NEWBORNS IN NEED



Supplied by Equine Veterinarians Australia (EVA)

Author: Dr Jane Axon BVSC(Hons)MACVSc DACVIM
Registered Specialist in Equine Medicine.


Health problems need not be a death sentence for a newborn foal, provided they are recognised promptly and treated aggressively.



Over the last fifteen years, there have been considerable developments in the treatment and management of foals born with life-threatening illnesses. Consequently, the old belief that a ‘sick foal is a dead foal’ no longer applies in many cases. Various studies have shown that early recognition of health problems and subsequent timely, aggressive treatment are key factors in achieving a successful outcome. Critically-ill neonatal foals have also been followed through to maturity and have been shown to function equally as well as adult horses that were normal as foals.

As discussed previously in the August/September 2006 issue (Warning Bells - Early Detection of Foaling Problems by Cameron Collins, Vol 28 No 2), the early recognition of what can be described as a ‘high risk pregnancy’ by both the breeder and their veterinarian goes a long way to improving a foal’s chances of survival - even if its health at birth or soon afterwards is compromised in some way. Knowing and being able to detect what is the normal behaviour and appearance of the foal in the first few hours, days and weeks of its life is also crucial. Even very subtle changes in how a foal looks, relates to its dam, and interacts with the environment should be noted and followed up as, even if they turn out to be false alarms, it’s far better to be safe than sorry.

In summary, the foal should stand readily and nurse about every 30 minutes. When awoken, it should get up, stretch then go to nurse. It is very important to bend down and watch the foal nurse, to ensure it has a good tongue seal and no milk is coming out of its nostrils. A sick foal may stand under the mare and look as though it is nursing, but not be sucking from the teat and may have ‘milk staining’ of the face. After nursing, the foal should urinate (if it didn’t prior to nursing), be inquisitive, investigate the surrounding area then lie down to sleep - with those not doing these activities being most likely to have a problem. Some sick foals even ‘forget’ how to lie down and fall asleep on their feet. The faeces of a normal foal, once the meconium (first manure) has been passed, should be soft and yellow in colour.

As well as isolated signs of ill health that can be observed in the mare and foal prior to the birth, during the delivery and after the birth, there are specific diseases and syndromes breeders need to be aware of. Unfortunately, there are quite a few of these that can afflict the newborn foal and which require intensive veterinary care - the most common being Hypoxic Ischaemic Syndrome, prematurity and septicaemia. These conditions can occur together and/or in combination with other diseases - this multi-faceted clinical picture is often the result of an infection or other disturbance within the placenta.

‘Dummy Foal’ (Hypoxic Ischaemic Syndrome)
Neonatal Maladjustment Syndrome, dummy foal, wanderer, barker foal and Perinatal Asphyxial Syndrome are all other names for Hypoxic Ischaemic Syndrome (HIS). This disease is currently thought to be caused by a lack of oxygen supply (hypoxia) and poor blood supply (ischaemia) to the body tissues of the foal, which can occur either during pregnancy, during birth or shortly after birth. The types of clinical signs shown and their severity depend on which organs are affected, as well as on the length of time and degree of the oxygen and poor blood supply. The most common organ systems involved are the brain, kidney and gastrointestinal tract, although any organ can be affected.

Infection or inflammation of the placenta (placentitis), general anaesthesia of the pregnant mare, difficult delivery (dystocia), a caesarian delivery of the foal (C-section) and premature placental separation (red-bag delivery) are all potential causes of HIS. After a foal has been born, problems such as jaundice (neonatal isoerythrolysis), fractured ribs, pneumonia and long periods of lying down (such as may occur with leg problems) can also lead to its development. The disease can also occur from apparently uncomplicated pregnancies and deliveries, so there is still much to learn about it.

The clinical signs of HIS may be present at birth or can develop over the following three days, and will depend on the organs affected.

