A few helpful reminders for when Foal season approaches.
Vaccinations - be sure to have your mare vaccinated for Rhinopneumonitis (EHV 1) at 5, 7, and 9 months of pregnancy to help prevent abortion due to this herpes virus. Also, a booster of the usual vaccinations (tetanus, encephalitis, influenza, rhino (EHV 4) at 4-6 weeks prior to foaling is important to ensure that good antibody levels will be included in the mares colostrum. The mare should also be dewormed during the last month or at foaling to decrease exposure of the neonate to GI parasites. The vaccination schedules for weanlings has recently been revised because of new information regarding the foals response to vaccination while maternal antibody is still present. Basically, it is recommended that some vaccines be given a little later, especially the influenza vaccine, and that 3 boosters are necessary initially rather than two. See below for more info.
Prediction of foaling - The equine fetus can be palpated or ultrasounded rectally for size for the first few months of pregnancy. However, after 4-5 months, it is no longer possible to feel the entire uterus as it is located beyond the rim of the pelvis down in the more ventral area of the abdomen. So, it is virtually impossible to predict a foaling date after this time. Therefore, knowledge of an accurate breeding date is one of the best ways to help prepare for babys arrival. Mares that have had multiple foals will often follow a similar pattern as far as gestation length. Udder formation will begin in the last month in most mares; however, some do seem to wait until the last minute. In the last week or so, the secretion from the udder will change from a watery substance to a thick sticky form that is the antibody-rich colostrum. The muscles and ligaments around the pelvis and vulva will also relax in the last week. The milk can be tested for electrolyte and/or calcium content; however, this change does not occur until the last few days before parturition. All this information can be used to try and determine when the baby will arrive; however, it is rare to predict very accurately without an accurate breeding date.
Edema or fluid buildup in the skin of the ventral abdomen and udder is normal in most mares during late gestation. If is caused by sluggish circulation similar to that seen in some pregnant women. It should not be more than a few inches thick. More than this may indicate there is a problem with the uterus. Exercise is the best way to minimize edema - daily turnout is best.
Attendance at foaling is always a good idea if possible so that dystocias and weak foals can be identified early. However, moms and babies need some time to bond so as little intervention as possible is best. In other words, try not to "hover" too much, especially with maiden mares.
There are devices available that can be used to alert the owner when foaling is actually occurring. One is a transmitter that is sutured across the vulva. It will send a signal when the connection is broken by dilation of the area during parturition. A baby monitor system used by human parents may also be useful if your barn is within range of these products. One can listen without actually having to be present.
Premature lactation is the loss of milk from the udder during gestation. Milk can be seen dripping or sometimes even streaming from the teats at times. This is not the same as the "waxing" of the teats that is seen just before parturition. The "wax" is a thick substance that just seems to hang at the teat orifice. This usually develops in the last few days before birth. Premature lactation causes loss of colostrum and therefore antibodies, which can leave the foal susceptible to infection. Many times there is no explanation for this problem. The antibody level (IgG) of foals from mares with premature lactation should be measured so that if a plasma transfusion is necessary, it can be given in a timely fashion.
Fescue pasture is known to cause several problems for pregnant mares and neonates: difficult birth, no or minimal milk production and prolonged gestation which then can cause dystocia since the foal is larger than usual. However, removal from fescue for the last 60-90 days of gestation and during the first few months of lactation will prevent these problems. There is also a treatment that works fairly well to induce milk production in agalactic mares that have been on fescue. It is administered orally in the last 2 weeks of gestation and/or for the 10 days after foaling if necessary.
Meconium is the contents of the neonatal foals intestinal tract, the first feces that are passed in the first day of life. Most often, this is a thick, pasty, dark brown to black substance. Ingestion of colostrum helps passage of meconium. If passage is difficult, administration of an enema may be helpful. However, these must be used carefully and with good restraint to avoid damage to the intestinal tract. Repeated enemas are often not advisable without veterinary supervision as the procedure can cause irritation of the rectum. This irritation results in discomfort for the foal characterized by straining to defecate. It can then be difficult to determine whether continued meconium retention exists. Therefore, more is not better in this case.
New Vaccines - You may have heard of some new vaccines or bacterins being given intranasally rather than the more common intramuscular (IM) route. The two currently available are for two of the more common respiratory diseases of horses, the influenza virus and the bacterial infection called "Strangles", due to Streptococcus equi. The theory behind the use of this method of administration is to mimic more closely the way that patients are exposed naturally. Since the organisms are inhaled, the first part of the body to respond is the lymphoid tissue (the equine "tonsils") in the back of the throat. The immune response begins here. The intranasal products are designed to stimulate the production of the same type of antibodies that would result from natural infection and in the same location where exposure occurs. The influenza vaccine is reported to last 6 months, almost twice as long as the IM products. The strangles product is also labeled to last 6 months.
For more information regarding proper care for your mare and foal during this time of year, vaccinations, or any other topic please dont hesitate to give us a call at any time. There is always a veterinarian at the clinic during office hours to provide assistance.