Although colostrum has been used to detect specific immunoglobulin (Ig) G to Mycobacterium avium subsp. paratuberculosis (MAP) in cattle, confounding, non-specific reactions can be a problem. The objectives of this study were to determine the proportion of non-specific ELISA reactions in samples of colostrum taken between 0 and 4days-in-milk (DIM), and to assess the probability of an animal testing positive for MAP specific IgG over this time-period. Non-specific reactions were found in 3/365 (0.8%) of samples. The odds of an animal testing positive on day of calving were 130 times higher than at 4 DIM. The findings suggest colostral samples may have enhanced diagnostic potential over milk samples in determining if cattle have been exposed to or infected with MAP.
Veterinary Journal, 2013, Vol 197, Issue 3, p. 889-891