LEPTOSPIROSIS OUTBREAK IN DAIRY CATTLE DUE TO LEPTOSPIRA SPP. SEROVAR CANICOLA: REPRODUCTIVE RATES AND SEROLOGICAL PROFILE AFTER TREATMENT WITH STREPTOMYCIN SULFATE

Abstract

ABSTRACT The objectives of the present trial were to evaluate the reproductive parameters in a Holstein bovine herd affected by leptospirosis during the outbreak of abortion and stillborn fetus and treated with streptomycin sulfate. Animals were divided in 2 groups of 10 cows each: G1, treated with streptomycin sulfate 25 mg/kg/lw for 3 days by IM route; and; G2, untreated control. Serum samples were collected on the onset of abortions and after that every 15 or 30 days until completing 270 days. Samples were analyzed by means of MAT microscopic agglutination test that showed sera conversion to serovar Canicola with titers ranging from 100 to 51,200; 7/20 of the urine samples were positive for Leptospira spp. by PCR After streptomycin sulfate therapy, the outbreak ended and urine samples also got negative to PCR and no fetus samples were positive in either techniques. However, it did not influence the evolution in antibody titers of serological profiles in both groups, which got negative after around 200 days of the onset of symptoms. Although there was no significant difference of the frequency of pregnancy/AI and calving/pregnancy rates between treated and untreated groups (p > 0.05), reproductive rates were lower in the untreated group.