Finances and the practical implications also need to be considered when
selecting your drug therapy.
Do not wait for culture results prior to initiating antimicrobials. Consider which
bugs are likely to be involved and make an educated guess at which
pharmacological agents to start with. A good first choice is a combination of
an aminoglycoside- preferably amikacin in the foal 25-30mg/kg i.v. once dailycombined with penicillin. Intramuscular penicillin (20-50000iu/kg i.m. twice
daily) injections can become painful for the neonate, so i.v. crystalline
penicillin may be preferred (20-50000iu/kg i.v. four times daily).
Aminoglycosides do have the potential to cause nephrotoxicity through
accumulative dosing so renal parameters plus/ minus drug assays should be
measured.
Alternatively, third and fourth generation cephalosporins may be considered,
(Ceftiofur 5-10mg/kg i.m. or i.v. infusion twice- four times daily, Ceftriaxone
25mg/kg slow infusion i.v. once or twice daily). Ceftiofur must not be given as
a rapid i.v. injection due to rapid renal clearance and failure of the drug to then
reach and maintain MIC’s. The higher doses will provide broader gram
negative cover.
Until biochemistry results are obtained it may be worth avoiding drugs that
undergo significant hepatic metabolism, i.e. chloramphenicol. If anaerobic
cover is required then the use of metronidazole can be considered (1525mg/kg two/three times daily in foals PO or per rectum). Once culture
results are obtained then antimicrobials can be changed accordingly, bearing
in the mind the pharmacological differences between in vitro and in vivo
activities.
• Nutritional support
Nutritional support is vital. Malnutrition has been proven to compromise
recovery. Sick foals will have increased metabolic rates, disturbed utilization
of nutrients, decreased suck reflexes and appetite. Ileus is a common
complication of HIE and SIRS. Enteral feeding is preferable but poorly
tolerated in many sick foals with compromise to the gastrointestinal tract. You
have to decide when to provide nutritional support, how to provide it, what to
use and how much to give.
If enteral feeding is to be employed then the gut must be ready for this. The
meconium must have been passed or be in the process of passing through,
there must be no gastric reflux present and no abdominal distension present.
Gut sounds must be present on auscultation. Ultrasonography must not
reveal any small intestinal distension and the foal MUST NOT BE
HYPOTHERMIC. Ideally fresh mares milk is the best option for the neonates
because of its unique nutrient composition, increased bioavailability of
nutrients, immunologic properties, promotion of maternal-neonate bonding,
and present of hormones, enzymes, and growth factors.
If the foal is not on suck, the dam should be stripped every two hours (the use
of oxytocin may aid in milk let down), this milk filtered, labelled and
refrigerated. If the dam is not providing enough fresh milk, this can be
combined with frozen mare’s milk or milk replacer or goat’s milk. Keep the
consistency constant, do not chop and change from one product to another.
15-‐18
February
2016
East
London
Convention
Centre,
East
London,
South
Africa
*