If the brain is involved, the signs to watch out for can be relatively subtle - like the foal not showing interest in the mare, a poor or absent suckle reflex, an inability to find the udder or a tendency to over-react to normal sights, sounds and touch (hyper-responsiveness). More severe signs that the foal’s brain has been affected are an irregular respiratory rate (abnormal breathing pattern, sometimes including periods of not breathing at all) and convulsions. Abnormal vocalisation, otherwise known as ‘barking’ can also occur, although this is not common.

If the kidneys are affected, the foal may show signs of renal failure including the development of oedema (fluid under the skin that looks like jelly). Gastrointestinal tract involvement may be seen as mild colic, where the foal may kick at its belly or look as though it is straining to urinate or pass faeces. In more severe cases, the foal may display signs of septic shock (very depressed with cold legs and purple gums) or severe colic (rolling on its back and/or falling over with pain), coupled with blood-discoloured diarrhoea.

The treatment regime implemented for a ‘dummy’ foal will, again, depend on which of the organ systems are involved and how severely they have been affected, but the primary aim is to provide support in the way of nutrition, fluids, medications and oxygen until the damaged tissues heal. This may mean the insertion of an indwelling stomach tube (so the foal can be fed until a suckle reflex develops), oxygen being delivered via a nasal tube, the administration of intravenous fluids, providing parenteral nutrition (intravenous glucose, protein and fats) and anti-convulsant therapy.
On a positive note, the majority - over 90%- of HIS foals born with brain involvement recover with appropriate treatment. If other organs are affected, the recovery depends on how badly damaged the organs are, but usually over 80% of the affected foals survive.

Prematurity and Dysmaturity
The reported gestation period for horses is from 320-365 days, however there have been many cases where a normal foal has been produced at 305 or 410 days of gestation - which indicates that all mares have their own gestational length. Thus, a premature foal is one that is delivered before the due date of the mare. If, for example, a foal is born from a mare at 305 days, then it can be considered ‘normal’ if that mare’s normal gestational length is 305 days, but can be considered four weeks premature if the mare’s normal gestational length is 335 days.

Just to confuse the issue, there are also foals known as ‘dysmature’, which means that they were born on time as far as the mare’s normal gestational length is concerned, but look as though they are premature - having the classic signs of a soft, silky coat, floppy ears, a small stature, doming of the forehead and lax (loose) tendons and joints. Dysmaturity generally occurs due to the foal not receiving the nutrition it needed to grow while in-utero, and those born with the above signs have very similar clinicial problems to premature foals.

The most common reason for a foal to arrive prematurely is an infection or inflammation of the placenta (placentitis), but other causes include the presence of twins or the birth being induced on the basis of calendar dates, rather than the foal’s maturity. Occasionally, it is also necessary to remove a foal from the uterus before it has fully developed - such as in a case where a pregnant mare has broken a leg and has to be euthanased.

In addition to the outward physical signs of prematurity, the internal organs of these foals are likely to be under-developed - meaning that often the lungs, gastrointestinal tract, kidneys and glucose regulating systems are not mature enough to handle the world outside the uterus. There is also usually what is known as incomplete ossification of the cuboidal bones, which relates to some small bones in the hocks and knees. As the cuboidal bones are developing, they turn from cartilage into bone - a process called ossification - but, in premature foals, this process is generally still to be completed. Being quite fragile due to their immaturity, these bones are easily crushed and damaged if the foal has too much exercise or gains too much weight too quickly.

Treatment options for a premature foal range from supportive care to very intensive therapy involving being placed on a mechanical respirator, intravenous fluids and parenteral nutrition (providing intravenous glucose, protein and fats). Until there is complete ossification of the cuboidal bones, which will need to be determined by X-rays, the foal should be confined in a stable with the mare. Careful, ongoing monitoring of the legs, to detect any angular limb deformities such as a where the leg turns out (valgus) or where the leg turns in (varus) is also vital and is an area where observations by the owner can be very valuable.

