the cervix (colour, tone, secretions) gives useful information with regards to
the mare’s stage of cycle and problems such as a purulent uterine discharge,
urine pooling in the vagina or damage to the cervix (or other parts of the
vagina) caused during a previous dystocia. In mares with a history of recurrent
bloody vulval discharge, particularly during oestrous or mid-gestation, it is also
important to inspect the vagina around the hymenal remnants (especially
cranial aspect of vagino-vesical junction) for evidence of bleeding varicose
veins. If the mare is in oestrus, a guarded uterine swab or brush may be
advanced through the speculum and thence the cervix (or passed blindly
using a sterile-gloved hand) to obtain uterine fluids for cytological and
microbiological examination. Alternatively, a uterine fluid sample can be
obtained by ‘low volume’ uterine lavage via a balloon catheter or flexible
endoscope.
A manual examination of the vagina and cervix can also be extremely useful
and informative, for example for detecting the long, tortuous cervix common in
elderly maiden mares, or cervical tears in mares with a history of a difficult
foaling or repeated uterine infections and short cycles, or cervical adhesions
in the case of mares presented with gross uterine fluid accumulation
(pyometra).
Cytological and microbiological examinations
A uterine mucus or endometrium sample should be placed in an appropriate
medium and taken to a laboratory for culture. If there is any delay in getting
the sample to a laboratory it should be maintained at 5oC to prevent
overgrowth of insignificant or contaminating bacteria. A further sample of
uterine fluids should be used to prepare a smear for cytological examination.
By combining these two examinations there is much less chance of drawing
an incorrect conclusion. The smear should be stained with a Diff-Quick like
stain and examined under high power (x40 objective = x400 magnification).
The presence of sheets or clumps of endometrial epithelial cells will confirm
that the smear is representative of the uterine lumen, while the presence of
large numbers of neutroph ils (particularly if they are degenerate or contain
bacteria) confirms the existence of an acute endometritis. Bacteria, fungi or
yeasts may also be visible in the smear where the latter are important
because they are often found in the absence of an obvious acute
inflammatory response (i.e. no neutrophils).
Microbiological examination should involve culture for both aerobes and
anaerobes, and in problem mares (particularly if there is a history of repeated
antibiotic treatment) it is sensible to culture for yeasts/fungi. In the case of
bacteria, antibiotic sensitivity should also be determined so that the uterus can
be infused with appropriate antibiotics if the severity of the clinical signs or the
identity of the bacteria (e.g.Pseudomonas aeruginosa) warrants treatment
above and beyond simple uterine lavage with saline. Meticulous preparation,
a careful swabbing technique and good storage prior to culture are important if
the diagnosis is not to be confused by contaminating bacteria leading to false
positives or masking significant pathogens. The growth of bacteria of mixed
types or in small numbers should be regarded with suspicion unless the
cytology also indicates an endometritis.
15-‐18
February
2016
East
London
Convention
Centre,
East
London,
South
Africa
90