Experts address keys to the foaling examination
With excellent veterinary care ... foals will get past any early disease.
Part one of this two-part series on foaling discussed the initial neonatal exam and the importance of monitoring the foal's suckling ability. Part two continues the discussion with a look at monitoring the foal's health in the hours, days and weeks after birth.
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Before beginning the systematic exam, consider the effects of the birthing process on the foal, suggests Laurie Metcalfe, DVM, Rood & Riddle Equine Hospital in Lexington, Ky. Was it a normal foaling? Did the mare have any abnormalities? Were there any signs of prematurity or dismaturity?
"In central Kentucky, it is precisely known when the mare was bred, so we know whether a foal is on time or early," says Metcalfe. Some foals are dismature in-utero. They still have fine hair coat, but may show tendencies toward sepsis and other issues of prematurity. Any issues of dismaturity as well as any congenital abnormalities should be noted. For example, the foal might be bright and alert but unable to get up because its tendons are still contracted.
Consider the posture of the foal. Is it lying laterally? Sternal recumbency is critical in newborn foals especially if they have any respiratory issues. The gait of newborn foals should be hypermetric with a base-wide stance. "The Merck Veterinary Manual" states: "Extreme hypermetria of the forelimbs, usually bilateral but occasionally unilateral, has been observed in some foals associated with perinatal hypoxic/ischemic insults, but this gait abnormality usually resolves without specific therapy within a few days. Spinal reflexes tend to be exaggerated. Foals also exhibit an exaggerated response to external stimuli (e.g., noise, sudden visual changes, touch) for the first few weeks of life."
"Once I realize that a foal is bright and alert and not having any immediate issues, I will go over them by body system," Metcalfe says. First, monitor the heart. A continuous PDA (patent ductus arteriosus) "washing machine" murmur is normal for the first 72 hours, so that is of little concern. Listen to the lungs to make sure there is good air movement.
"I get a little more concerned about silent lungs than I do about harsh lungs. I like to make sure that its respiration is good. I get more concerned about slow respiration than I do about dyspnea."
It is important to have a systematic approach to the physical examination so all body systems are assessed. "I start at the head and look at its gums and eyes. Are they sunken? Are they dehydrated?" asks Katherine MacGillivray, VMD, Dipl. ACVIM, Hagyard Equine Medical Institute.
The GI tract should be functioning well. Foals should nurse several times per hour for brief periods. Often after the foal passes the initial meconium, it can be difficult to find the foal's manure in a large stall. Therefore, listening to intestinal sounds and monitoring the size/distention of the abdomen are important.
Colic in the foal can be due to several different conditions not all related to the intestinal tract. Common causes of colic include meconium impactions, rupture of the bladder and diarrhea. There also are rare congenital intestinal diseases in which little to no fecal matter is passed.
Check the umbilicus to ensure that no infection is brewing. Septicemia is blood-borne from bacterial infection via the mucosal membranes of the umbilicus, GI tract or respiratory tissues, and might localize in the foal's joints. Some infections develop in-utero from passage across the placenta and are present at birth. Clinical signs might be subtle at first and progress quickly, leaving the foal quite sick. Symptoms include depression, inability to nurse, diarrhea and excessive sleeping. The infection commonly presents as hot, enlarged joints.
Once the circulatory, respiratory and GI systems are checked, Metcalfe performs a methodical examination of the musculoskeletal system. Evaluating the ribs and joints is especially important.
"It is important to check for fractured ribs because we see a fair number of those, some from people intervening during the foaling process," MacGillivray says.
The foal might be injured, and ribs might be fractured if the mare is not relaxed or from other trauma during the birthing process. Often foals do not have overt fractured ribs right at birth. They are probably green-stick. Then as they move around and act normally, they might displace those ribs (which were mildly fractured early on). The broken ribs might be painful, and the foal might not want to nurse. They often develop meconium impactions, and it might be uncomfortable to defecate.
It is necessary to perform a thorough ophthalmic exam immediately because some foals are prone to sepsis, etc., and might show a corneal ulcer or entropion. They might not have the neurologic ability to blink and protect themselves.
As the body systems exam proceeds, it is important to pay attention to neurology and decide what's normal and what's abnormal. Newborn foals have an ataxic look, so discerning normality might not be easy. Some foals that have neurologic issues will also have a head-tilt, which is a clue to such problems. Some foals that are premature, dismature or have a hypoxic insult might show signs of neurologic deficits as far as the cranial nerves or peripheral nerves.
