Indices of renal function: values in eight normal foals from birth to 56 days.

This study investigated the renal function in eight healthy foals from birth up to eight weeks old, providing valuable baseline information for diagnosing and managing kidney disease and raised levels of nitrogen-containing compounds.

Study Methodology

• The research involved collecting a series of blood and urine samples from eight normal, healthy foals from birth to eight weeks of age.
• The blood chemistry related to kidney function was assessed, alongside the physical and chemical attributes of the foals’ urine.

Findings in the First Four Days

• During the initial four days of the foals’ lives, there was a wide variance in values, making the suggestion of typical normal values impractical.
• Levels of serum urea and plasma creatinine, both indicators of kidney function, fell substantially to levels lower than those previously reported for healthy adult horses.
• The urine of the foals, initially mildly concentrated (hypersthenuric) at birth, rapidly turned dilute (hyposthenuric).
• The research also recorded a significant presence of protein in the urine (proteinuria) in the first 48 hours.

Findings After the First Four Days

• After the initial four-day period, the clinicopathological values became more stable.
• Urea and creatinine levels remained below adult horse levels, and the urine remained dilute.
• Despite some variations over time, the urine, in general, had greater activity of gamma-glutamyl transpeptidase (GGT) and alkaline phosphatase (AP), two enzymes prominent in the kidneys, compared to adult horses.

Key Differences Between Foal and Adult Horse Values

• Plasma potassium, the creatinine clearance ratio of potassium (% Cr K), serum inorganic phosphate, and the creatinine clearance ratio of phosphate (% Cr PO4) were all greater in foals than in adult horses.
• The concentration of chloride in plasma and the creatinine clearance ratio of chloride (% Cr Cl), on the other hand, were lower in foals than in adult horses.
• Additionally, the urine in foals was more acidic, and contained more epithelial cells and calcium oxalate crystals, compared to the urine of adult horses.

Conclusion

• This study offers useful baseline data that can be utilized in diagnosing and managing kidney diseases and azotaemia (an excessive amount of nitrogen-containing compounds in the blood) in foals.