Page 826 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Gastrointestinal system: 4.2 The lower gastrointestinal tr act 801

VetBooks.ir 4.126 major obstacle to survival of these cases and provid-
ing an adequate level of voluntary feed intake is key.
A highly palatable, high-energy and high-protein
feed of different components and consistencies to
suit individual needs is essential. Two-hourly small
feeds are initially useful. Regular hand walking and
short periods turned out to grass may be helpful.
Judicious use of NSAIDs is often beneficial, probably
by controlling low-grade abdominal pain and sys-
temic inflammation. Broad-spectrum anti-microbial
drugs are indicated in cases with aspiration pneumo-
nia. Long-term treatment (months) is required and
horses should be stabled during the treatment period.
Affected horses and herd mates should be removed
from the affected pasture, if possible. Reduction in
Fig. 4.126 Post-mortem findings of a horse with grazing time, particularly of young horses, and sup-
chronic grass sickness showing marked chronic impaction plementation of feeding have been used, but the effect
of the entire large colon and caecum with a very dried of these measures is unclear. Vaccination with C. botu-
out, clamped-down appearance of the gut wall, typical in linum type C toxoid may be a preventive option in the
these cases. (Photo courtesy Graham Munroe) future and this possibility is being evaluated.

Prognosis
Ileal biopsy with histological identification of neu- Mildly affected horses with the chronic form may
ronal loss and chromatolysis within myenteric and recover fully given adequate supportive care. A sig-
submucosa nerve plexuses provides a 100% definitive nificant expenditure of time and money is required
diagnosis. Post-mortem confirmation of the diagno- because of the severity of disease and gradual recov-
sis is more common, with demonstration of charac- ery. Horses that recover may return to normal func-
teristic neural degeneration of autonomic ganglia, tion, although peak performance may be affected
intestinal wall nerve plexi, brain and spinal cord. and residual problems with eating dry fibrous food
C. botulinum type C can be more commonly may persist. Approximately 50% of horses with
identified in the intestinal contents of horses with chronic disease survive with intensive nursing care.
EGS; however, it can also be found in some normal Well over 1 year may be required for return to full
horses and therefore intestinal culture is not useful competitive work. Mild, recurrent colic may persist
diagnostically. in some cases. Acute and subacute cases are invari-
ably fatal and prompt euthanasia is indicated.
Management
Treatment of the acute and subacute forms is not indi- INTESTINAL ADHESIONS
cated because affected horses invariably die. Some
horses with chronic EGS can recover. Selection of Definition/overview
appropriate cases to treat is difficult but ideally the Clinical problems associated with abdominal adhe-
horse should still be able to swallow to some degree, sions in horses include recurrent abdominal pain
have some remaining appetite and have an absence with or without intestinal obstruction.
of continuous moderate to severe abdominal pain. In
addition, the owners must be prepared for consider- Aetiology/pathophysiology
able commitment in time, nursing care and finances. Abdominal adhesions usually form following abdom-
Treatment of chronic cases predominantly requires inal surgery, particularly small-intestinal surgery or
intensive nursing care. Profound inappetence is the repeat coeliotomy. Peritonitis or prolonged ileus may