Detection of Brucella spp. in compost-bedding pack barn and its relationship with infections in dairy cows during the transition period.

Compost-bedded pack barn (CBP) is a used intensive system for dairy cow confinement, however, information about the possible role of the bed in the maintenance and transmission of pathogens among housed animals is still scarce. This study investigates the presence of Brucella spp. in dairy cows in the transition period housed in CBP and the detection of the pathogen in the CBP. The analyzes were conducted using samples of CBP and samples from cows up to 45 days post-partum from 20 different farms in Goiás and Minas Gerais states, Brazil. Animals were tested for the presence of anti-Brucella antibodies. Samples of vaginal swab, endometrial sample and CBP were tested for the presence of Brucella spp. using conventional PCR targeting the bscp31 gene, as a screening test, and the real-time PCR targeting the IS711 gene, as confirmatory test. A total of 16 [16/20 (80 %)] properties exhibited at least one positive animal in at least one test (serology or molecular tests), and four [4/20 (25 %)] of these properties had at least one positive animal in at least two tests performed. Additionally, three CBP [3/44 (6.88 %)] showed PCR positive result to Brucella spp. The results demonstrated the presence of Brucella spp. in sample collected from dairy cows in transition period housed in CBP and the bed of the system, suggesting the CBP may have a role in brucellosis transmission in the system, by favoring the spread of the agent and transmission to other housed cows.