While animals of many species routinely give birth to multiple healthy offspring from one pregnancy, horses are not designed to nourish two fetuses and produce viable twin foals. Double pregnancies put the mare and both foals at risk, and good outcomes are rare.
In some mares, a placental infectioncan interfere with proper functioning of the placenta, and the result may be loss of pregnancy or premature delivery of the foal.
Dystocia, or difficult delivery of a foal, is more common in three-year-old draft mares compared to more mature mares of the same breeding, according to a study conducted in France.
In horses, spaying is not common, and means removing the ovaries rather than the uterus and ovaries as in dogs and cats. Although owners generally learn to accept that their mares may show some behavioral and personality changes during heat periods, spaying is an option for mares with particular problems.
Uterine infection is one of the most common reasons for infertility, but there are other reasons why mares might fail to conceive, including obesity and equine metabolic syndrome.
Getting mares ready to be bred is not an overnight chore. An owner who is considering breeding a mare needs to begin several months ahead of the breeding season in order to have the mare in the best condition to become pregnant.
Potomac horse fever is not thought to spread from horse to horse, but in pregnant mares, the infection can cross the placenta to affect the fetus.
While most mares are good mothers, it sometimes happens, especially with a first foal, that the mare ignores her baby, won’t let it nurse, or even attacks and injures it. A few management techniques may help an unsure mare bond with her foal.
Mares commonly conceive twins, though the chances are not good that they successfully carry both fetuses to term and deliver healthy foals. A recent study examined the results of twin reduction in over 100 mares.
The most common cause of late-term abortion in mares is placentitis, a term that describes an inflammation of the placenta. Nocardioform placentitis is somewhat less common, but a significant upswing in cases occurred in Kentucky two years ago,
|Putting Weight on a Skinny Horse|
|Swollen or Filled Legs: What’s Wrong With Your Horse?|
|Stabilized Rice Bran–Just the Facts, Please|
|Feeding Oil to Horses: Choose Wisely|
|Causes of Poor Appetite in Horses|
|High-Quality Milk Essential for Foals|
|How Can Dietary Changes Minimize Skeletal Disease in Young Horses?|
|Airway Disease in Sedentary, Asymptomatic Horses|
|Importance of Detraining Programs for Athletic Horses|
|Feeding Horses in Low Body Condition|