Page 468 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Reproductive system: 2.1 The female reproductive tr act 443

VetBooks.ir parturition, surgical repair post parturition, retire- 2.50
ment from breeding (except by embryo transfer) and
euthanasia. The prognosis is guarded to poor.

Aetiology/pathophysiology
Progressive rupturing of the prepubic tendon and/or
the rectus/transverses abdominus muscles can occur
either singly or in combination in late-pregnant
mares. The exact aetiology is unclear, but appears
to be related to increasing strain on these struc-
tures from the weight of the developing pregnancy,
leading to weakening and eventual rupture of the
supporting tissues. Previous damage, poor fitness,
twin and hydrops pregnancies, multiparity, increas-
ing age and draught breeds may all be predisposing
factors.
Fig. 2.50 Use of an abdominal support bandage in
Clinical presentation a mare after foaling that had early signs of ventral
The condition usually occurs in the last trimester of rupture of the abdominal wall prior to parturition.
pregnancy and will often present initially as a ven-
tral abdominal oedematous plaque of up to 15 cm
thickness. There may be significant abdominal pain, laxatives given to reduce abdominal straining.
difficulty in moving and, slightly later, dropping of In severe or progressive cases, induction of parturi-
the abdomen or even asymmetrical bulging. If the tion is often considered, but fetal readiness for birth
prepubic tendon completely ruptures, the mammary should be checked before this is undertaken. The use
gland appears to move cranially and secretions may of dexamethasone to induce fetal maturation prior
be blood tinged, the pelvis tilts with the tuber ischii/ to induction should be considered. If the mare does
tail head becoming more elevated, and the mare will reach parturition, this should be closely monitored.
assume a lordosis (‘rocking horse’) stance Additional assistance is invariably required due to
loss of abdominal pressure. Caesarean section may
Differential diagnosis be used in some cases. Surgical repair of prepubic
Other abdominal hernias or ruptures including post tendon ruptures is not possible and in other types
surgery and traumatic; mammary gland/ventral of rupture is rarely undertaken due to economic
abdominal wall oedema (physiological or pathological). considerations and poor success rates, particularly
in severe cases. It is usually carried out after foal-
Diagnosis ing, when all the oedema and reaction have subsided,
History and clinical presentation are very helpful, using a mesh implant. Euthanasia may be the only
but confirmation of the damage is best achieved humane course in severe cases. It is not recom-
using transabdominal ultrasonography. Rectal mended that these mares are bred again. Alternative
examination may identify the prepubic damage in options include ET and oocyte harvest. Foals born
the midline cranial to the pubis. to these mares are always high risk, particularly due
to problems with colostral quality, and they should
Management be treated appropriately.
The mare should be restricted to a large stable.
Abdominal supports have been used in these cases Prognosis
in late pregnancy, but they can be difficult to man- The prognosis is guarded to poor depending on the
age in the long term (Fig. 2.50). Analgesics should degree and extent of the damage and the stage of preg-
be given to control pain and inflammation, and nancy. Mares should be retired from natural breeding.