We read everyday of human babies being born very early but surviving nonetheless. It’s different with a foal, where a birth as short as a week before the foal has physically matured enough may cause life-threatening problems.
Any foal born before 300 days of gestation is premature and unlikely to survive. Apparently normal foals have been born after as little as 305 days, but a gestation between 300 and 320 days is likely to result in a premature foal. Although foals born after 320 days are technically mature, Mother Nature doesn’t obey rules, and it’s possible to have a foal with features of prematurity, or dysmaturity, in longer gestations. The average normal gestation is 340 days.
Mares that have carried their pregnancies toward the short or long end of the spectrum of ’normal’ – 320 to 360 days – will tend to repeat the pattern with each foal. However, studies have shown the sire can influence gestation length, too, so even this isn’t reliable.
The point to remember is that a mare showing signs of impending delivery between 300 and 320 days should be considered at high risk of delivering a premature/dysmature foal. You need to be alert to this possibility with any pregnancy.
By far the most common cause of premature delivery of a foal is infection, either a viral infection like rhinopneumonitis/herpes, or a bacterial or fungal infection of the placenta. A twin pregnancy, problems with the foal itself, partial uterine torsion and umbilical cord abnormalities are less-common triggers.
It’s better to head off a premature delivery if you can rather than deal with it after the fact. Mares in late pregnancy tend to be somewhat uncomfortable, even mildly colicky, sluggish and go off feed, so it can be difficult to tell if something is bothering them. A more reliable indicator is if the mare begins to bag up, or even leak milk, ahead of schedule.
Vaginal discharge may also be present. If you see this, or even if nonspecific changes in the mare are setting off your ’sixth sense,’ it’s best to get her checked. An ultrasound can be done to check for problems with the uterus/placenta, some of which may be headed off.
Handling The Preemie
A premature foal isn’t just small, he’s thin with little body fat and often weak. The coat is typically extremely short and silky, and his ears may flop at the tips. Tendon laxity/weak tendons may be evident when he stands, and angular limb deformities can be present at birth or develop, worsening rapidly if the small bones of the knee and hock aren’t completely calcified. If the lungs aren’t mature enough, the foal may have trouble breathing.
The first thing to do with a premature foal is get your vet. The decisions about treatment will largely depend on how premature the foal is and how well he copes in the critical first hour or two of life. Except for clearing the airway, don’t interfere with the mare’s bonding with her foal immediately after delivery. The next few days to weeks may be stressful for them, with a lot of human intervention, so make sure they’re well imprinted.
Don’t be in any rush to cut and tie the cord or force the mare to get up, which may then break the cord. The little guy needs all the help he can get. Do use several warm, thick towels to dry him well. Temperature regulation in premature foals is often poor, and hypothermia a real possibility. Protect the foal from direct drafts and consider heat lamps. However, be extremely careful with heat lamps, as they can be a fire hazard, especially in a dry barn full of hay and straw. Don’t ever leave them on unattended or place them where the mare or foal can touch them.
Keep track of the time of foaling and if the foal meets the post-foaling milestones for normal behavior (see sidebar below). If the foal has not gotten to his feet in two hours, don’t force it. He may be too weak or the musculoskeletal system too poorly developed to support him well. Hopefully, your vet will be there soon.
If not, begin to milk the mare’s colostrum out into a clean container so that it can be tubed into the foal. Premature foals develop low blood sugar levels rather easily, which makes their weakness even worse. Tubing the foal will be one of the first things your vet will want to do if the foal has not been able to nurse.
Your vet will give the foal a complete exam to check for any trauma from foaling, reflexes, nervous system status, lung maturity, musculoskeletal development and all the other routine foal checks as well. The vet may also want to examine the placenta for any signs of abnormality that might indicate an intrauterine infection. If so, the foal will need a course of antibiotics. X-rays will likely be done of the knees and hocks to see if the bones are fully calcified.
Depending on the findings, your vet will give you an outline of what special measures may be needed to support the foal. Very premature foals may need intensive care in a hospital setting, while others can be managed at home. While the possibility of a premature foal is a real worry, the odds of survival are much higher than they used to be.