"Foals" encompasses a stage in the lifecycle of equines with distinct physiological and developmental characteristics. Foals are young horses, typically under one year of age, undergoing rapid growth and development. They require specific nutritional, health, and management practices to support their transition to adulthood. This page compiles peer-reviewed research studies and scholarly articles that explore the growth, development, health challenges, and management practices associated with foals and horses, providing insights into their care and welfare across different life stages.
Fowden AL, Silver M, Ellis L, Ousey J, Rossdale PD.The factors influencing beta cell function in the foetal and neonatal foal have been investigated in chronically catheterised foetal foals and in newborn foals delivered either spontaneously at term or by induction at different gestational ages. Insulin was detected in the foetal plasma from as early as 150 days of gestation (term = 340 days) and during the last third of gestation the foetal beta cells responded to exogenous administration of glucose and arginine and to endogenous variations in the glucose level. Insulin secretion by the foetal beta cells was depressed by anaesthesia and surge...
Clemmons RM, Dorsey-Lee MR, Gorman NT, Sturtevant FC.Whole blood platelet counts, coagulation profiles and in vitro platelet function tests were monitored in newborn foals during the first week of life. Platelet counts, mean platelet volumes and thrombin-induced malondialdehyde production were not different from adult mares. Prothrombin and partial thromboplastin times were slightly, but not significantly, longer for neonatal blood samples than for mare samples. Platelet aggregation responses to serotonin, arachidonic acid or adrenaline did not change during the study. On the other hand, adenosine diphosphate-induced aggregation and collagen-ind...
Broughton Pipkin F, Ousey JC, Wallace CP, Rossdale PD.Plasma renin substrate concentration was measured in 18, four-day-old pony foals after the administration of the natriuretic agent frusemide. Thirteen foals had been delivered spontaneously; labour had been induced in the remaining five mares. Plasma aldosterone concentration was measured in 12 of the spontaneously delivered foals. Renin substrate concentration had risen sharply within 15 mins (P less than 0.005) and peaked at 1 h. The response was consistently greater in the induced foals. Serum sodium concentration fell rapidly in the induced foals (P less than 0.002 by 60 mins) but was bett...
Silver M.THERE is no shortage of anatomical information on the equine foetus and its placenta, from the early work of Ruini in the 16th century to the recent studies of Steven and colleagues (Steven 1982); by contrast, knowledge of the physiology of the foal in utero is sparse. In other domestic animals there have been considerable ads ances in foetal and neonatal physiology and endocrinology in recent years due mainly to the develop-ment of the chronically catheterised foetal preparation in which sequential observations can he made in the conscious animal (Silver 1981). Some information about the deve...
Stewart JH, Rose RJ, Barko AM.Respiratory measurements and blood-gas and acid-base values are reported in nine term induced foals. Measurements were performed at 2, 15, 30 and 60 mins, 4, 12, 24 and 48 h, and four and seven days after birth. Minute respiratory volume was significantly lower at birth than values from 12 h old. Tidal volume peaked at 60 mins old, while respiration rate decreased significantly at 15 mins after birth. Oxygen consumption was high at birth and decreased to its lowest values at 24 and 48 h. The respiratory exchange ratio and ventilatory equivalent showed few significant changes to seven days, as ...
Webb AI, Coons TJ, Koterba AM, Kosch PC.New developments in therapy for foals in respiratory distress are discussed. Therapy is based on preservation of the foal's life by maintenance of a patent airway, resuscitation with fluids and warmth, provision of humidified oxygen to raise the fractional concentration of inspired oxygen sufficient to avoid hypoxia and provision of ventilatory support when hypercapnia becomes critical. Ventilatory support described includes assisted and controlled ventilation, positive end expiratory pressure, continuous positive airway pressure and intermittent mandatory ventilation. The aims of these techni...
Rossdale PD, Ousey JC, Dudan FE, Leadon DP, Cash RS, Reddy R, Silver M, Fowden A, Broughton Pipkin F, Jeffcott LB.This paper describes the general management of mares and foals during the perinatal period and the methodology used in a collaborative research project on equine prematurity. Sixteen mares with dated pregnancies delivered 45 foals over three breeding seasons (1981 to 1983). In the majority, parturition was induced with oxytocin and/or fluprostenol; the remainder were allowed to foal spontaneously. Pre-colostral milk analysis provided a means of assessing the pre-foaling status of the mare. All were observed and monitored before, during and after parturition and the sampling protocol for both m...