Some foals will have a laryngeal nerve deficit. When they nurse, milk comes out of their nose, which is a sign of possible nerve damage, especially if they don't otherwise have a cleft palate or other reason for an inability to nurse properly. Sometimes a foal is colicky because its GI tract is not fully developed and might have ileus, or the neurologic supply to its gut is not adequate. Ileus is an absence of gastrointestinal motility with subsequent gastrointestinal distention. Possible causes include electrolyte abnormalities, impaired autonomic nerve function or inflammation caused by peritonitis or enteritis.
As part of her assessment of a sick foal, MacGillivray often uses an ultrasound exam, which typically is used to evaluate the abdomen and lungs and occasionally the heart. She asks: Is the bladder intact? Is there distention of the small or large intestine? Is there any free abdominal fluid?
The ultrasound can be used several times a day. It has become an excellent diagnostic tool, along with blood work, to help determine what is going on with a newborn foal. As ileus can be particularly life threatening in the neonate or weak foal, abdominal ultrasound assists to identify a gas- or fluid-distended bowel.
A few days to a few weeks
"In a couple-day-old foal you should not really see much trauma. However, infection can occur at any time up to a couple of weeks after birth, whether blood-borne sepsis, umbilical, lung or joint infection," MacGillivray notes.
By day two or three, foals should be pretty strong, outside running around. A few days after they are born, some foals might get a fever and/or big joints, so an examination to identify septic joints is warranted. If a foal still has ataxia after two to three days, it is a concern. Some of these foals will circle in one direction or nurse from the mare only on one side, which can be a red flag for neurologic deficit.
By the two-week range, all is relatively safe. At 2 weeks to 4 weeks of age, foals can develop scours, which can be due to a variety of causes. Foal heat diarrhea commonly occurs during the mare's first heat at nine days to 10 days. With foal heat diarrhea, the foal remains bright with an excellent appetite and usually does not have any fever. There are also infectious causes of diarrhea such as Rotavirus, Clostridium spp and Salmonella.
Salmonella has been a huge concern within the equine population. Foals can become infected from the mare or other horses that contaminate the environment. These horses, including the mare, can shed Salmonella despite not having any clinical signs (diarrhea, fever, malaise) attributable to the infection. One mare or foal shedding Salmonella can lead to illness throughout the barn due to contamination of the environment via hand-and-foot traffic through the barn or hospital.
Rotavirus can cause diarrhea. Like Salmonella, Rotavirus might be picked up in the environment or from contamination from horses or worker's hands or clothing. If farms vaccinate, foals might not be affected until they are a bit older, up to 2 months to 4 months of age.
Some farms choose not to vaccinate, or if there is a break in their protocol, foals might be affected at a younger age. The critical sign is whether the foal looks sick. If it has some diarrhea, is nursing, does not have a fever, is strong, active and seems OK, it might not require therapy.
It is important to check the animal's blood work to assess electrolyte status and metabolic status. Many foals with transient diarrhea require minimal to no therapy other than monitoring and perhaps a probiotic. If they are running a fever, appear sick or are not nursing, more involved therapy is usually indicated. Diarrhea can make the foal very sick. Bacteria can get into the blood and cause distant infections in other body systems such as joints, lungs, brain or kidneys.
"We see some Clostridium perfringens, and it may cause disease in foals, although there is continued debate if it is the primary cause of disease in the foal," MacGillivray says. "Some farms seem to have an annual problem with it, usually when foals are a couple of weeks old."
Teamwork is key
In the central Kentucky area, DVMs are fortunate to have farm personnel that commonly recognize problems before a veterinarian is able to get to them. Querying the farm personnel usually is of assistance, because they know if the foal is nursing, has defecated, urinated, etc. Foals often are considered valuable, and there is no hesitation to send them to the clinic for medical or surgical therapy.
In central Kentucky, farms have highly trained personnel allowing veterinarians to treat foals at the farm. If they want to put in an indwelling catheter or a nasogastric tube because the animal is not nursing and can't get up, the farms have the personnel and ability to care for them. Veterinarians in the Bluegrass State are fortunate to have people who not only have experience working with horses and foals but the desire to care for them at the farm. In other parts of the country, it can be difficult to manage these foals on the farm due to lack of facilities and/or personnel.
Kentucky veterinary clinics often are equipped for foal intensive care if necessary. At Hagyard and Rood & Riddle, there is a climate-controlled foal-care facility that's heated in the winter and cooled in the summer.
