Mammary secretions in normal spontaneous and induced premature parturition in the mare

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 the chances of foal survival in prematurely induced parturition. Mean (+/- se) calcium levels in full term mares that foaled spontaneously (Group 1) were 10.6 +/- 2.7 mmol/litre on the day of parturition. However lower values than this did not necessarily mean parturition would not take place. In Group 2 mares, calcium levels were 4.1 +/- 0.8 mmol/litre just before foaling and rose to 9.2 +/- 1.5 mmol/litre within 20 mins of parturition; an increase of 124 per cent. Group 3 mares, induced prematurely, showed poor foal survival if pre-partum calcium levels were less than 3 mmol/litre. Total protein, albumin and globulin concentrations showed a similar trend but the increase just before or during parturition was much less marked.     

Intensive care of the neonatal foal

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.     

Maturity of the neonatal foal.

The immature foal frequently represents a significant management challenge to even the most experienced clinician. The clinical course typically involves complications to a range of body systems,including the musculoskeletal, respiratory, and gastrointestinal systems. Before the commencement of treatment, it is important to provide the owner with an estimation of short-term and long-term survival, expected costs, and possible complications. Formulation of an accurate prognosis can be a difficult task but is aided by knowledge not only of normal maturation but of the factors that affect this process.     

Urogenital problems in the neonatal foal

The common conditions affecting the urogenital tract of the neonatal foal and their medical and surgical management are described. Early recognition and treatment of serious abnormalities are necessary for a successful outcome in the equine neonate.     

Convulsive and allied syndromes of the neonatal foal

This article discusses the clinical signs, etiology, management, and prognosis for the neonatal foal afflicted with a convulsive or allied syndrome.     

Aspects of pharmacology in the neonatal foal

Other therapeutic agents used in foals for specific diseases are discussed elsewhere. The marked effect of species, age, and degree of maturity on drug metabolism in the neonate reinforces the danger of interspecies extrapolation of pharmacology, the need for information specific for the foal, and the necessity for monitoring drug levels in the individual. Suggested antimicrobial doses are listed in Tables 3, 4, and 6. Recommended doses of anticonvulsants and sedatives are listed in Table 8 and in the article "Intensive Care of the Neonatal Foal." The following are recommendations for drug therapy in the neonate: Avoid unnecessary administration of drug to the dam at parturition because of possible placental transfer of the drug with subsequent effects on the neonate. If possible, avoid unnecessary drug therapy in foals under 30 days of age. Select a drug that undergoes minimal biotransformation (hepatic metabolism) and is not highly protein bound. Owing to probable immunodeficiency in the neonate, broad-spectrum, bactericidal drugs are preferred for treatment of life-threatening infections. Every attempt should be made to identify the etiologic agent so that drug therapy can be based on cultures and sensitivity test results to maximize the benefit-risk ratio. Parenteral (intramuscular or intravenous) drug administration is preferable to oral. Avoid drugs that are known oxidants, which may produce hemolysis or methemoglobinemia. In general, the same or a slightly higher initial dose should be employed in the neonate, but it should be given less frequently than in the adult if it has a high potential to cause toxicity. When possible, individual monitoring of serum levels of potentially toxic drugs should be employed in premature and newborn foals unless specific drug pharmacokinetics are known for that age group.     

The foramen ovale of the foetal and neonatal foal

Hearts from 24 foals were studied; 10 were from foetuses ranging in gestational age from 230 to 322 days and 14 were from newborn and young foals aged between birth and 17 days. The foramen ovale and associated vena caval and atrial structures were examined by scanning electron microscopy. Additional observations were made by light and transmission electron microscopy. A tube-like flap of tissue was observed, extending from the aperture in the caudal vena cava to the lumen of the left atrium. In the younger foetuses, the distal end of this tube was covered with a thread-like network of tissue. In animals nearer to term, the network was replaced by distal fenestrations. Protrusions were seen on the rim of the opening of the tube as it entered the atrium. The role that these may play, together with the significance of cardiac muscle and non-elastic connective tissue in the wall of the tube, were discussed with respect to possible mechanisms of closure of the foramen ovale.     

Prognostic factors in the sick neonatal foal

In the foal, the most common neonatal diseases are responsible for an high non-survival rate. Since intensive care for neonatal foals is usually very expensive an early prognosis for survival at admission or during hospitalization is recommended, as well as a prognosis for future athletic potential. Therefore, prognostic factors for prematurity, septicaemia, other infectious diseases and hospitalized foals are revised and discussed on the base of literature and authors experiences. The advantages and limitations of retrospective and perspective prognostic factors is also presented, and the possible role of new expected factors deducted by the recent advances in the knowledge of main neonatal foal diseases pathogenesis proposed.     

