URINARY DIAGNOSTIC INDEXES IN CALVES

Objective-To establish reference values for urinary diagnostic indices in healthy calves from birth to 90 days of age. Design-Prospective fi eld trial. Animals-12 Holstein heifer calves. Procedure-Urine and seru m samples were collected daily for the first 5 days after birth, then weekly until calves were 90 days old. Urine:serum creatinine ratio, ur ine:serum urea nitrogen ratio, urine:serum osmolality ratio, fractiona l clearances of sodium and inorganic phosphate, and urine gamma-glutam yltransferase activity were measured. Data were grouped by age of calv es 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 osmol ality 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 Impli cations-Urinary diagnostic indices calculated for these healthy calves may be used as reference values for early recognition of renal damage or renal failure.