Johne's frequently are more subject to heavy parasite loads. Any adult goat which is continually parasite-infected should be tested for Johne's Disease . Clinical signs of this disease do not appear until goats are yearlings and sometimes much later. Kids can also become infected through the colustrum and milk of Johne's -carrying mothers. If a kid receives a high dose at an early age, the kid will most likely begin shedding the disease in its feces and showing clinical signs of infection at an earlier age than a kid who received a low dose of the bacteria.
Some goats are carriers and never show clinical signs of the illness.
There seems to be an age-related resistance to Johne's Disease , but older goats can become infected, particularly in overcrowded and unsanitary conditions. Generally speaking, overt signs of infection begin to show after many years of shedding the bacteria, particularly if the animals are managed well, with good nutrition, clean conditions, no overcrowding, and minimal stress in their lives. Once it is evident that infection is present, the Johne's -infected goats usually live less than one year and ultimately die from their inability to absorb nutrients from their intestinal tracts. The mid-stage, from age two to four, is the really dangerous time, because those goats look reasonably well but are shedding the bacteria like crazy. Johne's is rarely seen in goats over seven years old.