iodine, to promote uterine contraction and stimulate detachment of the microvilli. If
the membranes have not been passed within 6-8 hours of foaling, more aggressive
therapy is required. In some cases (e.g. after dystocia), sub-clinical hypocalcaemia
appears to contribute to RP and an infusion of calcium gluconate and oxytocin can
lead to rapid resolution (Sevinga et al., 2002), or at least promote uterine
contractions that aid microvillus detachment; calcium infusion should be terminated if
cardiac dysrhythmia or profuse sweating develop. Although many texts advise
strongly against manual removal of the fetal membranes, it is worth examining how
firmly they are attached since in many cases the membranes are retained primarily
by the weight of contained fluid and can be easily and atraumatically removed; the
author would further argue that any ‘microretention’ resulting after relatively
uncomplicated removal is preferable and easier to manage than retention of the
entire membranes. The wisdom of forcible detachment of the membranes if they are
firmly attached over a large area is, however, more questionable since there is a risk
of inducing a uterine horn inversion, of the membranes tearing or of damage to the
endometrium. If a large area of the placenta is still firmly attached, it may therefore
be prudent to leave the membranes in place, encourage detachment by repeated
oxytocin and calcium administration and initiate supportive therapy; where the
membranes have been removed with difficulty, the mare should be treated as if the
membranes are still retained. If a placenta is manually extracted, or passed more
than 6 hours after foaling, it is advisable to perform a large volume lavage of the
uterus to remove debris and accumulating bacteria, to initiate 4-6 hourly oxytocin
treatment, and to arrange for the mare’s body temperature to be monitored at least
twice daily; temperature elevations beyond 38.5oC suggest the need for further
uterine lavage. Depending on the severity of the problem and the circumstances
(e.g. in a clinic, on farm), further supportive treatment in the form of broad spectrum
antibiotic therapy, anti-inflammatory agents (e.g. flunixin meglumine) or other antiendotoxic agents (e.g. polymixin B), and further laminitis prevention measures
should be considered.
While RP is the primary cause of acute septic metritis and any form of obstetrical
intervention will predispose to the latter complication, septic post-partum metritis can
also arise after uncomplicated foalings, or because a small piece of membrane was
retained unnoticed. This is why the author is a firm advocate of a routine examination
of the uterus (initially by per rectum palpation and ultrasonography) at 12-24h postfoaling, even if there are no indications that there is anything wrong with the mare.
The first clinical indication of acute septic metritis is usually pyrexia, and because the
condition can rapidly deteriorate into the metritis-toxaemia-laminitis syndrome,
particularly in draft breeds, twice daily asses