Co‐infection with bacteria in the M. avium complex has been reported to reduce the sensitivity of SICCT and gamma interferon (IFN‐γ) testing for M. bovis in small‐scale studies, through cross‐reaction of antigens and an increase in response to the avian tuberculin of the SICCT test (Álvarez et al., 2009; Hope et al., 2005). This evidence concerns the gene IFNG and coinfection.