Page 523 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

498 CHAPTER 2

VetBooks.ir fluid for diagnosis, and they may take endometrial persistent luminal fluid, sexual rest for two to three
oestrous cycles is warranted.
swabs to confirm the presence of neutrophils and
bacteria.
Prognosis
Management Generally, the prognosis deteriorates with age and
Early recognition is essential, by ideally identify- continuing degeneration of the reproductive tract.
ing the ‘high-risk’ mares by age, previous breeding It becomes increasingly difficult to establish a preg-
history, reproductive tract examination and semen nancy in these mares despite extensive treatment.
type (chilled and frozen semen increases incidence
of PMIE) prior to breeding and targeting treat- CHRONIC UTERINE INFECTION
ment. Pre-breeding oxytocin and uterine lavage can
be helpful to prepare the uterus for breeding. Post- Definition/overview
breeding treatment includes the use of an ecbolic CUI can occur in PMIE mares that are repeatedly
drug, intrauterine antibiotics and uterine lavage, bred in one breeding season, particularly if they are
alone or in combination, depending on the perceived not treated appropriately. Mares can become sus-
severity of the PMIE. A Caslick’s procedure may be ceptible to endometritis where there is a breakdown
appropriate in some cases. in their normal uterine defence mechanisms that
Uterine lavage with 1–3 litres of warmed saline allows normal microbiological flora to populate the
or lactated Ringer’s solution between 4 and 8 hours uterus and cause a persistent uterine inflammation.
post breeding, plus oxytocin (10–20 IU i/v or i/m), Repeated and untreated severe endometritis will lead
should hasten the removal of post-coital debris, con- to severe and chronic inflammatory changes in the
tamination and fluid without affecting the semen uterus, leading to fibrosis and degeneration.
and before the mare mounts a major inflammatory The most commonly isolated causative organ-
response. Broad-spectrum antibiotics are often isms of endometritis are β-haemolytic streptococci
infused into the uterus following lavage, but their (S. zooepidemicus), Staphylococcus aureus, Escherichia coli,
use post breeding is reserved for mares with PMIE Pseudomonas spp., Klebsiella spp., yeasts and fungi (e.g.
and bacterial endometritis. Appropriate use and Candida spp., Aspergillus spp., Mucor spp., Allescheria
choice of antibiotics is essential. The procedure can boydii) and Bacteroides fragilis (anaerobic).
be repeated 24 hours after breeding if there is still The infection can be introduced by: pneumo-
evidence of fluid accumulation in the uterus. Mares vagina and/or incompetent cervix; parturition;
with particularly severe oedema in the uterine wall copulation, especially if repeated; and veterinary
and lymphatic lacunae can have additional treatment gynaecological procedures.
with 250 µg cloprostenol, which induces further Some specific bacterial infections, and fungal and
uterine contractions. However, cloprostenol should yeast infections, may be induced by the repeated use
not be used after ovulation as it is now recognised of intrauterine antibiotic and/or antiseptic therapy.
that it may induce luteolysis as quickly as the day
after ovulation. Clinical presentation
Recently, the use of a single dose of dexametha- Mares with chronic infectious endometritis have
sone at the time of breeding or oral prednisone reproductive histories including repeated breeding,
(starting 24 hours prior to breeding and continuing poor fertility, PMIE, conformational abnormali-
to ovulation) has been advocated as a means of down- ties of the vulva and repeated intrauterine therapies.
regulating the immune response in mares known to They usually present with a vulval discharge of vary-
be prone to PMIE. As with any corticosteroid, there ing nature and amount.
is an associated risk of laminitis. Specific infections
and physical defects (e.g. perineal defects) need to be Diagnosis
identified and treated. If the endometritis becomes A reproductive examination usually produces a posi-
chronic and established, particularly if there is active tive endometrial culture result and neutrophils should
ongoing inflammation, severe oedema/lacunae or be seen on uterine cytology. On ultrasonography