The postpartum mare: Managing basic problems (Proceedings)

Aug 01, 2010

The perinatal period in the mare is associated with many medical and surgical conditions that can be life threatening. These include retained placenta; metritis, laminitis, septicemia complex; colic, and rupture of a viscus, artery or uterus. Most are emergencies and if left unattended can have dire consequences. The minimal diagnostics to be performed at presentation of a sick postpartum mare should include a thorough history, a basic physical examination, rectal and uterine examination, and measurement of total protein and PCV. Ultrasonographic evaluation of the abdomen, an abdominocentesis and passing a stomach tube per os may also be indicated. Veterinarians must determine if severe pain is due to a ruptured uterine artery or is associated with a gastro-intestinal problem. In some cases, the diagnosis is made on the surgery table. The outline presented below is a guideline for differentiating and treating each condition. These notes are to be a aid in the discussion of the clinical cases.

A. Retained placenta

1. Due to the serious sequelae that are possible, retained placenta should be handled as an emergency.
Tissue breakdown and bacterial growth may lead to metritis- laminitis-toxemia
Placenta should be out in 4 hrs; retained most commonly in the non-pregnant horn
Associated with conditions that cause tissue inflammation-dystocia, placentitis, abortion and cesarean section.
Common in Friesian mares!!! Afflicted mares have low serum calcium concentrations.
Treatment should be initiated by 6 hrs postpartum; some mares may not experience problems but cause of the dire consequences that may occur it is prudent to treat all mares.

2. Principles of treatment
Evacuate uterus - atraumatic expulsion of membranes
Control bacterial growth
Prevent laminitis

3. Treatment before 6 hrs
     Methods of delivery and doses
     Small bolus IV (10-20 IU)
     Add to intravenous fluids 40-60 IU/5 L
     Frequency of administration-controversial Recommend 10-20 IU every 4 hr (based on unpublished data from UF)

Antibiotics + nonsteroidal anti-inflammatory drugs if placenta has not passed by 8 to 12 hrs (length of time depends on circumstances and cleanliness); Monitor mare 1 to 2 times daily until placenta has passed.

Client education Let owner know that mare may become extremely ill; owner should evaluated every 6 hrs for depression, lameness, anorexia

Re-distension of chorio-allantois

Manual removal; placenta may tear, leaving small tags that may serve as a source for bacterial adherence; Twirl placenta and lift out of uterus, don't pull downward

4. Following removal carefully examine placenta
Know normal appearance
b. Make sure it is all present - if not perform careful aseptic evaluation of uterine lumen; Mares usually retain placenta in tips of horns

5. Treatment after 12 hrs

Systemic antibiotics + oxytocin + NSAIDS (duration depends on mare's clinical condition). Minimum antibiotic therapy 5 days. Culture uterus if mare becomes ill or if mare is ill and does not improve within 72 hrs while on antibiotics; If mare is depressed, febrile, or anoretic may need to place mare on intravenous fluids. Five L of fluids may be spiked with 40-60 IU of oxytocin and 120-150 ml of calcium gluconate (23%). Deliver slowly - 1 to 2 L/hr; If in the field administer 150 ml of calcium gluconate (23%) L of saline; follow by administration of 1 ml of oxytocin

Manual re-evaluation daily

If only small tags of placenta remain, the uterus should be lavaged with large volumes of saline; if the entire placenta is retained, it is difficult to retrieve the saline as the placenta clogs tube

Follow progress of uterine involution by physical examinations, CBC, fibrinogen concentrations, rectal examination and ultrasonograpy

Commonly used drugs in the post partum mare for retained placenta and metritis
6. Exercise