Hemostatic Indices in Healthy Foals from Birth to One Month of Age

Abstract

Hemostatic indices were determined in 45 healthy light breed foals, from birth to 1 month of age, and in 20 healthy adult (> 2 years of age) light breed horses. Blood samples were obtained from each foal at 4 ages: 1) < 24 hours, 2) 4-7 days, 3) 10-14 days, and 4) 25-30 days. The following hemostatic indices were determined: platelet count; prothrombin and activated partial thromboplastin times; activity concentrations of protein C, antithrombin III, plasminogen, alpha-2 antiplasmin, tissue plasminogen activator, and plasminogen activator inhibitor-1; plasma protein C antigen and fibrinogen concentrations; and serum fibrin degradation products concentration. Prothrombin and activated partial thromboplastin times were significantly longer at birth than in older foals. The plasma concentrations of the following were significantly lower at birth than in older foals: antithrombin III, plasminogen and tissue plasminogen activator activities, protein C antigen, and fibrinogen. Concentrations of the following were significantly higher at birth than in older foals: protein C and plasminogen activator inhibitor-1 activities and fibrin degradation products. These results indicate that hemostatic indices of neonatal foals differ significantly from those of older foals and adults. With the exceptions of antithrombin III and tissue plasminogen activator activities, all hemostatic indices measured in foals at 1 month of age were equivalent to adult values.

Prospective Evaluation of Coagulation in Critically Ill Neonatal Foals

“…1,17 The difference in fibrinogen values is likely due to different assay techniques. The 2nd limitation is the bias, which may have been introduced by grouping all samples together.…”

“…1,17 Healthy foals have prolonged prothrombin time (PT) and activated partial thromboplastin time (aPTT), combined with decreased protein C, antithrombin activity (AT), and fibrinogen concentration compared with adults, similar to differences in coagulation between neonatal and adult human patients. 14,16,18 Foals with presumed septicemia have prolonged PT, aPTT, and increased concentration of FDPs with decreased AT and protein C concentration, but platelet and fibrinogen concentrations are not indicative of consumptive coagulopathy.…”

Age-Related Developmental Clotting Profile and Platelet Aggregation in Foals Over the First Month of Life

“…Despite homeostatic mechanisms that function to maintain blood parameters within physiological levels, some changes are likely to occur [4]. In particular, it was demonstrated that hemostatic factors are reduced in several animals [2,5] including foals [6,7].…”

Clotting Profiles in Newborn Maltese Kids during the First Week of Life

“…For instance, in foals, low levels of coagulation factors and prolonged prothrombin (PT) and activated partial thromboplastin times (aPTT) are present at birth. 5 Knowledge of these differences is essential to the diagnosis of thrombotic and hemorrhagic problems of the neonate. However, defining normal values poses several difficulties, including age dependency, sample size and method of collection, and assay technique.…”

“…However, defining normal values poses several difficulties, including age dependency, sample size and method of collection, and assay technique. 5 Newborn animals are subjected to a number of different stimuli that could possibly lead to activation of the hemostatic system: stress with adrenergic stimulation, acidosis, hypoxia, thermal changes, and possibly, tissue factors liberated during the process of birth and placental separation. 24 Many studies have been carried out on the development of the coagulation system in lambs, 3,16,18 but little is known about kids.…”