Johne’s Disease

Johne’s Disease

  • Johne’s disease is a gastrointestinal disease of ruminants including cattle, sheep, and goats caused by the bacterium Mycobacterium avium paratuberculosis (MAP).
  • In cattle, it causes decreased milk production, chronic diarrhea, weight loss, and death.
  • In sheep and goats, the most consistent clinical sign is chronic weight loss despite a good appetite. The diarrhea typically seen in cattle is not common in sheep and goats, but the disease still leads to death.
  • Young animals are more susceptible than adults, however animals of any age can become infected. Sheep and goats will generally show signs by the time they are one year of age, while cattle are not likely to develop clinical disease until they are at least two years old.
  • There is no cure for Johne’s disease. Infected animals shed the organism through feces, creating a possible route of exposure for the rest of the herd/flock.

Sample Types

  • Milk
    • Fresh, frozen or preserved
    • Individual or bulk tank
    • Pooling available for AntelBio™️ STRATA-G™️ Johne’s PCR test
  • Serum ( Fresh)
  • Fecal (Fresh or frozen) Pooling available – up to 5 samples per test
  • Sheep and goats can only be tested with the blood ELISA


  • Test milk or blood at dryoff or in early lactation
  • Test fecal samples at any age


  • Milk and blood ELISA available within 5 days of sample receipt
  • AntelBio™️ STRATA-G™️ Johne’s PCR  (milk or fecal) available within 10 days of sample receipt
  • Reported as Positive, Negative or Suspect
  • Animals with a Suspect result should be retested at a later date.
  • Animals that are within 7 days of freshening have a high probability of giving false positive results when tested because of the presence of colostral antibodies.
Test Type Positive Negative Suspect
Milk ELISA >0.3 <0.2 0.2 – 0.3
Bulk Milk ELISA >0.1 <0.1
Blood ELISA >0.55 <0.45 0.45 – 0.55
Bulk Milk PCR <41 >41
Fecal PCR <38 Undetected 38 – 40
Test Type Positive Negative Suspect
Blood ELISA >0.55 <0.45 0.45 – 0.55


  • Individual ELISA (milk, blood) $6.50/sample
    • Multiple test discounts! $11 for two ELISAs on the same sample; $15.00 for 3 ELISAs
  • PCR (milk, pooled, or bulk milk) $50/sample
  • AntelBio™ STRATA-G™ Johne’s PCR (fecal) $40/sample
  • AntelBio™ STRATA-G™ Johne’s PCR  (pooled fecal) $12/sample; minimum 3 samples, maximum 5 samples
  • Testing billed upon sample receipt
  • $10 sample submission fee per order

Submit Samples

CentralStar’s laboratories provide sample analyses on milk, blood, fecal, and tissue samples for a variety of production, disease and health-related traits. More than 6 million samples are processed annually using state-of-the-art equipment and techniques including infrared spectroscopy, flow cytometry, ELISA, PCR, and more.

Diagnostic tests are intended to identify diseases for animal health, and do not determine the “safety” of milk.