There are a range of testing options available to dairy farmers to verify the Johne’s status of individual farms.
The MAP bacteria is shed in the faeces of Johne’s infected animals. Initially it is shed in small numbers and intermittently with numbers of bacteria and frequency of shedding increasing as the disease progresses. Faecal testing to look for the MAP bacteria can be used as a screening tool but is most commonly used in individual animals to confirm infection.
A faeces sample is taken and cultured in the laboratory to see if MAP is present. MAP is a slow growing bacteria, so it takes up to eight weeks to obtain a result.
A faeces sample is taken and subjected to a PCR test in the laboratory which looks for the DNA of the MAP bacteria. Advantages of this technique include a low detection limit and a rapid turnaround time when compared to culture.