Prognostic factors in the sick neonatal foal

In the foal, the most common neonatal diseases are responsible for an high non-survival rate. Since intensive care for neonatal foals is usually very expensive an early prognosis for survival at admission or during hospitalization is recommended, as well as a prognosis for future athletic potential. Therefore, prognostic factors for prematurity, septicaemia, other infectious diseases and hospitalized foals are revised and discussed on the base of literature and authors experiences. The advantages and limitations of retrospective and perspective prognostic factors is also presented, and the possible role of new expected factors deducted by the recent advances in the knowledge of main neonatal foal diseases pathogenesis proposed.

     

Blood gas and acid-base changes in the neonatal foal

This article reviews what are considered the basic concepts of gas transport, blood gases, and acid-base physiology is most mammalian species. Techniques for the appropriate collection of blood samples for blood gas and acid-base determinations in the newborn foal are described. Guidelines for interpretation of these values in the normal foal and those animals undergoing respiratory and metabolic derangements are provided.     

Volvulus of the large colon in a neonatal foal

A one‐day‐old Thoroughbred colt foal was presented for assessment of abdominal pain and reduced urine output. Physical examination of the foal revealed marked abdominal distension, mild tachycardia, tachypnoea and congested mucous membranes. A marked anechoic peritoneal effusion, intestinal hypomotility and mural thickening of the large colon were detected sonographically. Serosanguinous fluid was obtained by abdominocentesis. After haemodynamic stabilisation, the foal underwent general anaesthesia and exploratory laparotomy and a 720° volvulus of the large colon at the sternal and diaphragmatic flexures was identified. After correction of the volvulus, the intraoperative findings were consistent with nonviability of the affected portion of the colon. The owner declined partial colon resection and elected for euthanasia of the foal. Although rare in neonatal foals, large colon volvulus should be considered in foals with signs of abdominal pain, abdominal distension and ultrasonographic findings of colonic mural thickening and luminal distension.     

Hypothyroidism and respiratory insufficiency in a neonatal foal

Hypothyroidism was diagnosed in a neonatal Thoroughbred foal that was weak, hypothermic, and septicemic. Administration of thyroid-releasing hormone elicited attenuated increases in concentrations of free and total triiodothyronine and thyroxine, as compared with a clinically normal, age-matched foal. The foal died of apparent respiratory insufficiency, pre- and postmortem findings compatible with hypothyroidism included hypothermia, large thyroid glands with distended, colloid-filled follicles, and severe, diffuse atelectasis, with thickened alveolar septae and degenerating alveolar squamous epithelial cells.     

Study of the hyaloid apparatus in the neonatal thoroughbred foal

Over 80 per cent of 169 neonatal thoroughbred foals had some part of the hyaloid artery present bilaterally and its degree of completeness, colour and character was statistically symmetrical. The complete artery was present in over 60 per cent of the foals. The incidence of the hyaloid artery and its completeness, colour and character were related to the age of the foal. The hyaloid system atrophies in the early stages of the neonatal period and generally its presence did not cause any significant ocular problems. The presence and morphology of the posterior pupillary membrane was highly correlated with the presence, completeness, colour and character of the hyaloid artery.     

The influence of additional fat in the diet of sows before and after parturition on piglet viability and performance

Two hundred and six mature sows were used to evaluate the effect of adding a total of 3 kg of fat to sow diets for an average of eight days before and seven days after parturition on piglet viability and performance.The addition of fat to the diet of sows had no effect on the percentage of piglets born alive, individual piglet birth weight, weight of the piglet at three weeks of age or the weaning to service interval in the sows. However, there was a significant increase in piglet survival (3.4%) between treated and control sows. Birth weight had a marked effect on piglet survival but there was no indication of a greater effect of added fat in the sows' diet on the survival of smaller piglets. A number of piglets were cross-fostered but fostering had no effect on piglet mortality. A comparison of the mortality of piglets born from sows receiving added fat and reared on controls and vice versa indicated that the major benefits of additional fat in the sow diet were effected in utero rather than via an increase in the quality of the sows' milk.     

