Dr* Robert Hillman Cares for a Newborn with Assistance from Judy Chapman
Total Page：16
File Type：pdf, Size：1020Kb
Dr* Robert Hillman cares for a newborn with assistance from Judy Chapman. DO YOU HAVE A 'PREEMIE1? The perinatal period for the equine has been defined as the period from Day 300 of gestation, generally considered to be the lowest By Pamela Livesay-Wilkins '86 limit of viability, to 96 hours post-partum, "ith Special Thanks to Dr. Diane Craig when the foal is considered to have reached a steady state of body functions, recovering from the stresses of birth. Events in the fetus and in the mother need to be closely coordinated so There are times when the mother and the that the mother will give birth to a full-term, ^ tus are prepared for birth at different stages mature foal that is capable of survival outside ?f gestation. When it happens that the mother the uterus. However, there are a variety of ls ready first, the foal may be born premature. conditions that can occur and indicate that the Approximately 1% of all Thoroughbreds are mother and fetus were not equally prepared for “orn prematurely, and the incidence approaches birth. Most forms of prematurity have a this value in most other breeds, so it isn't common cause with abortion and the distinction surprising that most active horse breeders have between them is rather arbitrary, based t° deal with the problem of a premature foal at primarily on the prospect for fetal survival and some point. In the last decade the value of gestational age of the fetus. Chronic placental horses, particularly Thoroughbreds, has insufficiency due to twinning, body pregnancy Increased tremendously, reflected by an (pregnancy located in the body of the uterus increased interest on the part of both the rather than in one of the uterine horns), veterinarian and the client in neonatal critical umbilical cord abnormalities, hydrops of the care and management techniques. While the allantois (excessive accumulation of fluid in the field of neonatal equine medicine is still fetal membranes), or fungal or bacterial considered to be, itself, in infancy, progress has infections can deprive the fetus of the oxygen been made in the areas of diagnosis and it requires and precipitate a premature birth. Management of these foals. EQUINE B o u n d s Premature placental separation can acutely closely by trained personnel, as neonates are deprive the fetus of oxygen, again resulting in a quite capable of changing their condition very premature birth. Other causes of prematurity rapidly, with only subtle clues indicating that a include fetal deformity, maternal malnutrition, change for the worse is about to occur! induction of parturition and the Equine Herpes Type I virus (the rhino virus). The first step in managing the premature foal is to determine if there is a need for Diagnosing prematurity in a foal is not a immediate intervention. Apnea, or lack of difficult undertaking if the foal is obviously breathing effort, can occur and there are steps premature. The foal will be small and its coat that can be taken to aid the foal while help is will be short and silky. Its fetlocks will be being summoned. If a foal is not breathing, dropped (hyper-extended) and it will be slow to mouth-to-nose resuscitation can be performed. stand and suck. If it is very premature it may Any obstruction of the airway, such as amnionic have decreased or absent suck and righting remnants, should be removed. The foal's neck reflexes. If a Thoroughbred foal is born at less is extended, the down nostril is held closed and than 320 days of gestation, prematurity can be a breath large enough to cause the chest to diagnosed even in the absence of other signs of visibly rise and fall is delivered to the up nostril prematurity. If the foal is not obviously at a rate of 20 to 30 times per minute. The premature it may or may not show any or all of foal may also be stimulated to breathe by the above signs. In these cases, a veterinarian slapping its chest several times sharply with an , can make the diagnosis based on such open palm. Artificial ventilation may also be parameters as venous blood pH, total red blood provided by endotracheal intubation and use of cell count, white blood cell differential count a ventilator or a specialized breathing bag that and the neutrophil to lymphocyte ratio. In delivers oxygenated air if a veterinarian is cases that are still in doubt, further tests such present. All ventilation supports should be as measurement of circulating plasma cortisol suspended for a short time periodically to levels and performing an ACTH challenge test determine if the foal is making an effort to will help clarify things. The primary breathe on its own. Evaluation of differential diagnosis when considering cardiovascular status and administration of