Brown MP, Gronwall R, Kroll WR, Beal C.Five foals from two to three days old were given a single oral dose of ampicillin trihydrate (20 mg/kg bodyweight [bwt]). Serum ampicillin concentrations were measured serially over a 24 h period. The study was repeated in the same foals at 16 to 21 days old. The mean peak serum ampicillin concentration at two to three days old was 5.0 micrograms/ml at 1 h after treatment; the mean peak serum concentration at 16 to 21 days old was 2.7 micrograms/ml at 2 h. The concentrations steadily declined and ampicillin was not detected in the serum from any of the foals by 24 h. Serum clearance averaged 1...
Irvine CH.Hypothyroidism in the foal occurs as two entities because of the separate actions of thyroid hormones in regulation of metabolic rate and in cell differentiation. The hypometabolic state which results in inadequate thermogenesis and lethargy, occurs concurrently with a period when thyroid hormone secretion is inadequate. Also the severity of the concurrent symptoms is related to the degree of hormone inadequacy as measured by plasma concentrations of free T4 and T3. By contrast, the developmental lesions caused by hypothyroidism are often observed during periods when plasma thyroid hormone con...
Baggot JD, Short CR.Differences between neonatal and adult animals in their response to drugs can usually be attributed to altered disposition (ie, distribution, metabolism and excretion) processes during the neonatal period. These alterations affect the plasma concentrations as well as the concentrations of drug attained at the receptor site. Some characteristics of the neonatal period include greater absorption from the gastrointestinal tract, lower extent of plasma protein binding, increased apparent volume of distribution of drugs that distribute in extracellular fluid or total body water, increased permeabil...
Stewart DR, Kindahl H, Stabenfeldt GH, Hughes JP.Changes in plasma 15-keto-13, 14-dihydro-prostaglandin F2 alpha were monitored at frequent intervals before, during and after spontaneous deliveries (three mares) and foalings induced by oxytocin (eight mares). No evidence of increased concentrations of the prostaglandin metabolite was observed in the final 10 days of gestation. In spontaneously delivering mares, there was a marked increase from 3 ng/ml at -125 mins to 18 ng/ml at -65 mins to the highest observed value of 182 ng/ml at 20 mins pre-partum. Following delivery, concentrations declined rapidly to around 0.2 ng/ml. Further release o...
Kosch PC, Koterba AM, Coons TJ, Webb AI.Developments in evaluation of newborn foals with respiratory distress are discussed. Major causes of respiratory distress are outlined and discussed in terms of the similar respiratory signs exhibited by foals with this clinical syndrome. History, physical examination, clinical pathology, chest radiography and blood gas analyses are discussed as important elements of the evaluation of the condition of these foals. Foals with respiratory disease are grouped into three major categories on the basis of clinical signs and arterial blood gas profiles. The evaluation of foals with respiratory distre...
Stewart JH, Rose RJ, Barko AM.Simultaneous echocardiograms, phonocardiograms and electrocardiograms were performed on 16 foals at the following times after birth: 15 mins, 60 mins, 2, 4, 12, 24, 48 h, four, seven, 14 days and four, eight and 12 weeks. Positive correlations were found between both age and body weight and the following measurements: left ventricular end-diastolic dimension, right ventricular end-diastolic dimension, left atrial dimension and aortic root dimension, posterior left ventricular wall thickness and interventricular septal thickness. Heart rate was negatively correlated with left ventricular electr...
Lombard CW, Evans M, Martin L, Tehrani J.Twelve newborn pony foals underwent cardiovascular examinations (auscultation, arterial blood pressure measurements, electrocardiograms and M-mode echocardiograms) on their first day of life and then on Days 7, 14, 21, 30, 60 and 90. An age dependent, statistically significant, rapid increase of the arterial blood pressure in the first month was documented together with a slower decrease of the resting heart rate after two and three months of life. Innocent soft systolic murmurs were audible over the left heart base in a large number of the foals. The electrocardiograms showed age dependent in...