Hematology, blood typing, and immunology of the neonatal foal

Hematologic parameters change during the first 10 days of life. Erythrocytes increase in number but decrease in size and hemoglobin concentration. The PCV, hemoglobin, and platelet count also decrease. Total blood and plasma volume and, to lesser extent, erythrocyte volume decrease. Normal neonatal foals may have immature neutrophils (up to 5 per cent bands), and their early rapid rise in neutrophil numbers may be accompanied by a lymphopenia. Monocytes, eosinophils, and basophils are all absent or low initially. Infectious processes can cause rapid and variable changes in the leukogram. However, elevation of fibrinogen levels may lag behind the development of an inflammatory process, and this parameter should not be relied on for early evidence of infection. After 12 hours of life, there is generally a decrease in serum concentrations of Na, Cl, iron, creatinine, BUN, plasma protein, and possibly calcium. LDH, SAP, P, bilirubin, and glucose concentrations are all higher in foals than in mature horses. Creatinine may actually be elevated during the first 12 hours of life and then decreases. If azotemia, hypochloremia, hyponatremia, and hyperkalemia are found, ruptured bladder with uroperitoneum should be suspected. The creatinine concentration is preferable to BUN determination for diagnosis of this condition. Blood typing is useful for diagnosis of NI, determination of blood compatability between donor and transfusion recipient, and for verification of parentage for breed registries. Several techniques are available. Several tests are available for evaluation of the foal's immunoglobulin levels and confirmation of passive antibody transfer. Because foals suffering from FPT are more predisposed to infections, their immunoglobulin status should be determined as early as possible so that additional colostrum or plasma can be administered as needed. Neonatal isoerythrolysis is uncommon but is an important immunologic syndrome that often results in a fatal hemolytic crisis. If one suspects the condition may be likely, the optimal time for testing the mare is during the last 2 weeks of gestation. If the foal's dam is shown to have alloantibodies against a panel of known erythrocyte alloantigens, prevention is possible by feeding colostrum from another mare. If a foal develops NI, further colostrum ingestion from the dam must be prevented. Good nursing care, minimizing stress, and adequate frequent feedings are essential; prophylactic antibiotics should be used, and transfusion may be necessary.     

Preliminary study on the pharmacokinetics of phenobarbital in the neonatal foal

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 (+/- se) half-life of 12.8 +/- 2.1 h. The mean (+/- se) volume of distribution was 0.86 +/- 0.026 litres/kg bwt and mean (+/- se) total body clearance was 0.0564 +/- 0.0065 litres/kg bwt/h. Sedation was noticed 15 to 20 mins after the beginning of infusion and lasted for up to 8 h. All foals could be aroused and could walk although they were ataxic for the first 1 to 2 h. A degree of delayed hyperexcitability occurred 3 to 8 h after infusion. In equine neonatal seizure disorders it is recommended to use a loading dose of 20 mg/kg bwt of phenobarbital, followed by maintenance doses of 9 mg/kg bwt at 8 h. With this regimen, average steady state serum phenobarbital concentrations should range between approximately 11.6 and 53 micrograms/ml. Phenobarbital serum concentrations should be monitored following the loading dose and 24 h after initiating the maintenance doses to check that levels remain within the suggested (human) therapeutic range of 15 to 40 micrograms/ml.     

Omphalophlebitis and osteomyelitis associated with Klebsiella septicemia in a premature foal

Gram-negative neonatal septicemia was diagnosed in a premature Standardbred colt. Clinical signs included lethargy, weakness, loss of suckle reflex, tachypnea, and injected mucous membranes. Sequelae included pneumonia, omphalophlebitis, septic arthritis, and osteomyelitis. Prepartum maternal uterine infection, premature delivery, abnormal parturition with premature fetal membrane separation, and failure of passive transfer of colostral immunoglobulins increased the foal's risk for developing sepsis. Treatment included administration of moxalactam disodium and cefadroxil. The clinical efficacy of cephalosporin antibiotics in the treatment of gram-negative sepsis is discussed.     

Anaphylaxis and systemic inflammatory response syndrome induced by inadvertent intravenous administration of mare's milk in a neonatal foal

Objective – To describe the diagnostic procedures, therapeutic management and successful outcome of a case of anaphylaxis induced by the inadvertent intravenous (IV) administration of mare's milk to a neonatal foal. Case Summary – A 3‐day‐old Thoroughbred colt was presented for treatment of bilateral flexural limb deformities of the forelimbs. Because the foal was unable to ambulate initially, mare's milk was administered via nasoesophageal tube feedings during treatment of the musculoskeletal disorder. Anaphylaxis resulted after unintentional administration of a bolus of 150 mL of mare's milk through a jugular catheter. Aggressive therapy for anaphylaxis and careful monitoring resulted in the successful recovery of the foal after 9 days of intensive care. New or Unique Information Provided – This case is the first published report to describe the effects of accidental IV administration of mare's milk to a neonatal foal. Medical errors are commonly reported in pediatric medicine; the intent of this report is to raise awareness of medical errors and student education in equine medicine as well as describe the therapy and outcome of anaphylaxis induced by IV administration of mare's milk in a neonatal foal.     

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.