Oxygen is available for continuous administration. Fluid infusion machines are available for administering intravenous fluids and total parenteral nutrition (TPN). Beds with Temperpedic® mattresses are available for recumbent foals to minimize pressure sores. At both these referral hospitals, veterinary technicians are stationed in the facility 24 hours to care for hospitalized foals. In addition, at Hagyard, a veterinarian remains at the hospital overnight to monitor patients. If the foal is unable to nurse or is not allowed to nurse due to other conditions, the mares are milked to maintain milk production. Foals are monitored at all times by veterinarians and technical staff.
These referral hospitals house all types of sick foals, from PAS foals, septic foals, weak foals and those with respiratory disease. The facilities are kept clean, and if a foal develops diarrhea, it is moved to another barn for continued care to minimize cross-contamination to other hospitalized cases. Biosecurity has become an intense process at these facilities due to the prevalence of Salmonella within the equine population.
With excellent veterinary care and good farm observation and teamwork, foals will get past any early disease and once healthy, will thrive and grow as they should.
At the University of Minnesota, Stephanie Valberg, DVM, PhD and her colleagues work with specific muscle issues of foals such as white muscle disease, which includes glycogen branching enzyme deficiency (GBED) and polysaccharide storage myopathy (PSSM).
White muscle disease was common during the 1970s and early 1980s, when nutritionists and veterinarians were less aware of the selenium and vitamin E requirements of young foals. Now that many owners are feeding fortified feeds to their mares and foals, fewer cases are believed reported. Sometimes, with a difficult birth, foals might have mildly elevated muscle enzymes, and as newborns, it is common to also assess blood parameters for birth hypoxia. Elevated muscle enzymes indicate muscle damage, possibly due to nutrition issues, i.e. selenium or vitamin E deficiency. If in doubt, foals are given IM selenium and vitamin E if they have elevations in muscle enzymes.
"One injection doesn't hurt, and we can test for these nutrients to see if there is evidence in the blood of these deficiencies," Valberg says.
If foals have elevated muscle enzymes, the other possibilities, especially in Quarter Horse foals, are glycogen branching enzyme deficiency and polysaccharide storage myopathy. There is a difference in the way foals with these issues present.
Foals with PSSM are usually stiff and sore, have very painful firm muscles and will develop coffee-colored urine because of the high-degree of damage to their muscles.
They are identified by a muscle biopsy. Those foals require a lot of attention and treatment to try to get them over their episodes of muscle pain and cramping as well as special dietary management in order to try to bring them along.
The owners of the animals need to be aware that as adults, those foals are potentially going to have problems of tying-up if they don't manage their diets early.
Foals with GBED, a fatal disease, are sometimes born weak, aborted or dead. Those GBED foals born alive might have a very low body temperature and be weak enough that they can't stand up to nurse.
Such foals might get referred to veterinary hospitals because they don't seem as lively as other foals. They need a lot of intensive care, but this genetic defect will cause them to die.
It is important to test for GBED to identify it early. GBED foals often will have low blood sugar and might collapse intermittently. If they are nursing the mare, they can look normal, yet with exercise they can fall over and die.
"We developed a genetic test for GBED," Valberg states. As a dominantly inherited disease, about 9 percent of Quarter Horse mares carry it. Valberg and colleagues estimate that at least 3 percent of abortions are due to GBED. "We think it is very important to begin testing Quarter Horses and Paint broodmares for GBED and to avoid breeding a carrier of GBED to another carrier because there is a 25-percent chance that a foal could have GBED," Valberg cautions. The problem with the condition is that foals cannot make normal forms of muscle glycogen in the liver, heart or brain. They develop an energy deficiency, and the tissues are unable to function properly.
With PSSM, foals make too much glycogen and store excessive amounts in their tissues. It somehow interferes with their energy metabolism, and causes muscle cell necrosis. If a DVM decreases the amount of sugar in their diets, he or she can decrease the amount of energy going into their muscles and sometimes are able to manage them fairly well if intervention begins at an early age.
At University of Minnesota, Valberg and her colleagues are trying to identify genetic diseases and figure out what the predisposition is to some of them. With PSSM, they are working to determine a genetic test to identify it in mares. It is a dominant trait, so it only takes one parent to pass on the disease. Some of the foals that are dying might have inherited a copy of the gene from both parents, and therefore in those cases it is more severe than if the foal inherited the disease from one parent.