Palmer AC, Leadon DP, Rossdale PD, Jeffcott LB.A neuropathological examination was carried out on the brains of 58 foals. Forty-two were pony foals induced at various periods of gestation from 200 days onwards. Two were pre-viable pony foals delivered by caesarean section and 14 were Thoroughbred foals (one set of twins, two stillborn, five premature, two dysmature, two convulsive and one induced). The only significant pathological change involved intracranial haemorrhage. Subarachnoid haemorrhage occurred in all of 10 pony foals induced before 301 days of gestation and in two pony foals born by caesarean section at 270 and 280 days gestat...
Koterba AM, Brewer BD, Tarplee FA.In an effort to identify improved methods for diagnosis of infection in the neonatal foal, clinical records from 38 septicaemic foals of less than one week of age were examined for trends in history, physical examination and clinicopathological findings. The survival rate of septicaemic foals, 26 per cent, was markedly less than the rate for all other foal admissions. Blood cultures were valuable in diagnosis and treatment of septicaemia and identified a preponderance of Gram-negative infection. Zinc sulphate turbidity test results were abnormally low in all septicaemic foals tested. The clini...
Harvey JW, Asquith RL, McNulty PK, Kivipelto J, Bauer JE.Packed cell volume, haemoglobin concentration, erythrocyte counts, erythrocyte indices, serum iron, iron binding capacities, total and differential leucocyte counts, platelet counts, total plasma protein, fibrinogen, haptoglobin and icterus index values were determined at 14 different ages in eight Thoroughbred and 14 Quarterhorse foals during the first year of life. Absolute neutrophil numbers in blood decreased and lymphocyte numbers increased during the first months. Absolute eosinophil numbers tended to increase until three months old. Haemoglobin concentration and packed cell volume decre...
Adams R, Mayhew IG.Behaviour and response to neurological testing of apparently healthy newborn foals differed significantly from the adult in several ways. Foals responded to external stimulation with exaggerated movements although they tended to sink into a relaxed state when restrained. They had a more angular head position and assumed a base wide stance. The menace reflex developed during the first two weeks post partum. In general, the foals' gait was choppy or dysmetric. In lateral recumbency the foals had increased extensor tone, hyperreflexive tendon reflexes, crossed extensor reflexes as well as recumbe...
Silver M, Ousey JC, Dudan FE, Fowden AL, Knox J, Cash RS, Rossdale PD.Adrenocortical and medullary function was investigated during the immediate post natal period in premature and full term foals. High plasma cortisol concentrations were characteristic of the term foals in the first 2 h after birth and these were accompanied by significant arteriovenous differences in plasma cortisol across the umbilical circulation at birth, indicating enhanced adrenal activity before delivery. No such arteriovenous differences were detected in the premature group and post natal changes in plasma cortisol were minimal. The apparent inability of the premature foal adrenal to se...
Leadon DP, Jeffcott LB, Rossdale PD.Total calcium, total protein, albumin and globulin content were determined in 49 samples of mammary secretions from 37 crossbred and Thoroughbred mares. The mares were divided into three categories: Group 1--post partum samples from spontaneous full term Thoroughbred deliveries (n = 20); Group 2--pre- and post partum samples from spontaneous full term Thoroughbred deliveries (n = 6); Group 3--pre- and post partum samples from induced premature deliveries in crossbred mares (n = 11). Calcium concentrations of the mammary secretions proved useful in predicting full term and also in assessment of...
Spehar AM, Hill MR, Mayhew IG, Hendeles L.Pharmacokinetic characteristics of the anticonvulsant phenobarbital were studied in seven pony and two Thoroughbred foals aged between four and 10 days. A single, 20 mg/kg bodyweight (bwt) dose of phenobarbital was given intravenously over 25 mins and the serum concentrations of the drug were measured using an EMIT AED assay (coefficient of variation 1.37 per cent at 30 micrograms/ml, n = 7). Phenobarbital elimination was found to follow first order kinetics. The mean (+/- sd) peak phenobarbital serum concentration was 18.6 +/- 2.1 micrograms/ml at 1 h after initiation of infusion with a mean ...
