Page 475 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

450 CHAPTER 2

VetBooks.ir Differential diagnosis increase end-of-year pregnancy rates. Oviductal pros-
taglandin E treatment has been used in mares that
Twinning; embryonic defects; endogenous prosta-
2
glandin release following stress; concurrent systemic
disease; poor nutrition; oviduct obstruction; reduced are repeatedly negative at first pregnancy scan but
have no other discernible uterine/ovarian abnormal-
oocyte viability with ageing mare. ity. The technique ‘flushes’ the oviducts of debris
making the transportation of the conceptus from the
Diagnosis uterine tubule to the uterus easier. The understand-
Serial ultrasound examinations demonstrate loss of ing of EED, conception failures and treatments is
the conceptus or growth abnormalities in the devel- likely to advance as further research is performed.
opment of the conceptus/embryo. Pregnancy diag-
nosis is possible from 10–12 days and the conceptus Prognosis
will develop at a predictable rate and appearance, The prognosis is good to guarded depending on the
which can be monitored by transrectal ultrasonog- cause.
raphy. Failure to maintain a normal growth rate sug-
gests a compromised pregnancy. GASTROINTESTINAL COMPLICATIONS OF
LATE PREGNANCY AND PARTURITION
Management
In mares suspected of EED or a failing early preg- Definition/overview
nancy, it is advisable to induce luteolysis with pros- This rare group of conditions is mainly seen in the
taglandin and return the mare to oestrus where any post-partum mare and includes rupture of the cae-
uterine problems can be corrected and the mare cum or right ventral colon, and contusion of the
re-bred. In mares prone to EED, exogenous proges- small intestine/small colon/rectum and attaching
terone supplementation is recommended until the mesentery, with possible secondary rupture. Colonic
endometrial cups are present. Buserelin has also been torsion is particularly common in post-partum
used at day 10 post ovulation to support the function mares in the first 4 weeks (Fig. 2.58).
of the CL and has been reported to improve preg-
nancy rates in some cases. In the majority of cases, Aetiology/pathophysiology
early detection of EED by regular examination is the The caecum and large colon may be traumatised dur-
best way to minimise delays in re-mating and thereby ing parturition, particularly if they are filled with ingesta
and/or gas. Fetal limbs may directly damage loops of
bowel, or prolonged or abnormal straining may damage
2.58 or rupture bowel trapped in the pelvic canal between
the fetus and bony walls. Spontaneous rupture can
occur in the caecum with marked increase of abdominal
pressure (Fig. 2.59). Ruptures commonly occur within
15 cm of the ileocecal valve, ventrally in the caecum and
caudally in the right ventral colon. Contusions of the
small intestine, small colon or even rectum, plus their
mesentery, can also occur at parturition. Severe dam-
age can lead to rupture of the bowel or damage to the
mesentery, with incarceration or vascular occlusion and
segmental ischaemic necrosis. External prolapse of the
small intestine/small colon can occur through the rup-
ture, leading to gross contamination.
Fig. 2.58 Surgical intervention in a broodmare
7 days post foaling that revealed a 360° large colon Clinical presentation
torsion. Note the enlarged and discoloured left dorsal The presenting signs will relate to the degree of dam-
and ventral colon, with a haemorrhagic mesentery. age to the bowel and when this occurred (Fig. 2.60).