May
25
Written by:
Surgi-Care Center for Horses
5/25/2011 2:50 PM
Foal season is upon us – the hope of
any horse owner with a mare ready to foal is to have a healthy, strong foal.
There are a number of illnesses and complications that can affect a newborn
foal, such as; failure of passive transfer, septicemia, neonatal isoerythrolysis, musculoskeletal
disorders, and the condition referred to as peripartum asphyxia syndrome.
Peripartum asphyxia syndrome (PAS) is
also known as neonatal maladjustment syndrome (NMS). The layperson terminology
for this condition is ‘dummy foal’. Foals affected display symptoms that
include barking like dogs, seizures, aimless wandering, the lack of suckle
reflex, as well as a loss of affinity for the dam. The clinical signs observed
in the ‘dummy foals’ are due to any event that impairs normal blood flow between
the mare and foal prior to and during the birthing process. Asphyxia, which is the
lack of oxygen delivery, can result from the interruption of umbilical blood
flow, premature separation of the placenta (red bag), direct trauma to the
chest during the birthing process, surges in blood pressure to the foal’s brain
due to the mare’s contractions, and problems with both the fetus and mare, such
as infection.
There does not seem to be any
specific incident that leads to the development of PAS in foals. It has been associated
with rapid seemingly uncomplicated deliveries, dystocias, induced deliveries,
cesarean sections, placentitis, premature placental separation, twinning,
severe maternal illness, and overdue or prolonged pregnancies. Affected foals
may behave and function normally for up to 24 hours and then become lethargic
and non-responsive. The majority of the clinical signs observed in affected foals
are neurologic disorders such as the aimless wandering and non-responsive behavior.
There are multi-systemic effects of the asphyxia, which affect the gastrointestinal
tract, the kidneys, the heart and lungs, as well as other systems.
Diagnosing PAS is based on clinical
signs, laboratory findings/bloodwork, and ruling out other causes of neurologic
disorders such as infections and birth defects. Treatment of foals with PAS is very
intensive and critical. Therapy is complex because dysfunctions of the
previously mentioned organ systems must be addressed as well as general
supportive care for the critical patient. Treatment is focused on controlling seizures,
providing adequate nutrition, correcting blood abnormalities, and providing respiratory
support (oxygen therapy) if needed.
It is important that the foal is kept
warm, hydrated, properly ventilated (oxygen) and that adequate immune transfer
(colostrum and/or plasma) and nutritional requirements are provided. The
equipment needed to monitor and support these foals as well as the 24 hour
nursing care require a critical care unit to properly treat PAS. Given proper supportive care, it is shown
that approximately 70% of asphyxiated foals recover.
In closing, PAS is a syndrome that
requires early recognition of clinical signs to accelerate proper supportive
care measures necessary for the foal’s survival.
Contact
Surgi-Care Center for Horses at 813-643-7177 or email lkuebelbeck@surgi-carecenter.com with
any questions regarding this topic.