Plasma, red blood cell, total blood, and extracellular fluid volumes in healthy horse foals during growth.

This study examines the changes in various blood and fluid volumes within healthy, growing horse foals from 2 days to 24 weeks of age.

Methodology

• The researchers studied the change in plasma, red blood cell (RBC), total blood, and extracellular fluid (ECF) volumes in seven healthy foals over the course of their growth from 2 days to 24 weeks of age.
• They used two different chemical compounds, Evans blue dye and sodium thiocyanate, to estimate plasma and ECF volumes respectively.

Findings

• Absolute plasma volume remained stable from when the foals were 2 days old to when they were 2 weeks old, but increased steadily as the foals grew to 24 weeks of age.
• Similarly, the absolute volumes of RBC and total blood decreased initially, between 2 days and 2 weeks of age, and then gradually increased through 24 weeks of age.
• The absolute volume of ECF progressively increased from 2 days to 24 weeks of age. However, relative to body weight, plasma, RBC, and total blood volumes reduced during the growth period.
• Relative to body weight, ECF volume decreased during the first 12 weeks but then plateaued over the following 12 weeks.
• The researchers noted a close relationship between the age and body weight of the foals and their plasma, RBC, total blood, and ECF volumes, suggesting these factors significantly influence these parameters during the early growth stages of foals.

Implications

• The findings are useful for understanding the normal physiological changes that occur during early growth and development in foals.
• More practically, the relationship established between the different fluid and blood volumes and age can be utilized as a tool to evaluate and manage fluid balance alterations in foals, aiding in their healthcare and wellness.