Causes of abortion, stillbirth, and perinatal mortality in horses

Juffo G.D., Antoniassi N.A.B., Bassuino D.M., Gomes D.C., Snel G.G.M., Pavarini S.P. & Driemeier D. 2022. Causes of abortion, stillbirth and perinatal mortality in horses. Pesquisa Veterinaria Brasileira 42:e06808, 2022. Setor de Patologia Veterinaria, Faculdade de Veterinaria, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9090, Porto Alegre, RS 91540-000, Brazil. E-mail: davetpat@ufrgs.br Causes of abortion, stillbirth, and perinatal mortality in horses were investigated in the Department of Veterinary Pathology of the Federal University of Rio Grande do Sul (SPV-UFRGS) from 2000 to 2015. In this period, 107 cases were analyzed using macroscopic, microscopic, and complementary tests. Of these, 77 were aborted fetuses, 16 were stillbirths, and 14 were perinatal deaths. Conclusive diagnosis was established in 42.8% of the fetuses analyzed, with 28.6% classified as infectious origin, 9.1% as non-infectious, and 5.1% as other. Bacterial infections, especially those related to Streptococcus spp. were the most frequently observed. In stillborn foals, diagnosis was established in 62.5% of cases, and 50% of these were related to non-infectious causes, such as dystocia and birth traumas. As for perinatal mortality, a conclusive diagnosis was reached in 78.57% of cases, and infectious causes associated with bacterial infections accounted for 64.1% of these diagnoses.