Resumen

MACCHI, Valentina et al. Abortion in beef cattle in Uruguay: evaluation of leptospirosis and other infectious agents. Veterinaria (Montev.) [online]. 2025, vol.61, n.224, e205.  Epub 01-Dic-2025. ISSN 0376-4362.  https://doi.org/10.29155/vet.61.224.7.

Leptospirosis is a well-recognized bacterial zoonosis caused by Leptospira spp. In cattle, its occurrence is often associated with reproductive disorders. This study aims to determine the association between abortion, seropositivity to local strains, and urinary shedding levels of pathogenic Leptospira in unvaccinated beef cows in Uruguay. A case-control study was conducted in 31 livestock farms with no history of leptospirosis vaccination for at least one year. In each farm, 25 pregnant cows with less than three months of gestation were monitored. Three visits were conducted throughout the cows’ gestation: during the first third, the second third, and postpartum. During each visit, aborted cows were identified, and blood and urine samples were collected from these cows and two companions per aborted cow. Serological diagnosis was performed for Leptospira spp. (microscopic agglutination test), bovine infectious rhinotracheitis, bovine viral diarrhea, and Neospora caninum (ELISA). Urine samples were analyzed by qPCR for the detection of pathogenic Leptospira. A logistic regression was performed, considering the farm as a random variable. The analysis included 35 aborted cows and 61 control cows. Aborted cows had 8.06 times higher odds of being seropositive to the Pomona serogroup compared to pregnant cows or those that had delivered a full-term calf (p = 0.01). A strong association was also observed with seropositivity to Neospora caninum, as aborted cows had 11.31 times higher odds of being seropositive to this protozoan compared to the control group (p < 0.01). While an association between leptospirosis and abortion in beef cattle was established, further targeted studies are needed to more precisely determine the impact of this disease on livestock production systems.

Palabras clave : Reproductive losses; Cattle farming; Bovine leptospirosis.

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