The difference between the prices realized for cattle from the tick-infested region and the prices of cattle of similar grades from above the quarantine line has ranged from $2.25 to $5 a head at the principal northern live-stock markets, without taking into account the improvement in quality and weight of cattle because of the eradication of the ticks. It can easily be seen that the extermination of the ticks means a large total annual increase in the prices obtained for southern cattle sold in northern markets. In addition to this, the increase in prices of cattle sold locally in the South would represent a large sum. This local increase has been found to amount to from $3 to $15 a head in territory freed from ticks. An agricultural official of one of the Southern States has reported that calves in the tick-free area bring double the prices that can be obtained for similar calves in the tick-infested region.
Heretofore it has been impracticable to improve the quality of southern cattle by introducing fine breeding animals from other sections, because such animals were liable to contract Texas fever and die unless protected by inoculation. Furthermore, it is impossible for animals to attain good growth and to thrive when they are heavily infested with ticks. With the eradication of the ticks, however, the southern farmers are enabled to introduce good breeding animals and to improve the grade of their stock.
There is no longer any doubt that it is entirely practicable to exterminate the ticks throughout the entire region, and the accomplishment of this result will be of tremendous economic advantage not only to the South but to the whole country. The rate of progress depends mainly on two factors— the amounts appropriated by the Federal and State Governments, and the cooperation of the people.
CHRONIC BACTERIAL DYSENTERY.
Chronic bacterial dysentery is a chronic infectious disease of bovines caused by an acid-fast bacillus simulating the tubercle bacillus and characterized by marked diarrhea, anemia, and emaciation, terminating in death.
This disease was observed in the United States for the first time by Pearson in Pennsylvania cattle, and later by Mohler in Virginia cattle, and in an imported heifer from the island of Jersey at the Athenia quarantine station of the Bureau of Animal Industry.
Pearson proposed the name chronic bacterial dysentery for this affection, and it has also been termed Johne's disease, chronic bacterial enteritis, chronic hypertrophic enteritis, and chronic bovine pseudotuberculous enteritis by various European investigators. The disease was first studied in 1895 by Johne and Frothingham in Dresden, but they were inclined to attribute to the avian tubercle bacillus the cause of the peculiar lesions of enteritis which they observed. In 1904 Markus reported this disease in Holland, and subsequently it was observed in Belgium, Switzerland, Denmark, and Great Britain.
Cause.—The bacillus, which has been invariably demonstrated in the intestinal lesions and mesenteric lymph glands in this disease, is a rod about 2 to 3 microns long and 0.5 micron wide. It stains more or less irregularly, like the tubercle bacillus, and moreover the similarity goes further, in that the organism is also strongly acid-fast, which facts led Johne and Frothingham to surmise that the disease was caused by avian tubercle bacilli. However, it has now been plainly demonstrated that the bacillus of chronic bacterial dysentery is readily distinguished from the latter organisms, for while it resembles the tubercle bacillus in form and staining qualities, no one has succeeded in growing it in culture media or in reproducing the disease by injecting experiment animals.
Symptoms.—Probably the first symptom noticed is that the animal is losing condition despite the fact that its appetite is good and the food nourishing. This is soon followed by a diarrhea which, while moderate at first, soon becomes excessive and may be either irregular or persistent, the feces being of the consistency of molasses and passed frequently. In the meantime the hair becomes dry and harsh and the animal falls off considerably in weight. The temperature, however, remains about normal. The appetite does not seem to be greatly impaired until the last few weeks of life, but nevertheless emaciation continues, the animal becomes more and more anemic, great muscular weakness and exhaustion are manifested, and death follows, apparently as the result of the persistent diarrhea and great emaciation. The disease may continue for four or five weeks or may last for a year, or even longer, before death intervenes.