Microcytosis, hypoferremia, hypoferritemia, and hypertransferrinemia in standardbred foals from birth to 4 months of age.

This study was conducted on 24 newborn Standardbred foals that were randomly assigned to receive either a placebo supplement or an iron supplement. The researchers followed the health and hematologic changes of the foals from birth to 4 months of age.

Group allocation and treatment

• The researchers randomly divided the foals into two groups. One group received a placebo treatment while the other got an iron supplement that contained 248mg of iron.
• Both supplements were administered four times over the course of 2 and 3 weeks post birth.

Hematologic observation and Health Monitoring

• The foals’ hematological variables and overall health were monitored until they reached the age of 4 months.
• During the first 2 weeks after birth, a decrease was observed in the mean PCV (Packed Cell Volume—a measure of the proportion of blood volume that is occupied by red blood cells) of the foals regardless of the treatment group. But these values remained within the normal range for adult horses.
• The size of erythrocytes (red blood cells) in foals for the first six weeks after birth was smaller compared to those in adult horses. However, foals exhibited a higher glucose-6-phosphate dehydrogenase activity—a key enzyme in the red blood cell that helps protect from oxidative damage—than adult horses.
• There was a homogeneous population of small-sized erythrocytes in foals, as indices of anisocytosis (variation in red blood cell size) were lower in foals compared to adult horses.

Iron and Ferritin Levels

• The mean serum iron concentration, which is the measure of the amount of iron in the blood, was lower in two-week-old foals of both groups and in four-week-old foals from the placebo-treated group than the normal range for adult horses.
• The total iron-binding capacity values, a measure of the blood’s ability to bind iron with transferrin, was above the normal range for adult horses in newborn foals, and this continued through the first 4 months.
• There was a decrease to below the reference range in the transferrin saturation percentage, which is the percentage of transferrin that is saturated with iron, in foals from 2 weeks to 4 months after birth.
• At birth, the serum ferritin concentration, which reflects the amount of stored iron, was higher than the adult horse reference range but decreased to the normal range in one day old foals. Starting from 2 through 6 weeks after birth, the ferritin concentration values were below the normal range for adult horses.