DAIRYING IN PORTO RICO. V 
known as tick fever. Young imported cattle stricken with the lever 
come through with small losses if they are carefully looked after for 
a few months and fed largely on green grasses. The older imported 
cattle, however, are more severely attacked, and there is a greater 
percentage of loss among them. Introduced cattle become tick in- 
fested soon after their arrival unless they are given very special at- 
tention and care. Unfortunately, the average Porto Rican farmer 
is not prepared to give his cattle the best treatment, and great losses 
are common among the imported cattle. In the few instances where 
the cattle do not succumb to tick fever, their vitality is lowered to 
such an extent that they seldom fully recover. 
The tick is the great enemy of the cattle industry. It plays havoc 
with the health of the cattle, drawing blood that would otherwise 
produce milk or flesh and impeding circulation. The animals lose 
in flesh and energy and soon become a source of expense to the owner, 
who is obliged to feed an unusually heavy ration to maintain life. 
Cattle that are dipped at intervals show a decided gain in weight 
over untreated animals. The work of dipping cattle to free them 
from the tick is not only very effective, but it is also easy and prac- 
tical. There are now about 100 dipping tanks on the island, and the 
necessity of exterminating the tick is beginning to be realized. 
Stringent measures should be adopted toward this end. An energetic 
campaign, conducted by the island government, could be carried on 
(1) by detailing men to all sections of the island to dip at regular 
intervals every animal within a given area until it is cleaned; and 
(2) by quarantining each cleaned section until the whole island has 
been covered. When the tick is unable to secure bovine blood for one 
generation it can not reproduce and dies. An area in which this 
occurs then becomes free from infestation until another tick is 
brought in. Once the tick is eradicated in Porto Rico, quarantine 
regulations can be adopted at little cost to keep it out. 
TUBERCULOSIS. 
With the exception of tick fever there is no especially serious dis- 
ease of cattle in Porto Rico. No general statistics are available as to 
the presence of bovine tuberculosis, but it is thought that the island 
is comparatively free from this disease. Two herds of native cattle 
belonging to the agricultural college and to the experiment station 
were tested, but neither herd contained reactors. 
THE LIVER FLUKE (Fasciola hepatica). 
Liver rot, a disease caused by a small parasite known as the liver 
fluke (Fasciola hepatica), commonly affects the cattle in some sec- 
tions of Porto Rico. At the slaughterhouse these parasites are dis- 
cernible in great numbers in the livers of the dead animals. The 
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