For the Health of It
Prepubic Tendon Rupture Reprinted with permission from Volume 31 , Issue Number 1 of Equine Disease Quarterly
The prepubic tendon extends from the brim of the pelvis and joins with the abdominal muscles to support the abdomen and abdominal viscera . Mares can rupture ( tear ) the prepubic tendon , either partially or fully , and the associated muscles of the abdominal wall . Prepubic tendon rupture is an uncommon but serious condition in late pregnancy that may have a poor prognosis and can result in death of the mare and fetus .
The exact cause of prepubic tendon rupture is not known , however , the condition is more common in older mares that have had multiple pregnancies , draft breeds , mares carrying twins , and mares with placental abnormalities such as hydrops ( hydroallantois or hydroamnion ).
Mares with prepubic tendon ruptures exhibit signs of colic-like pain , elevated heart and respi- ratory rates , and reluctance to move or lie down . Changes in the shape of the ventral abdomen ( underbelly ) may be first noted , followed by a rapidly progressive swelling ( edema ) that can extend from the udder towards the chest . The udder may be swollen and teats may point toward the mare ’ s head instead of downwards , and blood may drip from the teats . Touching the ventral abdomen is often resented . Some mares will adopt a ‘ sawhorse ’ stance with a tilted pelvis and elevation of the tailhead . Other mares may die after a short illness . Diagnosis of prepubic tendon rupture is difficult to confirm and is usually based on characteristic clinical signs .
The choice of therapy for mares with prepubic tendon rupture varies . It will depend on the extent of the
14 • Walking On rupture , ability to control the mare ’ s pain , and stage of gestation . The relative value of the mare and foal may also be considered . Complete rupture of the prepubic tendon has a poor prognosis for the mare because the tendon cannot be surgically repaired .
Conservative therapy will usually involve restricting the mare to stall rest , carefully applying ‘ belly bandages ’ to support the ventral abdomen , and alleviation of pain using a variety of drugs . Progestins may be given to keep the uterus in a quiet ( not contracting ) state . Close monitoring of the fetus to detect fetal stress is required with frequent ultrasound examinations via the mare ’ s abdomen to monitor fetal heart rate and activity .
Stage of gestation is an important factor when therapy options are being considered . If the mare is close to term ( 330 days of gestation or later ), induction of labor or a caesarean section may be considered . If the mare is induced , then foaling must be assisted as she has limited or no ability to contract abdominal muscles during active labor . If the foal is successfully delivered , it is considered at high risk of developing problems such as neonatal sepsis . Colostrum supplementation may be needed , and the foal may not be able to suckle the mare due to severe udder swelling .
For mares that rupture the prepubic tendon before 330 days of gestation and in which pain can be managed , a decision may be made to support the mare so the fetus can reach 330 days of gestation or longer . The last part of pregnancy is very important in determining viability of the foal , as most of the fetal maturation that ensures the foal is ready for life outside the uterus happens in the last 10 days of gestation . For mares in which pain cannot be well managed , euthanasia should be considered .
Mares with prepubic tendon rupture that survive foaling or caesarean section should not be bred again . Some mares that survive foaling may subsequently need to be euthanized due to intractable pain .
CONTACT : Erica Gee , BVSc , PhD , DipACT e . k . gee @ massey . ac . nz + 6463505328
School of Veterinary Science Massey University Palmerston North , New Zealand