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Common Problems with Foals
By Dr. Allison Forbes
Everyone’s expectation of their foal is this: bright, happy, nursing well, and providing us endless entertainment that we can post on FaceBook, Instagram, and Twitter.
Unfortunately, foals don’t always go by the book. The once bright and happy foal you had in the morning is now laying down a lot and not nursing. The mare and foal bond seen yesterday seems to have disappeared. You can tell that something is just not right with your foal. The following are common problems we see with neonates:
Maturity – PRE, DYS, and POST
It is important to have an idea of your mare’s foaling date. Foals can be born premature (less than 320 days of gestation), dysmature (born during normal gestation length, but small and showing premature clinical signs), or post mature (in between 340-360 days of gestation). Premature foals have domed heads with floppy ears. Their hair coats are typically very silky, and their tendons are very lax. They also have what we call “incomplete ossification of cuboidal bones.” This is when the bones in the knee (carpus) and hock (tarsus) have not developed enough and is a poor prognostic indicator. If your vet is suspicious that your foal is premature, radiographs are typically taken of the front and hind legs. Premature foals are also at higher risk of failure of passive transfer, or FPT. This is because they are so weak and stressed that it is difficult for them to have the strength to stand and nurse. Dysmature foals present similarly to premature foals, but have a normal gestation length. Postmature foals are typically very large, may have contracted tendons, and often cause a dystocia (difficult birth) due to their size. The overall prognosis for premature, dysmature, and postmature foals is good but requires intensive and proper care.
Sepsis, or septicemia, is infection in the blood. Maternal illness during pregnancy, failure of passive transfer, or any abnormality in the foal can lead to sepsis. Typical routes of infection are through the gastrointestinal tract, umbilicus, respiratory tract, or wounds. Early on in sepsis, neonates may appear depressed with a decreased suckle reflex. Foals also can have injected, or dark red, mucous membranes, petechia (small areas of hemorrhage), uveitis, and trouble thermo regulating. Blood work consisting of a CBC (complete blood count), chemistry, lactate, and glucose is performed. A blood culture is obtained as well, and the neonate is started on antibiotics and other supportive therapies. If caught early, the prognosis is fair to good. However, once the disease progresses, the prognosis decreases.
Hypoxic Ischemic Encephalopathy (HIE) or Perinatal Asphyxia Syndrom (PAS)
These foals are known commonly as “dummy foals.” They appear normal after birth, but within the first few to 24 hours, become quiet, weak, forget or don’t know how to nurse, and don’t form a strong bond with the mare. For instance, if you remove the mare from the stall, the correct response is to follow the mare. “Dummy” foals will typically just stand in the stall and make no effort to stay with their dam. If your veterinarian is suspicious of HIE, supportive therapy consisting of careful IV fluid administration and plasma may be considered. Hypertonic saline, DMSO, Magnesium, Vitamin C, and Vitamin E may also be administered. The prognosis for these foals, if caught early and treated aggressively, can be good to excellent, with up to 80% survival rate. However, the prognosis drops with concurrent illness, such as sepsis, or if the foal was premature.
Failure Of Passive Transfer (FPT)
It is extremely important for your foal to be standing and nursing soon after birth. The foal needs to nurse in order to receive colostrum, or milk with high immunoglobulins, which supports their humoral or innate immune system. Colostrum is the first milk that the foal receives from the mare. This aids in protecting foals from disease the first few months of life while their adaptive immune system develops. Without colostrum, foals are extremely susceptible to infections and have a decreased ability to fight off disease. Exposure to pathogens or illness can then lead quickly to a life threatening situation. Mares can leak colostrum before birth, and can continue to leak after birth. So, if your foal is NOT up and nursing, contact your veterinarian right away. Depending on your location, the foal can supplemented with colostrum orally or give intravenous immunoglobulins (plasma). FPT foals are more likely to become septic.
Bladder rupture during the birthing process can occur, which allows urine to leak into the abdomen. Colts appear to be more predisposed than fillies. Neonates with ruptured bladders will strain to urinate, dribble urine, and stand with their legs stretched out. A fluid wave may also be felt on palpation of the abdomen. A very good diagnostic test for uroperitoneum is comparing blood creatinine to abdominal fluid creatinine. A ratio of greater than or equal to 2:1 is considered diagnostic. The first round of therapy is aimed at stabilizing the foal, and then either surgical or medical management can be considered. Prognosis is variable, as these foals can be septic as well.
Neonatal Isoerytholysis (NI)
This is a disease that causes jaundice (yellow-colored mucous membranes) and anemia (low red blood cells) in foals. There are several prerequisites to developing NI: 1) The foal must inherit the trait from the sire, and express an erythrocyte antigen that is not possessed by the mare, 2) the mare must become sensitized to the incompatible antigen and produce antibodies to it, and 3) the foal must ingest the antibody containing colostrum within the first 24 hours of life. The foal becomes weak and anemic after ingesting the antibodies in the mare’s colostrum, which causes their immune system to destroy their own red blood cells. These foals are born normal, but within 6-72 hours become: lethargic/weak, white or yellow mucous membranes, increased heart rate, increased respiratory rate and effort, and have a decreased suckle. Appropriate treatment including proper nutrition and meeting the metabolic demands of the neonate is extremely important. IV fluids are typically administered, and liver and kidney values monitored. A blood transfusion may be necessary. Prevention is key with NI; if a mare has had a foal with NI in the past, she will most likely have another foal affected. If a mare tests positive, the foal should be muzzled and the colostrum withheld until the colostrum itself tests negative. Alternative colostrum should be for at least the first 24 hours until the foal’s gut closes.
To reiterate, call your veterinarian at the first sign of concern. Prompt veterinary intervention and care can lead to a better outcome and prognosis for your foal!
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