The unborn foal that has been subjected to in-utero stresses - those occuring as a result of a chronic illness of the mare or due to placentitis - tends to have its maturation hastened in some way, often being born with a mature hormone system and lungs. When this has happened, a foal, despite being born prematurely, has a better chance of survival even if born as early as 280 days of gestation. In contrast, a foal removed from the in-utero environment before the final maturation of its organ systems has occurred has, unfortunately, an extremely poor to hopeless prognosis for life.

Septicaemia
A term used to describe a generalised infection within the blood stream, septicaemia is the leading cause of deaths in foals. It can involve multiple organs and the infection can localise in places such as the lungs (pneumonia), gastrointestinal tract (enteritis), a joint (septic arthritis), bone (osteomyelitis) or other areas. The foal can become infected before it is born - via a placentitis - or after birth.

Septicaemia contracted after birth occurs most commonly due to the foal taking in bacteria, which are everywhere in the environment, via its mouth and nose in the first few hours of life - predominantly when finding the udder to nurse or investigating its surroundings. Infection by bacteria can either cause mild signs such as ‘dullness’ and decreased nursing, or can set off a cascade of reactions in the foal - resulting in shock and sometimes, death. It is therefore imperative that the infection is detected early and appropriate aggressive treatment begun. In some cases, however, even this is not enough to save the foal’s life.

Bacterial septicaemia is treated with antibiotics, while intravenous plasma may also be used to improve the foal’s immunity. Other therapies such as oxygen, intravenous fluids and drugs which improve blood pressure and blood supply to the body tissues may be required.

Measures that can be taken to reduce the risk of septicaemia include not overcrowding paddocks and stable complexes where newborns are to be kept, ensuring foaling areas are clean and dry and checking, once the foal has been born, that it has an adequate immunoglobulin concentration (IgG) of greater than 8g/L. The latter involves a simple blood test, performed by a veterinarian, to measure the level of antibodies circulating in the bloodstream.

Meconium Impaction
Meconium, the first manure passed by a newborn, consists of fluid and cellular debris that was swallowed during the foal’s development in the uterus. Brown to olive green in colour and with a firm to hard consistency, it is usually passed within the first 24 hours after birth. The ‘milk’ faeces, that follow the meconium, are softer and orange to tan in colour.

As foals often strain to pass the meconium, a stool softening product in the form of an enema is frequently given shortly after birth - the most common type used in Australia being the phosphate-based Fleet® brand. Great care is needed when giving enemas, as the consequences of incorrectly and over-zealously administering them can, at worst, be a torn or perforated rectum- and subsequent death- or, at least, rectal irritation.

The meconium can become impacted in the rectum, or small or large colon - even if some has already been passed. When this has happens, the foal may show signs of colic - rolling, kicking at its belly or lying on its back - strain to defaecate, wander around aimlessly or go to the udder but not drink. The signs of colic often occur just after the foal has nursed. If an impaction is suspected, veterinary assistance (other than the administration of an enema) may include an oral drench of paraffin oil, intravenous fluids and/or pain relief. Some impactions may need to be treated surgically, however this is extremely rare if the problem is detected and treated early.

Ruptured Bladder
Contrary to what was traditionally thought to be the case, a ruptured bladder or urine in the abdominal cavity (uroperitoneum) can occur in fillies as well as colts, and can happen after birth as well as during the foaling process. In addition, defects in the urinary tract are not only found in the bladder, but can be located anywhere from the tube connecting the bladder to the amniotic sac while the foal is in utero (the urachus) to the tubes from the kidney to the bladder (ureters).

Foals with uroperitoneum are usually normal at birth and can be seen to urinate normally, but some also strain to urinate - producing only small amounts. It should be noted, however, that foals with colic can also display these symptoms. The foal’s abdomen will begin to increase in size as urine starts to accumulate and, because the body is unable to get rid of this, waste products begin to be absorbed. The end result is the development of electrolyte abnormalities - high potassium concentrations, in particular - that can become life threatening.

Surgery is required to repair the defect in the urinary tract, but only after the foal’s electrolyte levels have been stabilised with intravenous fluids and the urine drained from the abdomen. Once the defect is repaired, the foal has a good prognosis.

