Hypoplastic left ventricular syndrome in a foal

A necropsy diagnosis of hypoplastic left ventricular syndrome was made in a day-old foal. The cardiac abnormalities included mitral and aortic valve atresia, patent ductus arteriosus, and a secundum atrial septal defect. The left ventricle was hypoplastic and nonfunctional. The brief survival of the foal was a consequence of left-to-right shunting through the atrial septal defect and right-to-left shunting through the patent ductus. The information is presented to demonstrate the existence of the syndrome as a congenital defect in the horse and to clarify the necropsy findings for the practitioner to diagnose if seen.     

Atrial septal defect of the persistent ostium primum type with hypoplastic right ventricle in a Welsh pony foal.

Valvular competency of the foramen ovale (patent foramen ovale) is regarded as a common finding in the neonatal foal and usually occurs in isolation. True atrial septal defects appear to be uncommon and are usually associated with other congenital cardiac lesions. The present report describes a case of atrial septal defect type 1 (persistent ostium primum) complicated by hypoplastic right ventricle, and tricuspid dysplasia, in a Welsh Mountain pony foal, and discusses the embryogenesis of the abnormality. A critical review of the literature suggests that atrial septal defects may occur more frequently than they are reported, and that on occasion they may be described erroneously as patent foramen ovale. The clinical significance of uncomplicated discontinuity of the atrial septum is slight, depending upon the size and location of the defect. Complicated atrial septal defects vary in clinical significance according to the nature of the associated defects.     

Tricuspid atresia in a foal

An Arabian crossbred foal was examined because of a suspected congenital cardiac anomaly. There was a grade V/V crescendo-decresendo holosystolic murmur and thrill in the left 4th intercostal space. The foal was slightly cyanotic and polycythemic. Electrocardiography suggested left ventricular hypertrophy. Angiography and cardiac and vascular pressure recordings led to a diagnosis of pulmonic stenosis. The foal died after cardiac bypass and corrective surgery. Postmortem examination revealed an enlarged right atrium, atresia of the tricuspid orifice, a large, fenestrated patent foramen ovale, eccentric left ventricular hypertrophy, and a large interventricular septal defect. The right ventricle had a small lumen and a relatively thick wall. There was valvular and supravalvular pulmonic stenosis, with poststenotic dilatation of the pulmonary artery. A single coronary artery originated from the anterior sinus of the aorta.     

AGENESIS OF THE DISTAL PHALANX IN A MULE

Agenesis of the distal phalanx of a mule foal is documented. The condition was identified when the foal was 14 days old and supported by follow-up radiographs obtained at four months of age.     

ISOLATION OF AN ADENOVIRUS FROM AN ARAB FOAL WITH A COMBINED IMMUNODEFICIENCY DISEASE

Some details of the clinical and postmortem findings of an Arab foal that died as a consequence of adenoviral pneumonia superimposed on a combined immunodeficiency disease are provided. The foal was the 17th in a series of similar deaths that occurred on a farm since 1959. An adenovirus, which by haemagglutination inhibition and serum neutralisation tests was antigenically similar to 2 other equine adenoviruses isolated in Australia, was isolated from a nasal swab taken from the foal when it was 23 days of age.     

RADIOGRAPHIC DIAGNOSIS OF GASTROINTESTINAL DISORDERS IN THE FOAL

Abdominal discomfort in the foal presents a diagnostic challenge, because the small size of the foal precludes rectal palpation. Standing lateral horizontal beam abdominal radiographs using conventional techniques were evaluated as a diagnostic aid to identify the presence and location of gastrointestinal disorders in foals presented with colic. Forty foals were radiographed prior to surgery (20 foals), necropsy (7 foals), or clinical diagnosis (13 foals). Clinical, surgical, or necropsy findings were then correlated to radiographic findings. Gastrointestinal disease was accurately identified on radiographs as the source of colic in 25 of 26 foals that had surgical or postmortem confirmation. The site of disease, whether gastric, small intestinal, large intestinal, or a combination, was accurately determined from radiographs. Standing lateral abdominal radiographs were determined to be a valuable diagnostic aid in the foal presented with colic.     

Interruption of aortic arch in two foals

Two foals with a history of normalcy at birth developed a lack of exercise tolerance and weakness in the first few days of life. Weakness, inability to rise, and reluctance to suckle were common complaints. Physical examination of both foals revealed a cardiovascular abnormality, with a loud systolic murmur audible over both thoracic walls. Additional diagnostic techniques were blood gas analysis, radiography, cardiovascular catheterization, and necropsy. Necropsy findings were ventricular septal defect, atrial septal defect, patent ductus arteriosus, and congenital absence of the aortic arch. Additionally, 1 foal had anomalous drainage of the cranial vena cava into the left atrium.     

