Page 511 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

486 CHAPTER 2

VetBooks.ir Clinical presentation or it may result from haematogenous spread of an
infection from another body system. The resulting
The contralateral ovary, behavioural cycle and endo-
crine patterns are normal. An HAF/PAF starts from
a follicle that grows normally but fails to empty and inflammation may reduce the patency of the oviduct
and lead to delayed sperm or ovum passage, thereby
ovulate in the usual way. Matings on these follicles affecting fertility. In extreme cases the lumen of the
are rarely successful. oviduct or the uterotubal sphincter can be completely
occluded. Adhesions between the infundibulum and
Differential diagnosis an ovary or the uterus are a common post-mortem
GCT; other ovarian neoplasia; anovulatory follicle; finding, but their significance in relation to fertility
ovarian abscess; transitional ovary. is unknown. Very rarely, tumours of the oviduct may
occlude the lumen, and ovarian cysts or tumours
Diagnosis may block the entrance to the oviduct or physically
Ultrasonography of the ovary with an HAF may impinge on it. Parafimbrial cysts and fimbrial adhe-
reveal a mass similar to a GCT, but HAFs are usually sions may affect the ability of the fimbria to receive
more uniformly echogenic, have an ovulation fossa the oocyte and pass it to the oviduct. Occlusions can
present and a characteristic homogeneous appear- also occur with collagen-type material, at present of
ance to their contents. Their appearance normally unknown origin, particularly in older mares.
changes more rapidly (i.e. within days) compared
with that of a GCT. The ultrasonographic appear- Clinical presentation
ance of a PAF is the same as for a large follicle with Oviduct disease can cause reduced fertility and endo-
hypoechoic fluid. There is a chance that the HAF metritis. Older mares are more likely to be affected
will luteinise and go on to produce progesterone, in (mean age 18 years old).
which case the serum progesterone level will rise.
Diagnosis
Management A full reproductive tract and fertility examination
Treatment is not necessary as the ovarian structure should be carried out and other more common causes
will be absorbed. Prostaglandin can be used to cause of mare infertility explored before oviduct problems
luteolysis and a return to oestrus; however, it should are considered. Patency of the oviducts can be tested
be appreciated that prostaglandin use can increase using a fluorescent microsphere or starch-grain test,
the risk of an HAF occurring. HAFs and PAFs are via laparoscopy or ultrasound-guided transvaginal
more common in the spring and autumn transition deposition, both of which are difficult and awkward
periods. to carry out. The normal transit time from ovary
to cervix is between 4 and 7 days. Hysteroscopy of
Prognosis the uterus and evaluation of the uterotubal junction
The prognosis is good as there is no long-term effect may reveal cysts, adhesions, fibrosis or other uterine
on the mare unless the structure becomes extremely abnormalities, which may cause obstruction. The
large (Fig. 2.95). oviducts can be palpated per rectum, visualised on
ultrasound examination, viewed directly via laparos-
OVIDUCT DISEASE copy or examined directly at exploratory laparotomy.

Definition/overview Management
Lesions of the oviducts (Fallopian tubes) are rare Endometritis should be treated appropriately
in the mare, often only being recognised at post- (p. 498) after swabbing for bacterial culture and
mortem examination. sensitivity testing. Haematogenous infections are
treated using systemic antibiotics. Adhesions can
Aetiology/pathophysiology be broken down surgically and prostaglandin E
2
Direct spread of a uterine infection (endometritis) has been applied to the oviducts via laparoscopy to
or spread from a body cavity may lead to salpingitis, encourage contractions of the oviduct to ‘clear’ the