Any animals showing diarrhea and weight loss should be culled immediately or tested and isolated pending test results. Manure from infected adults should be applied only on cropland to be tilled, and youngstock must be isolated from contaminated barnyards, pastures, and water. Halting the infection cycle in an infected herd requires that calves be removed from dams immediately after birth and be raised as replacements completely separated from the adults and the manure contaminated environment. Once a control program is initiated, intradermal skin testing may be useful in screening young calves. A positive reaction in these animals would indicate likely exposure and the need for further testing.
Indications are that calves can become infected immediately after birth.
Infection in the uterus before birth has been documented in clinical Johne's cows, but is apparently rare in subclinically infected cows. A higher percentage of offspring from infected dams become infected due to increased exposure of the calf to contaminated feces. The organism has been isolated in the semen of bulls, although spread of infection has not been demonstrated by artificial insemination. If it is necessary to buy replacement cattle, they should be purchased from known negative Johne's herds or herds without a history of the disease that have been screened using one of the quicker, less sensitive tests. This may become more routine as support grows for a voluntary program certifying that cattle have disease free status.