Haematological findings in pregnant, postparturient and nursing mares

Abstract

Venous blood samples were collected from 16 Thoroughbred and Quarter Horse mares during late pregnancy (approximately one month before parturition), approximately 6 h after parturition, one month after parturition and 4 months after parturition when the foals were weaned. There were no significant differences over time for haematocrit, mean cell volume, mean cell haemoglobin concentration, platelet count or mean platelet volume. The icterus index was significantly higher, and the total plasma protein concentration was slightly lower, during late pregnancy than when nursing. Plasma fibrinogen concentration and total leucocyte counts were highest shortly after birth. Results from differential leucocyte counts revealed that the increased total leucocyte count measured shortly after birth was the result of increased numbers of neutrophils. There were no significant differences in absolute lymphocyte, monocyte or basophil counts, but the number of eosinophils was significantly lower shortly after birth. Total serum iron concentration and percentage saturation of transferrin with iron were highest shortly after birth. There was no significant difference in iron binding capacity over time. Serum ferritin and cortisol concentrations were lowest during late pregnancy, but the mean ferritin value was not significantly different from other time periods. The addition of iron and other mineral supplements to the basic concentrate fed at the University of Florida Horse Research Unit did not have a measurable effect on any haematological parameter evaluated in mares.