weight management can be quite a
challenge in overweight horses that already have laminitis or
that are lame for other reasons. However, it is not impossible.
The exercise does not need to be high intensity or high impact;
simply walking the horse each day can be beneficial
(provided the horse’s medical condition allows).
Of course, the more daily exercise the horse performs, the
better for weight loss, but the horse’s current fitness and
comfort must be the guide as to how much exercise (how far
and how fast) to perform at a time. Alternatives to riding
include hand-walking (ie, leading the horse), longeing, free
schooling in a round pen or arena, ponying (ie, leading the
horse while riding another horse), driving, ground driving
(ie, long-lining from the ground), and swimming or wading.
Paddock or dry lot turnout generally is not enough, as most overweight
horses just stand around when turned out.
Grain should not be fed to overweight horses. For one
thing, they do not need the extra calories. In addition,
in some very carbohydrate-sensitive (ie, insulin-resistant)
horses, even a small amount of grain can cause metabolic
alterations that interfere with effective weight loss and laminitis
management. For the same reasons, sweet treats (eg,
those containing molasses or other sugary taste enhancers or
binding agents) and other starchy foods should be avoided.
Grass hay cubes can be a good alternative to sweet treats,
provided the hay cubes do not contain molasses or other
sweeteners, and treats are offered only occasionally and only
in small amounts.
High-fat feeds also should not be fed to overweight horses,
no matter how low their content of starch and sugars. These
feeds do not present the laminitis risk that high-carbohydrate
feeds do, but overweight horses simply do not need the extra
calories. It is stating the obvious to point out that it is counterproductive
to feed fat to a horse that needs to lose fat!
Some veterinarians and horse owners opt to “micromanage”
overweight horses by monitoring insulin resistance using
blood tests and by analyzing every component of the diet
and manipulating the NSC and mineral content accordingly.
While this detailed approach may be needed in some cases, it
is not necessary in the majority of overweight horses. Good
results can usually be achieved simply by eliminating grain
and other high-carbohydrate feeds from the diet, feeding
grass hay of moderate nutritional quality, offering a vitaminmineral
supplement appropriate for that part of the country,
restricting pasture access (as discussed in the earlier section
on pasture management), and providing some type of structured
exercise every day.
Hay Quality and Quantity
The bulk of the fructans and other NSCs in grass persists
during the haymaking process, so some grass hays may be
inappropriate to feed to overweight horses, particularly those
that already have laminitis. These tend to be the hays harvested
from improved pastures and cut fairly early in the
growth cycle of the plant (ie, hay containing few or no seedheads).
Having the hay analyzed at a forage testing laboratory
that offers measurement of NSC or NFC can identify hay that
may be best avoided or fed in limited quantities to these
horses. In general, hay that has a NSC content of less than
15% is most appropriate for these horses.
The hay should be of good overall quality (ie, clean, dry,
and free of mold, weeds, and other debris), but of only moderate
nutritional quality. Mature native or unimproved pasture,
cut after the grass has produced seedheads, is recommended.
Hay cut in the fall should be used with caution, as
cold stress before harvesting may increase the fructan content
of the grass, and thus of the hay.
For horses with little or no pasture access, hay should be
fed at a rate of approximately 2% of the horse’s ideal body
weight per day. For a horse whose ideal body weight is
around 1000 lbs, 2% of body weight means 20 lbs of hay per
day. Some horses need less than that to achieve or maintain
their ideal body weight, but the amount of hay per day should
not drop below 1% of body weight (ie, minimum of 10 lbs of
hay per 1000 lbs).
Supplements
Magnesium supplementation has become a popular tool for
managing weigh reduction and insulin resistance in horses.