Bayesian estimation of the true prevalence of paratuberculosis in Hungarian dairy cattle herds.

Paratuberculosis is a chronic incurable disease caused by Mycobacterium avium subsp. paratuberculosis (MAP), which leads to extensive economic losses on dairy farms, and may also pose serious public health risk to the consumers. The aim of our study was to estimate the true prevalence of paratuberculosis in commercial dairy cattle herds participating in a voluntary MAP testing programme that started in February 2018 in Hungary.

Associations between management practices and major reproductive parameters of Holstein-Friesian replacement heifers.

The aim of this study was to assess the relationship between the reproductive management practices and the performance of replacement heifers on large commercial dairy farms. The individual data of 14,763 heifers, first inseminated in 2014, were analysed from 33 Holstein-Friesian dairy herds in Hungary. The relationships between management practices and major reproductive parameters (age at first service, AFS; age at first calving, AFC; conception risk to first insemination, CR1; and pregnancy status at 20 months of age) were examined by mixed-effects models, with the herd as the random effect.

Exact inference for the risk ratio with an imperfect diagnostic test.

The risk ratio quantifies the risk of disease in a study population relative to a reference population. Standard methods of estimation and testing assume a perfect diagnostic test having sensitivity and specificity of 100%. However, this assumption typically does not hold, and this may invalidate naive estimation and testing for the risk ratio.