Page 86 - Speedhorse October 2018

The history of the mare is a major factor in what should be considered as a high-risk pregnancy.
Some mares develop problems during preg- nancy that put the fetus at risk for abortion or premature delivery. Chances for survival for these foals can often be improved if the problem is discovered early and the mare given proper treatment and monitoring.
MARES AT RISK
Peter Sheerin, DVM (Nandi Veterinary Associates, New Freedom, Pennsylvania) says most of the mares that get monitored as a high risk pregnancy are mares that have placentitis or have had placentitis in the past. “If they’ve had this problem in the past there is more than 50% likelihood they will have it again,” he says.
Other mares that should
be monitored are mares that
have had uterine artery bleeds in the past and were rebred. “Mares that have had surgery—whether colic surgery or something musculoskeletal—also need
to be monitored because there is always some stress associated with surgery,” he says. The history of the mare would be a major factor in what we’d consider as a high risk pregnancy.
If the mare had a uterine torsion during pregnancy that had to be corrected, she would become high risk and need monitoring because of potential damage to the uterus. “When it’s twisted, the blood supply is compromised and the uterine tissues tend to get more edematous. After the torsion is corrected—either surgically or mechanically by rolling the mare—she would fall into the high risk category and we’d want to monitor the foal,” he explains.
HIGH RISK
Pregnancies in Mares
by Heather Smith Thomas
“If the mare had colic surgery, depending on how recently she had the surgery, we worry about the integrity of that abdominal incision. The stress and pressure during labor may compromise it. The big- gest thing that could impact this is how well healed
it is. Obviously the longer it’s been since the surgery, the less risk there might be. If the surgery was recent, those mares would likely need to wear a belly band
to help support that incision. There are commer- cial belly bands available, to try to hold everything together while she’s foaling,” says Sheerin.
Any mare with a musculoskeletal problem would be considered high risk. “If she is unsound or has bad stifles, for instance, she may have trouble getting up and down, especially as she gets heavier in foal. She may not want to lie down to foal (and you’d need to be there in case she foals standing up) and if she does lie down she might not be able to get up,” he says.
Older mares in their late teens or early 20’s that have never been bred before and are carrying their first foal, or any older mare, should also be moni- tored. “As they get older, mares are at a higher risk to have uterine artery bleeds, even if they haven’t had a lot of foals. The composition of the arteries changes and they become more brittle, and may rupture easier,” says Sheerin.
Any mare that has had health problems or some kind of chronic problem would also be high risk. “This would include mares that are currently foun- dered or having episodes with laminitis. The stress and pain from any health problem could be a risk factor,” he explains.
“A foundered mare may be uncomfortable stand- ing up and may be lying down all the time. We worry about the impact that might have on blood flow to the uterus, and how that might impact the fetus,” he says. Any abnormal condition in the mare will have some kind of influence but we don’t always know how much, until she foals.
Peter Sheerin DVM
of Nandi Veterinary Associates in New Freedom,Pennsylvania.
Heather Smith Thomas
84 SPEEDHORSE, October 2018
EQUINE HEALTH