Johne's Disease (Paratuberculosis) 
This is one of the most insidious of the bacterial diseases of 
cattle. It is characterized by chronicity, intermittent diarrhea, 
emaciation, and eventual death. Diagnoses and control procedures 
are only moderately successful. The incidence is 2.5 percent, and 
the estimated annual cost is $19,900. 
Leptospirosis 
Losses in cattle caused by leptospirosis are due to death, weight 
loss, decreased milk production, and abortion. Although the di- 
sease was first diagnosed in this country within the last 10 years, 
the incidence of 5.6 percent indicates that it is highly contagious. 
The estimated annual loss is over $100 million. 
A high incidence of leptospirosis has been diagnosed in swine in 
some sections of this country. It is apparently a symptomless di- 
sease in swine, but there is evidence that swine sre the seurce of 
infection for cattle. The disease has also been diagnosed in 
horses and goats. 
Mastitis of Cattle 
Mastitis is probably the most important economic disease of cattle 
in this country. It is caused by numerous bacteria as well as by 
a pathogenic yeast. Losses are due to a decrease in milk production, 
loss of weight, animal replacements, and cost of treatment. The 
annual loss is estimated at over $225 million, not including the 
cost of treatment. 
Pasteurellosis of Swine 
The characteristic symptom of the disease is pneumonia. The 
annual loss is based on a 20-percent mortality of the diseased 
animals. 
Shipping Fever of Cattle 
The exact cause of this disease is not known. Lossas are due to 
a decrease in weight and a 20.percent mortality of the animals 
infected. 
Tuberculosis 
Tuberculosis is usually a chronic disease of cattle and swine 
which eventually causes a loss in weight and in milk production, 
and a condemnation of carcasses if lesions are present. The 
causative organism is pathogenic for man. 