Maternal behavior

Parturition in mares is rapid and is followed by a brief period of sensitivity to imprinting on a foal. There is large individual variation in normal maternal style, but normal mothers actively defend their foal, remain near the foal when it is sleeping, tolerate or assist nursing, and do not injure their own foal. Disturbance of a mare and foal during the early imprinting period can predispose a mare to rejection of her foal; therefore, it should be avoided. There are a variety of forms of foal rejection and numerous etiologies. Therefore, each case should be evaluated individually.     

Hepaticojejunostomy for Treatment of Common Hepatic Duct Obstructions Associated with Duodenal Stenosis in Two Foals

Two female Standardbred foals 2 and 3 months of age were presented with signs of gastroduodenal obstruction that was confirmed with contrast radiography and exploratory surgery. Ventral midline celiotomy was performed, showing stenosis of the duodenum proximal and distal to the hepatopancreatic ampulla. The common hepatic duct, the pancreatic duct, and the sigmoid section of the duodenum proximal to the stenosis were greatly dilated. To bypass the intestinal obstruction, a side-to-side duodenojejunostomy was performed. Obstruction of the common hepatic duct was relieved by side-to-side hepaticojejunostomy. In addition, jejunojejunostomy was performed distal to the other anastomoses. Both foals recovered. On admission, the foals' total bilirubin, aspartate aminotransferase, and gamma glutamyl transferase levels were greatly elevated. During the subsequent 6 to 8 months, they returned to normal. Six months after the first surgery, one foal was readmitted with an acute abdominal crisis. At surgery, there was greater than 360 degrees clockwise rotation of the mesenteric root involving most of the jejunum. At necropsy, the previously created stomas were patent. The liver and bile duct were grossly and histologically normal. The second foal continues to progress normally 12 months after surgery.     

An unusual cause of colic in a neonatal foal

A case of a neonatal foal with acute colic and respiratory distress is described. The foal presented with signs of acute colic and was treated medically. The foal did not respond to treatment and 2 h after admission the foal began to demonstrate signs of respiratory distress. Thoracic and abdominal radiographs were obtained and a diagnosis of a diaphragmatic hernia was made. Surgical repair of the hernia was recommended but the owner declined and the foal was subjected to euthanasia. Post mortem findings confirmed the diagnosis and revealed that the defect was of congenital origin. Congenital diaphragmatic hernia is an unusual cause of colic in a neonatal foal.     

Use of Renal Replacement Therapy in a Neonatal Foal with Postresuscitation Acute Renal Failure

A newborn foal was presented because it was unresponsive and in cardiopulmonary arrest. Aggressive cardiopulmonary cerebral resuscitation was administered to the foal, which revived the foal; however, acute renal failure developed. Fluid retention and azotemia occurred although the foal was alert and able to suckle. A 6‐hour renal replacement therapy session using hemodiafiltration and a continuous renal replacement therapy machine was administered to the foal at 3 days of age which lowered the foal's azotemia and facilitated removal of some of the excess body fluid. Despite therapy, the foal developed pulmonary edema and was euthanized. Although the foal in this case did not survive, this report highlights the possibility of developing postresuscitation complications such as acute renal failure and describes the use of renal replacement therapy using hemodiafiltration as a viable option in neonatal foals with acute kidney injury.     

Aggression to a foal after 4 months of nursing

A 4-month-old male Arabian foal was examined because of a kicking trauma to the right frontal region. The foal had been kicked by its dam when it was seeking the udder the previous day. Radiographic inspection of head and neck showed no defect or bone fracture. Treatment consisting of intravenous administration of hypertonic solution, dexamethasone, and furosemide improved the clinical signs temporarily; however, second head trauma due to falling of the standing foal resulted in deterioration of clinical condition and finally death. At necropsy, epidural, subdural, and subarachnoid hemorrhages, a hematoma at cerebrocerebellar fissure and cerebellar herniation were observed. Continuous assessment of foal rejection-related signs in susceptible mares should be considered until foal weaning.     

ECHOCARDIOGRAPHIC EVIDENCE OF AN AORTICO-PULMONARY SEPTAL DEFECT IN A 4-DAY-OLD THOROUGHBRED FOAL

We describe the echocardiographic findings in a 4-day-old thoroughbred foal with an aortico-pulmonary septal defect. The foal had labored breathing, cyanotic mucous membranes and a continuous grade 5/6 heart murmur with point of maximal intensity over the base of the heart on the right side. Echocardiographically, there was a large communication between the aorta and the pulmonary artery just dorsal to the base of the heart. The cardiac anomaly seen during the echocardiographic exam was confirmed at necropsy where a large communication between the two great vessels was observed. These findings correlate with previous studies in humans, dogs, and cats. The possible failure in the embryologic development that led to this unusual cardiac anomaly is discussed.     

