Use of furosemide to obtain bovine urine samples for leptospiral isolation

The use of the diuretic furosemide made it possible to obtain samples of urine from cattle for leptospiral isolations. The drug was injected IV at a dose level of 0.8 mg/kg for heifers and 0.5 mg/kg for calves. The average time to first voiding in heifers was 19 minutes. The average time from the first to the second voiding was 17 minutes. The average time to the first voiding in four calves was 12 minutes; the average time from the first to the second voiding was 10 minutes. A decrease in urinary osmolarity provoked by furosemide created a more favorable condition for the survival of leptospires. Leptospires were isolated in 24 (72.7%) of 33 weekly cultural attempts with the aid of furosemide in three experimentally infected adult cattle. Serovar hardjo was isolated in 16 (57.1%) of 28 weekly cultural attempts with aid of the diuretic in four experimentally infected calves. The recovery frequency was 28.5% from the first voiding and 50% from the second. Leptospires were not isolated from urine obtained from the calves by manual stimulation. Untoward side effects that might have been attributable to furosemide were not observed. Furosemide appears to be well suited to obtain urine samples from cattle for leptospiral isolation.