Spring foaling can be exciting, stressful time

By Dr. Glen Jensen, DVM

The months and weeks that lead up to foaling season can be exciting in the anticipation of the new baby. Unfortunately there are some occasions that may lead to disappointment. Late term abortions, weak or dummy foals, foaling difficulties, or a sick foal can all be devastating to the owner. While these problems are not very prevalent we do see several cases every year. Early preparation, good vigilance, and a quick response can often make the difference between a live healthy foal and one that is not.

Preparation really begins almost a year before, when the mare is bred. Good records will help to determine the estimated foaling date. An early ultrasound examination can detect twin pregnancies and confirm the gestational age at that time. Twins are a major cause of abortions, and even if an abortion does not occur there is a high probability that the mare will have problems foaling. Then if the foals are lucky enough to be born alive only about 50 percent will survive. When twins are diagnosed early during gestation it is a relatively easy condition to successfully manage. One of the conceptuses is destroyed allowing the other to continue to term.

Signs of a possible impending abortion are early lactation, vaginal discharge, maternal systemic illness, larger than normal abdominal size, suspected twinning, overdue pregnancy and a previous poor outcome of parturition. Mares with these conditions or a history of these conditions should be examined by an experienced veterinarian who can perform the necessary diagnostic procedures. A high risk mare should be examined monthly starting during her eighth month of pregnancy. If problems are identified then closer monitoring will be needed.

Possible problems that may be identified include: placentitis, twins, uterine torsion, hydrops, twisted umbilical cord, prepubic tendon rupture, congenital defects, and uterine inadequacy. During the exam the fetus and uterus are ultrasounded both transabdominally and trasrectally. Mammary secretions, if present, are analyzed for calcium, sodium, and potassium levels. Through the use of ultrasound measurements and laboratory data it is possible to find and treat or support many of these late term pregnancy diseases. While ultrasounding the fetus a heart rate is obtained and the fetus is evaluated for tone and viability. The thickness of placenta is measured along with the uterus and is examined for separation or pockets between the placenta and the uterus.

Placentitis is the cause for about 30 percent of late term abortions. Some of these abortions may only be seen as an early foal or a foal that is born and never does very well until it dies within a few days after birth. The infection is usually an ascending infection and may be caused by normal bacterial flora of the reproductive tract. The good news is that if detected early and treated aggressively over 85 percent of these foals can be born alive and viable.

Most horse owners have either had or know someone who has had a foal that is referred to as a “dummy foal” or a foal that is neonatal maladjustment syndrome. The medical term for this is hypoxic-ischemic encephalopathy. The cause is loss of oxygen or low oxygen levels for an extended amount of time at or near the time of delivery. These foals may have mild behavioral abnormalities with no interest in the mare or wanting to suck, aimless wandering, obsessive licking, tongue protrusion, abnormal jaw and facial movements to severe problems such as seizures. This is one of the reasons that many owners want to watch the mares closely with monitoring equipment near the time of parturition.

Dystocia or difficult birth is a true emergency for the mare. Unlike cattle and some other species, once the second stage of parturition begins, the mare is visibly having contractions, the placenta begins to detach from the uterus. A mare will usually have the foal within two hours from the beginning of second stage labor or when the first water breaks. Mares that take much longer than this begin running the risk of a dummy foal or one that is born dead.

Successful intervention in late term problems in the mare, have a much higher probability of a positive outcome when addressed early and treated aggressively. Dystocias in equine is not a time to give it a few hours and just see what happens. Early signs of impending parturition, like milk production, a few weeks to months before the due date, needs to be taken seriously. An examination for a proper diagnosis and treatment to stop a possible abortion needs to be quickly made. (Doctor Jensen is with Emery Animal Health)