Ousey JC, Dudan FE, Rossdale PD, Silver M.The effectiveness of the prostaglandin F analogue fluprostenol in inducing labour in the mare was examined by giving sequential injections over the last 50 days of gestation. The behavioural and endocrine changes elicited by the drug in pregnant and non-pregnant animals and in foals were also studied. Fluprostenol (250 or 500 micrograms intramuscularly) failed to induce labour before 320 days gestation; thereafter its effect was capricious. Twelve mares foaled 1 to 36 h after the last test; eight delivered normal, viable, apparently 'term' foals and four produced stillborn/premature animals. E...
Manneveau GB, Robert MP, Tessier C, Bizon-Mercier C.This report describes a rare case of gastric impaction caused by a trichophytobezoar in a foal. This case highlights the difficulty in diagnosing this condition and reports surgical removal via a gastrotomy after failure of medical treatment. Ablation chirurgicale d’un trichophytobézoar gastrique chez un poulain. Ce rapport décrit un rare cas d’obstruction gastrique causé par un trichophytobézoar chez un poulain. Ce cas souligne la difficulté à diagnostiquer cette affection et fait rapport sur l’ablation chirurgicale lors d’une gastrotomie après l’échec du traitement médical...
Leadon DP, Rossdale PD, Jeffcott LB, Allen WR.Various regimens of prostaglandins, alone or followed by oxytocin, were given to induce parturition in mares during the pre-viable and premature periods of gestation and in near-term mares. The most successful method of induction was found to be 2 i.m. injections of 500 micrograms fluprostenol (Equimate: I.C.I.) at a 2-h interval followed (if necessary) by 10-20 i.u. oxytocin injected i.v. in 5 i.u. serial increments every 15-20 min. Peak concentrations of the prostaglandin metabolite (PGFM) in response to the inducing agents were shown to be associated with delivery at, but not before, 320 da...
Sonmez K, Gurel A, Takai S.The aim of the present study was to develop an immunocytochemical procedure for the early detection and demonstration of Rhodococcus equi in smears of tracheal aspirates taken from live foals in field conditions. Tracheal wash samples were collected from thoroughbred foals, aged 1-5 months and located in studs around Bursa and Istanbul, Turkey. Some foals were suspected of having R. equi infection on the basis of clinical examination (n=56) and others were unaffected control animals (n=54). Serum samples were also collected from each foal for testing for the presence of R. equi-specific antibo...
Stammers JP, Leadon DP, Hull D.The fatty acid composition of the plasma free fatty acid, triacylglycerol and phospholipid fractions was measured in blood and milk samples taken daily from 3 mares and their foals on Days 1-9 post partum inclusive, and from a total of 12 mares and foals on Days 22, 30 and 51. A rise in the plasma concentrations of triacylglycerol and phospholipid similar to that well documented in other species occurred in the neonatal period. Alterations in the composition of the foal plasma phospholipid after birth lend support to the view that the placenta rather than the fetus could be responsible for the...
Amaniti EM, Diakakis N, Patsikas M, Savvas I.Epiphyseal fracture, also known as epiphysiolysis, is the loosening or separation, either partial or complete, of an epiphysis from the shaft of a long bone. Distal epiphyseal fractures in foals pose a substantial challenge due to their guarded prognosis. This report describes the clinical signs, diagnosis, successful conservative treatment of an 1-month-old, male Skyros pony with an epiphyseal fracture of the right third metacarpal bone (type II Salter-Harris). The owner declined surgical treatment because of financial considerations along with the unfavorable prognosis. Conservative fracture...
Arroyo LG, Vengust M, Dobson H, Viel L.A 10-day-old quarter horse colt was presented for signs of disorientation and inability to nurse. Hydronephrosis/hydroureters, with concomitant pyelonephritis and a severe electrolytes disturbance, were diagnosed. The clinical findings closely resembled those described for a syndrome of transient pseudohypoaldosteronism in human neonates. Un poulain Quarter horse âgé de 10 jours a été présenté pour des signes de désorientation et d’incapacité à se nourrir. Une hydronéphrose/hydrouretères avec pyélonéphrite concomitante et débalancement électrolytique sévère ont été diagno...
Koterba AM, Drummond WH, Kosch P.The basic concepts of diagnosis and treatment in the abnormal neonatal foal are presented. Methods of restraint, sedation, and general nursing care are discussed, as well as more specific techniques of respiratory and circulatory system support.