Page 480 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Reproductive system: 2.1 The female reproductive tr act 455

VetBooks.ir Clinical presentation fungal hyphae are abundant on smears and histopa-
thology of the placenta, and inflammatory foci are
Vaginal discharge and premature lactation may pre-
cede bacterial or fungal abortion and these mares
should be considered high risk and have detailed present in the fetal liver. The organism can be cul-
tured in some cases from the uterus. Aspergillus spp.
fetoplacental assessments carried out. The appear- are the most frequently encountered fungi involved.
ance of the placenta following a bacterial abortion
can vary from minimal changes in acute cases to a NON-INFECTIOUS CAUSES
thickened, oedematous placenta, either generally OF ABORTION
or in localised areas. The chorionic surface is often
brown and covered in exudate. TWINNING
Twinning was once the single most common cause of
Diagnosis abortion (see p. 444). It now accounts for only 6% of
Bacterial organisms may be cultured or seen on stained abortions following the widespread use of ultrasonog-
cytology smears from samples taken from the aborted raphy of the reproductive tract in early pregnancy and
fetus/placenta and mare’s uterus. Leptospiral abortion is early recognition and management of the condition.
difficult to diagnose as bacterial isolation is often diffi-
cult and post-mortem findings in the fetus are variable. UMBILICAL CORD PROBLEMS
Immunofluorescence and special staining techniques Torsion of the cord, or strangulation of the fetus by
may allow demonstration of the organism in tissues, and the cord, can lead to fetal asphyxia, fetal death and
rising antibody titres in the mare are supportive. fetal necrosis. There is an increased risk of cord tor-
sion in pregnancies with an increased umbilical cord
Management length. Data is published for various breeds
Treatment of advanced bacterial placentitis is very
difficult and abortion is a common outcome once BODY PREGNANCY
the infection becomes established. Prevention of Unknown cause.
ascending infections and endometritis by corrective
surgery is essential and is covered in detail elsewhere VILLOUS ATROPHY
(p. 496). A vaccine is available for Salmonella abortus Endometrial scarring or lymphatic cysts can give
equi abortion in some parts of the world and other rise to a reduced ability of the placenta to associate
non-equine vaccines have been used in leptospiral closely to the endometrial surface, thereby reduc-
abortion. Careful management and hygiene practices ing nutrition to the foal. These conditions are most
are important to avoid exposure to bacterial organ- commonly seen in the older mare with a history of
isms before and after abortions. The monitoring of endometritis. Uterine biopsies can be taken to iden-
mares prone to ascending bacterial infections is rec- tify mares with endometrial disease or degeneration.
ommended. CTUP measurements every month from
3–5 months of gestation can help identify the early FETAL ANOMALIES
development of placentitis and its prompt treatment. Genetic or developmental abnormalities of the
The prognosis is better for cases identified early. fetus, which are incompatible with life, will gener-
ally result in early pregnancy failure but can lead to
FUNGAL ABORTION abortion after 6 months of gestation.
This is a rare cause of late abortion (generally >10
months) or stillbirth and is usually an ascending infec- MATERNAL DISEASE
tion through a damaged cervix. The gross appearance Maternal disease includes any condition, disease or
of the placenta and fetus is similar to a bacterial abor- environmental circumstance that causes stress in the
tion, but there may be a mucoid exudate and yellow pregnant mare (e.g. maternal injury, pyrexia, endo-
leathery areas of the placenta. There may or may not toxaemia, malnutrition, toxic plants, medications
be a vaginal discharge. In some cases the foal may be and transport), uterine abnormality and premature
born alive but congenitally infected. Microscopically, placental separation.