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METABOL IC SYNDROME
Equine
metabolic syndrome
Equine metabolic syndrome (EMS) is a condition which vets have only recently become
aware of. It is usually associated with horses and ponies that suffer from laminitis. It has
similarities to Type 2 diabetes in humans. EMS in natural living, native ponies is normal: it
allows them to put on weight in the summer and then use these fat reserves in the winter
months. Our domestication of horses and ponies – rugging up and feeding them all year
round – interferes with this natural mechanism.
Veterinary surgeon
Liz Mitchell
XLEquine practice
Scott Mitchell
Associates
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EQUINE MATTERS
Signs of EMS may include:
●
overweight
●
firm, and sensitive, fat on crest and
regional deposits
●
signs of laminitis (stilted gait, heat in feet,
increased digital pulses).
In EMS the fat that is laid down around the
body becomes hormonally active which
interferes with normal sugar and fat
metabolism. The result is an individual that
continues to put on weight and will,
eventually, show signs of laminitis. It is
not fully understood exactly how the EMS
leads to laminitis.
One of the features of the syndrome is
insulin resistance. In response to insulin
resistance, the body produces excessive
amounts of insulin to try to maintain normal
blood glucose concentrations. These high
levels of circulating insulin appear to be a
causative factor in EMS associated laminitis.
Diagnosis
Laboratory tests can be helpful in confirming
a diagnosis.
●
A raised resting blood glucose and/or
insulin level may be an indicator of EMS.
●
A more sensitive test is the glucose
tolerance test, which mimics the horse’s
response to eating a sugary feedstuff
(e.g. grass). The individual is starved for
six to eight hours overnight, then given
either a fibre-based feed (e.g. chaff)
containing a measured amount of
glucose or a measured amount of corn
syrup by dosing syringe. A blood sample
is taken two hours later and a raised
glucose/insulin level in this sample
gives a very strong indication of insulin
resistance and EMS.
Treatment/prevention
●
Feed a weighed amount of fibre based
diet to achieve a gradual weight loss.
●
Monitor weight using a weigh tape or
horse weigh scales.
●
Exercise is very beneficial as it improves
the body’s sensitivity to insulin.
●
Do not force exercise if laminitis signs are
present.
●
Metformin medication may aid in the
control of EMS. The exact mechanism of
action is unclear in the horse. In many
cases, metformin is only used when
exercise is not yet an option because
of laminitis.
●
Do not give sweet sugary feeds or tit-bits
as these will result in an insulin surge.
Our knowledge of laminitis prevention and
control has improved following the discovery
of EMS. This has led us to understand that it
is not the grass that causes the laminitis, but
more the individual’s hormonal/metabolic
response to eating the grass that causes the
problem.
Summary:
●
EMS can affect all ages of horse/
pony and mares/geldings/stallions;
●
affected individuals are usually
overweight;
●
affected individuals are more
susceptible to laminitis;
●
laboratory tests are needed for
accurate diagnosis;
●
EMS can be successfully managed.
Figure 1: EMS in natural living, native ponies is normal; it allows them to put on weight in
the summer and then use these fat reserves in the winter months.
Figure 2: Affected individuals are usually overweight
Figure 3: Regular weight checks using a weigh tape or weigh bridge is important in the
management of EMS
Figure 1
Figure 2
Figure 3
Liz Mitchell MA VetMB CertEP MRCVS,
Scott Mitchell Associates