Urinary diagnostic indices in calves.

OBJECTIVE

To establish reference values for urinary diagnostic indices in healthy calves from birth to 90 days of age.

DESIGN

Prospective field trial.

ANIMALS

12 Holstein heifer calves.

PROCEDURE

Urine and serum samples were collected daily for the first 5 days after birth, then weekly until calves were 90 days old. Urine:serum creatinine ratio, urine:serum urea nitrogen ratio, urine:serum osmolality ratio, fractional clearances of sodium and inorganic phosphate, and urine gamma-glutamyltransferase activity were measured. Data were grouped by age of calves at the time of sample collection: 1 to 5 days old (neonatal period), 7 to 27 days old (suckling period), and 28 to 90 days old (weanling period).

RESULTS

Mean urine:serum creatinine, urea nitrogen, and osmolality ratios were significantly higher during the weanling period than during the other 2 periods. There were no significant differences in mean fractional clearances of sodium among age periods.

CLINICAL IMPLICATIONS

Urinary diagnostic indices calculated for these healthy calves may be used as reference values for early recognition of renal damage or renal failure.