Jaundiced Foal
Neonatal isoerythrolysis (NI), also referred to as ‘jaundiced foal’ or ‘haemolytic foal’, occurs when the foal receives colostrum from the mare that contains antibodies against its own red blood cells. These antibodies then destroy the foal’s red blood cells, resulting in anaemia and an increase in bilirubin (a product of red blood cell break down). This, in turn, causes a jaundiced or yellow appearance of the gums.

The mare develops antibodies by being exposed to the blood of a previous foal (such as during foaling or with a placentitis) or having a previous blood transfusion. A foal is then affected if it has inherited the same blood type from the stallion that the mare has produced antibodies against. There are many different equine blood types but, unfortunately, the two most common types are the ones often involved in NI.

Depending on the severity of the destruction of the red blood cells (haemolysis), symptoms can develop within six hours or until around seven days of age; the longer the onset period, the less severe the haemolysis. Signs of NI range from an increased respiratory rate and jaundiced (yellow) mucous membranes, to inability to stand, weakness and seizures.

The treatment for this condition varies from oxygen therapy and/or a blood transfusion to just careful monitoring, with some severely affected foals dying despite intensive intervention. Preventative measures can be taken with mares that are known producers of foals with NI by not allowing their newborn any access to nurse for 48 hours. Arrangements should be made for the foal to receive its colostrum and milk from another source, while the mare is milked out for 48 hours and her milk and colostrum discarded. After this period of time, the foal can then nurse from its dam.

Umbilical Problems
The umbilicus, or navel, needs to be closely monitored for the first few weeks of life. Shortly after birth, it should be moist but if it seems to be bleeding excessively, this requires veterinary attention. It can also become infected, in which case it may be swollen and tender to touch, with or without pus present. Sometimes, an infection can be located in the internal part of the umbilicus, so there are no obvious external signs and an ultrasound examination may be required. The umbilicus may also leak urine (patent urachus).

The umbilicus should be carefully disinfected shortly after it breaks and twice daily for the first 2-3 days after birth. Dilute disinfectants such as 2.5% iodine are recommended, as anything stronger may be caustic and lead to tissue damage. The solution is best applied with a small spray bottle, spraying the umbilicus but avoiding the surrounding skin.

The majority of foals with a patent urachus or infected umbilicus will respond to antibiotic therapy and being kept in a clean dry yard or small paddock. Previously surgery was recommended, however now it has been found that the majority of these conditions resolve with medical treatment alone.

Entropion
Entropion can be present at birth or occur after birth, and is usually associated with prematurity, dehydration, or generalised muscle weakness. It occurs when the eyelid, most commonly the lower one, rolls in. If left untreated, the hair from the eyelid rubs on the cornea and this irritation leads to the formation of a corneal ulcer - which can be a very serious condition resulting in loss of the eye.
If an entropion is seen, the eyelid can be manually rolled out then examined by a veterinarian to determine if an ulcer has formed. The eyelid may also need to be sutured to stop it rolling in until the dehydration or muscle tone improves. Corneas are less sensitive in foals than in mature horses, thus ulceration can be present without evidence of pain and special fluorescein staining is needed to highlight the damaged area. Treatment may involve topical broad-spectrum antibiotic therapy, though severe deep ulcers may require surgical treatment.

Treatment of the critically-ill newborn is time and labour intensive but, when problems are detected at an early stage and if aggressive veterinary treatment is applied, the chances of achieving the successful outcome of a live, healthy foal are considerably higher.

Supplied by Equine Veterinarians Australia (EVA).
For more information go to the web site: www.eva.org.au

Dr Jane Axon BVSC(Hons)MACVSc DACVIM
Jane currently practices at Scone Veterinary Hospital in NSW, where she is veterinary director of Clovelly Intensive Care Unit. Over 400 foals a year are hospitalised and treated at the facility, which is the centre of the largest equine breeding region in the southern hemisphere.

Scone Veterinary Hospital
Contact - www.sconevet.com.au