COMPUTED TOMOGRAPHIC EVALUATION OF HEAD TRAUMA IN A FOAL

This case report describes computed tomographic findings of a three-month-old, 180 kg female Arabian foal that had suffered head trauma. Computed tomography proved valuable in antemortem diagnosis of skull base fracture and extradural hematoma, which were confirmed by postmortem examination.     

A XERORADIOGRAPHIC STUDY OF OSTEOCHONDROSIS IN THE METACARPOPHALANGEAL REGION OF TWO FOALS

Using xeroradiographic techniques, both metacarpophalangeal regions of six quarter horse foals were radiographed at 1 day of age and at 2-week intervals until they were 6 weeks old, and then at 4-week intervals until they were 12 months old. Lateromedial and dorsopalmar xeroradiographs of each metacarpophalangeal region were made per examination; dorsomedial-palmarolateral projections of the left metacarpophalangeal joint of foal 6 were also made. The foals were weighed and measured at the withers immediately prior to each examination. Representative xeroradiographs were selected to demonstrate progression of the osteochondrosis (OCH) lesions in two of these foals. Radiographic evidence of osteochondrosis in the metacarpophalangeal region was first detected at 10 weeks and followed through 12 months of age. In one foal the lesions were bilaterally symmetric and involved the dorsoproximal aspect of the sagittal ridge of metacarpal 3; in the other, the left medial proximal sesamoid bone was affected. One of the sagittal ridge lesions progressed to osteochondritis dissecans by 26 weeks; the other sagittal ridge lesion and that of the sesamoid bone healed spontaneously, but residual radiographic evidence of the disease persisted throughout the study in both foals.     

Transfer of tumour necrosis factor-α via colostrum to foals

This study aimed to determine whether TNF-α is transferred to equine neonates via colostrum and the relationship between TNF-α and IgG concentrations in the equine neonate. Colostrum, presuckle and postsuckle foal serum samples were collected from healthy mares and their foals. Equine TNF-α ELISA and IgG SRID kits were used to determine the concentrations of TNF-α and IgG, respectively. Statistical analysis was performed using the Spearman rank correlation. TNF-α concentrations in all presuckle foal serum were below the limit of detection in 15/16 foals and increased in postsuckle foal serum to a mean concentration of 7.7 x 10(4) pg/ml. TNF-α concentrations in postsuckle foal serum and colostrum showed significant correlation (rho=0.668; P=0.005). However, TNF-α and IgG concentrations in colostrum or postsuckle foal serum did not correlate (rho<-0.016; P>0.05). Ratios of TNF-α/IgG in colostrum or postsuckle foal serum showed significant correlation (rho=0.750; P=0.0008). These results indicate that TNF-α is transferred to the foal via colostrum absorption and may play a role in early immunity.     

Double-outlet right ventricle in an Angus calf

Double-outlet right ventricle (DORV) is a conotruncal malformation where both great arteries arise from the right ventricle. Anatomic variations of DORV are classified according to the position of the great arteries in relation to each other, the relationship between a ventricular septal defect (VSD) and the great arteries, and the presence and degree of pulmonary stenosis. The prevalence of congenital cardiac defects in bovine fetuses has been reported at approximately 0.7 %, with VSDs representing the most common congenital cardiac defect. DORV has been described in veterinary literature in few cats and dogs, a foal, and 2 calves with variable clinical and pathologic documentation. In this report, we describe the angiographic, echocardiographic, and postmortem examination findings in a calf with a DORV with concurrent pulmonary stenosis, subaortic VSD, patent ductus arteriosus (PDA), aberrant left subclavian artery, and a tracheal malformation.     

Placental teratocarcinoma in a mare with possible metastasis to the foal.

A teratocarcinoma was diagnosed in the amnion of a 5-year-old Arabian mare that delivered a healthy, full-term foal. The foal died at 2.5 months of age as a result of metastasis of an undifferentiated component of the mass. This case is unique because it is the first reported case of placental teratocarcinoma in animals and the malignant component apparently metastasized to the foal resulting in its death.     

Molecular and cytogenetic paternity testing of a male offspring of a hinny

An alleged male foal of a female mule, whose sire and grandparents were unknown, was identified for its pedigree. Parentage testing was conducted by comparing polymorphism of 12 microsatellite DNA sites and mitochondrial D‐loop sequences of the male foal and the female mule. Both the sequence analysis of species‐specific DNA fragments and a cytogenetic analysis were performed to identify the species of the foal and its parents. The results showed that the alleged female mule is actually a hinny, and the male foal, which possesses 62 chromosomes, qualifies as an offspring of the female hinny and a jack donkey.     

Postoperative Myositis in a Neonatal Foal: A Case Report

A foal with azotemia, acidemia, and electrolyte abnormalities was diagnosed with uroperitoneum. The foal was anesthetized with isoflurane, and throughout the 4 hours of anesthesia and abdominal surgery, its mean arterial pressure ranged between 45 and 65 mm Hg. The foal developed a myopathy postoperatively and died 24 hours after surgery.