prematurity is infection of the foal, either in appropriate support for this system should only utero or following birth. The septicemic foal be done by a veterinarian and one should be will eventually have an elevated rectal summoned for any critically ill or non- temperature and cells called band cells will be responsive foal. seen on the differential white blood cell count. Infected foals may present with a diminishing Once the premature foal is over any suck reflex and will develop some localizing immediate crisis, the decision should be made sign of infection such as pneumonia, diarrhea, to either send the foal to a neonatal critical lameness or peritonitis. It should be kept in care unit or to nurse it at home. Distance, mind, however, that premature foals have a availability and financial considerations may diminished ability to fend off infection and may preclude sending the foal to a critical care unit, become septic. It is possible that the so many of these foals are nursed at home. premature foal may be born alive and found This can be successful, but it should be dead if the birth was unattended. In these remembered that this is a time-consuming cases the diagnosis can be made at autopsy. arduous route to take. Stalls are dirty and can J serve as a source of contamination to the foal- Whether you attend the birth yourself or Additionally, the lighting is generally poor and the birth is attended by a veterinarian, it the mother may be uncooperative. Although becomes important to recognize the premature for bonding purposes it may be desirable for the condition of a foal as early as possible. It is foal to stay with its mother, these other critical that the abnormal neonate be observed considerations generally require that the foal 1__ __________j________ _ _______ _______ _ f ft J EQUINE B o u n d s environment with clean, warm, dry, soft hour. However the foal is fed, its body weight bedding and a thermally neutral temperature. should be monitored daily and if it is seen to Heat sources can be in the form of heating pads decrease the method of feeding should be 0r lamps and a twin sized water-bed with a reevaluated. beater is ideal for maintaining a critically ill Infection is the most common downfall of foal. the premature foal and failure of passive Normally hydrated critically ill foals transfer due to insufficient colostrum ingestion Produce large amounts of very dilute urine, so is commonly implicated. The immunoglobulin Provision should be made for mopping this up level of every foal should be determined and and keeping the foal clean and dry. Also, foals treatment with either colostrum orally (if the breathe best, and receive more oxygen if they foal is less than 18 hours old) or administration are in sternal recumbance (resting on their of plasma intravenously should be done if the sternum) rather than on their sides. Large immunoglobulin level is less than 800 mg/dl. Wedge shaped pieces of sturdy foam can be used Any foal that is presenting signs of possible to support a foal in this position and the foal infection should be placed on a broad-spectrum should be turned a minimum of every two hours bacteriocidal antibiotic combination such as both to aid its breathing efforts and to prevent penicillin and an aminoglycoside immediately. bedsores. A veterinarian should be consulted when decisions concerning route, dosage and choice Some provision will also need to be made of antibiotic are made, as the foal's renal and f°r feeding the foal. The intestinal tract of liver function, hydration status, age and Many premature foals will be insufficiently maturity will affect these decisions, as will the developed to allow feeding with milk. In these type of bacteria involved. The veterinarian cases, feeding of glucose and electrolyte may also want to consider the foal's adrenal solutions may be considered or parenteral status, as this affects immunocompetency, and feeding (feeding through a vein) may be may suggest treatment for adrenal required. Parenteral feeding should only be insufficiency. Nursing care, of course, becomes done with the direct supervision of a paramount in preventing infection. veterinarian. Premature foals are now surviving in Mare's milk is, of course, the fluid of greater numbers than ever before, and the choice for feeding the premature foal and it advent of neonatal critical care units and May be bottle fed if the foal has a suck reflex. research groups are increasing the knowledge If the foal is very weak or unwilling to suck, and ability of veterinarians in the field to treat then milk may be administered through a this condition. Not every abnormal neonatal nasogastric tube. Some common complications foal can be saved, but many are going on to °f tube feeding, such as gas distention, colic, lead normal and productive lives.