Pediatrics

By H. Steve Conboy.

Pediatrics is the branch of equine medicine that deals with health of the foal from birth until weaning. To successfully raise a foal, it is essential to have a basic knowledge of the normal anatomy, physiology and behavior of the foal. It also helps to understand the terminology that describes both normal and abnormal conditions that affect foals. In most cases the diagnosis and treatment of foal diseases is best done by the veterinarian but the horse owner needs to recognize early signs of illness in order to know when to call the vet.

Unlike the newborn human, a foal is born without protective antibodies in its circulation. The foal must acquire passive immunity to disease by absorbing antibodies from the mare's first milk, colostrum, by way of the digestive system. The reason for this is that the equine placenta will not permit the passage of antibodies from the mare's circulation to the fetal circulation.

Passive transfer of antibodies to the foal occurs during the first 24 to 48 hours following the foal's birth. After this time the colostral antibodies diminish significantly, as does the foal's ability to absorb them.

It is easy to understand why it is so important for the newborn to receive the antibody-rich colostrum soon after birth. Veterinarians and horse owners have learned to take advantage of this mechanism of passive transfer by boosting the mare's antibody titers with certain vaccines a month before foaling to provide an adequate supply of antibodies in the mare's colostrum.

Following a foal's birth,treat the navel stump with an antiseptic (a 50-50 mixture of strong iodine and glycerine is excellent). The stump should be treated by dipping it in this mixture once a day for a minimum of 5 days to prevent infection and to encourage proper drying of the navel cord stump.

The neonate (newborn) foal should be very active shortly after birth and will struggle about the stall before it is able to stand, which usually takes 30 minutes to an hour. After the foal is on its feet, it should begin looking for the mare's udder to nurse. It is not uncommon for the foal to make attempts at nursing the mare's flank or leg before it actually finds the teats. In most cases, the foal will have nursed in 2 to 3 hours after birth.

A veterinarian should examine the newborn foal to check its state of health and recommend any special care or treatment needed.

Abnormalities, Illness

Musculoskeletal abnormalities are very common in newborn foals. Some require immediate therapy, others only need observation as they will correct spontaneously with time. Foals that have severely contracted tendons and scoliosis (lateral curvature) of the spine contracted foal syndrome respond very poorly to therapy and generally require euthanasia. Mildly contracted tendons without skeletal defects respond to casting or splinting. Foals born with very weak tendons that allow hyperextension of the ankle and carpal joints improve dramatically with controlled exercise.

Umbilical and scrotal hernias occur frequently and do not usually require immediate attention. Most of these hernias will disappear as the foal develops. If they persist at weaning age, surgical correction may be required.

As mentioned earlier, it is important to recognize the symptoms of a sick foal so proper therapy can be started. Usually the first sign of any illness in the foal is its failure to nurse, which is indicated by the mare's udder being full and distended. When this is observed, the foal's temperature should be recorded with a rectal thermometer. The foal's normal temperature is 99.4 to 101.5 F.

A foal with a significant fever usually will be depressed and inactive. A healthy foal generally will jump to its feet when approached. The normal foal's respiration is usually rhythmic and thoracic. Panting, pumping or breathing abdominally is abnormal unless the foal has been running. Following are brief descriptions of several diseases and conditions that affect foals.

Rhinopneumonitis. Occasionally a foal will be born to a mare that experienced equine herpes virus-I during pregnancy. Usually the fetus will be aborted during the later part of pregnancy but when the fetus is carried to term, it is born very weak and is unable to stand or nurse. Despite the most diligent care, these foals fail to survive more than 24 to 48 hours. There are several vaccines that prevent this disease but they must be given during the mare's pregnancy.

Sleeper or Septic Foal. This condition is seen in the neonate and is caused by a bacterial septicemia. The foal is lethargic, reluctant to nurse, and has a moderate fever. Aggressive antibiotic therapy and intensive nursing care is required in treating this condition. The prognosis is guarded but treatment is often successful.

Neonatal Isoerythrolysis, a condition often referred to as the jaundice foal syndrome, occurs when the mare develops antibodies against the foal's red blood cells (RBC's) and the foal is allowed to nurse the mare's colostrum.

Symptoms include jaundiced (yellow) mucous membranes and sclera (white of the eye), listlessness, yawning, accelerated heart rate and respiration, weakness, and occasional red urine. The primary clinical symptoms are anemia and jaundiced plasma.

In the very acute form, the foal may be found dead several hours after a normal birth. In the less acute form, the physical symptoms usually are noticed during the first 2 to 4 days after birth.

This condition can be prevented by not allowing the foal to nurse the mare's colostrum when it contains RBC antibodies.

There are several ways to identify these antibodies. The most reliable is to blood type the mare and stallion prior to the birth to reveal any potential incompatibility, and then to screen the mare's serum for RBC antibodies shortly before foaling. Another method tests the mare's colostrum with the foal's RBC's to identify the presence of RBC antibodies.

Treatment for this condition often requires a blood transfusion to replace the foal's damaged RBC's.

Ruptured urinary bladder is a condition seen on the third to fifth day after birth. The foal usually is colicky and reluctant to nurse. The abdomen generally appears pendulous and distended. The only treatment for this condition is surgical repair of the bladder. When diagnosed early, the prognosis is good for complete recovery.

Meconial Impaction. The neonate frequently is plagued with severe constipation caused by dry fecal balls that become lodged in the rectum and small colon. This condition causes the foal to strain in an effort to defecate, with negative results. As the condition progresses, the foal will show signs of abdominal pain by getting up and down.

Digital palpation of the rectum will usually reveal hard large fecal balls. Treatment consists of soapy water enemas and intestinal lubricants until the fecal balls are softened and passed.

Patent Urachus. The umbilical stump contains the urachus (the urinary canal of the fetus) that was responsible for transferring urine from the fetal bladder to the placenta. Very soon after birth, it seals and is no longer functional. If it fails to seal, urine will continue to leak from the bladder. Usually the condition is corrected by dipping the cord daily in an iodine antiseptic. If this therapy fails to seal the canal, the opening can be cauterized with silver nitrate or phenol. It usually is not advisable to clamp or ligate the stump.

Omphalitis. When bacteria invade the umbilical cord, an abscess occasionally develops creating a lemon-size swelling in the umbilical area. This is not to be confused with an umbilical hernia that is soft and easily pushed into the abdomen. Infection of the umbilical cord is very serious and demands antibiotic therapy. Failure to treat this condition properly can lead to more serious systemic infections.

Septic arthritis occurs when bacteria invade a joint and establish infection. Cause of this disease usually is a combination of the foal's failure to receive adequate antibodies from the colostrum and a bacterial invasion via the umbilicus. However, the bacteria can also invade through other routes such as the respiratory system.

Clinical symptoms are a painful, hot, swollen joint. This condition requires immediate veterinary attention that will include culturing of the joint, systemic antibiotic therapy, and lavage of the affected joint. Many cases respond rapidly to this therapy but others fail to respond and eventually are euthanized. Septic arthritis usually is seen during the first 3 months after birth.