Page 1368 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

The foal 1343

VetBooks.ir required for more severely affected foals. The use of Clinical presentation
The foal is born covered in liquid brown meconium
artificial surfactants is commonplace in human medi-
cine but is usually cost prohibitive in equine practice.
and the amniotic fluid is stained yellow/brown.
Foals often have brown-stained fluid at the nostrils
Musculoskeletal support immediately after birth. The foals develop respira-
The degree of ossification of the cuboidal bones tory distress within the first few days of life and
is considered an indicator of maturity. Those with some may also exhibit signs of NMS. Foals often
poorly ossified carpal and tarsal bones (grade 3 or show an increased respiratory effort. The degree of
lower, using the scoring system developed by Poulos hypoxaemia and respiratory acidosis is dependent
and Adams) can develop severe crushing of the cuboi- on the quantity of fluid aspirated and the degree
dal bones and severe limb deformity. Restricted exer- of lung injury. Signs of respiratory disease are not
cise, maintaining steady growth and good farriery always apparent initially, and they may develop over
can help. In severe cases, limb splint bandages, casts time as pneumonitis worsens.
or custom-made limb supports have been suggested,
but evidence suggests that these individuals carry a Diagnosis
poor prognosis for future athletic performance. History and clinical signs can provide a presumptive
diagnosis. Visualisation of brown-stained fluid in the
Prognosis trachea with endoscopy, or a granular appearance of
The prognosis for survival after 300 days is influ- the caudoventral lungs on radiographs, provides fur-
enced by whether the pathology resulting in the pre- ther evidence. Confirmation is based on histological
mature delivery was acute or chronic. Those with examination of the lungs.
chronic placental pathology have a greater chance
for survival. Sepsis and metabolic dysfunction is a
common complication and often leads to rapid dete-
rioration and death 48–72 hours after birth. When 14.10
undertaking treatment of an immature foal it is
important to consider the future use of the horse,
because musculoskeletal problems may preclude an
athletic future. No individual parameter is the key
to the prognosis and a whole range should be consid-
ered before deciding on the best course of treatment.

MECONIUM ASPIRATION SYNDROME

Definition/overview
This condition is usually associated with maternal
or fetal stress. It is fairly uncommon. The severity of
the disease can vary from mild respiratory compro-
mise to fatal respiratory distress.

Aetiology/pathophysiology
The fetus can pass meconium during periods of
stress. If either the fetus gasps in utero or the fluids
are not cleared from the airways prior to the first
breath, meconium-contaminated amniotic fluid is
aspirated into the lungs (Fig. 14.10). This produces Fig. 14.10 A meconium-stained placenta from a
a chemical pneumonitis. mare whose foal suffered meconium inhalation.