AQHA Magazine September / October 2019 AQHA Sept-Oct 2019 WEB | Page 26

PG.24
HORSE HEALTH
processed cereal grains is potentially more hazardous
than the feeding of raw cereal grains.
The health benefits of low sugar/starch feeds also extend
to the risk of peri-foaling colics and the immunity levels
(IgG) of the colostrum. The periparturient mare has
increased risk of a number of types of gastrointestinal
colic : large colon displacements and torsions, caecal
perforations, mesoduodenal tears and damage to the
small colon. In colic research studies it was reported
that half of the admissions to University of California at
Davis for surgical correction of colonic volvulus (LCV)
were mares that had foaled in the previous 60 days.
And in Kentucky, 91% of the colonic displacements and
volvulus cases requiring surgery occurred in broodmares.
Risks for the development of LCV included: broodmare,
age and foaling within the past 90 days. Management
risk factors for LCV include: stabling in the previous 14
days, increased feeding of starch/sugar concentrates,
decreased dry matter intake and a change in pasture or
hay batch in the past 28 days. These factors affect the gut
flora or biome (the number of healthy versus the number
of unhealthy bacteria). Changes in the biome were found
to be present 10-17 days before the onset of colic.
Changes in the biome and in exercise affect gut function –
with stabling having a major impact on gut function. With
stabling comes a change in not just the frequency, but in
the synchronous order of gut contractions – multiplying
the risk for torsions, twists and displacements. All are
associated with increased time spent in a stable and
a recent change in starch/sugar concentrate feeding.
Stabled horses also have increased risk of large intestinal
impactions, a change in amount of exercise is a risk factor
for simple colonic obstruction and distension, and pelvic
flexure impactions are associated with transferring a
horse from pastured to stabled management.
thyroid function. Magnesium reduces insulin-resistance
and as soils in many areas are becoming increasingly poor
in magnesium as a result of acidification, a magnesium
supplement is often necessary.
Protein, energy and mineral deficiencies also adversely
affect the hooves. The incidence of foot abscesses,
white line disease, wall cracks and seedy toe is higher
in winter when wet muddy conditions reduce the ability
to exercise and create unhygienic conditions. To prevent
weaknesses and subsequent pain, lameness and expense,
it is essential to provide correct zinc, calcium, biotin and
protein and to avoid excesses of selenium and vitamin A
- both of which have been linked to hoof cracks and poor
quality wall. As mares gain weight during pregnancy the
load through the hoof wall further weakens the internal
structures and increases the incidence of sub-clinical
laminitis and foot problems. If the ground is hard and dry,
make a damp/puddle (perhaps near a water trough) so the
hooves can maintain their hydration. The propensity to
develop skeletal and bone conditions develops during late
pregnancy when the bones begin their most rapid period
of growth (Figure 1).
Feeding a fat/fibre diet that contains omega 3 oils versus
sugar/starch feeds has been shown to increase milk
omega 3 oils. Omega 3 oils have a role in the prevention
of gastric ulcers through the enhancement of stomach
mucosal protective factors. The results of several studies
have found that the higher omega 3 content in the milk
of fat/fibre diets in mares may reduce the risk of gastric
ulcers in foals. The time course for hock and stifle OC is different. Most
hock lesions are generally present at 1 month of age and
there is evidence they can develop during gestation, so
preventative management should be practised before and
after birth Stifle lesions appear between 3 and 5 months
of age. The significance of this is that correct, sound bone
growth must be the priority for the weanling. There is a link
between above average weight gains and onset of bone
diseases. Muscle growth should not be pushed forward
while the bones and joints are vulnerable. A lighter, leaner
weanling with appropriate height (remember height is an
indication of bone growth, not muscle) is the ideal.
Energy intake of mares in late gestation also affects the
load on the mares legs and hooves, the occurrence of
flexural and angular limb deformities, and colostrum
quality. Colostrum from mares on a lower energy intake
and fat/fibre concentrate had a greater specific gravity
and increased IgG concentrations (16.3g IgG/L vs
12.4g/L). Foals from fat and obese mares show decreased
24 hour IgG concentrations compared to mares in ideal
body condition on lower dietary energy. And immunity
is also influenced by vitamin E intake – supplementing
2500iu of vitamin E from 3 weeks pre to 2 days post-
foaling enhances passive immunity and stimulates serum
antibody synthesis, particularly IgG. And keep mineral
intakes in mind too when preparing diets for pregnant
mares. Correcting mineral deficiencies and imbalances
impacts significantly on laminitis, insulin resistance and The time course for hock and stifle OCD is different. Most
hock lesions are generally present at 1 month of age and
there is evidence they can develop during gestation, so
preventative management should be practised before and
after birth Stifle lesions appear between 3 and 10 months
of age. The significance of this is that correct, sound bone
growth must be the priority for the weanling. There is a link
between above average weight gains and onset of bone
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