PARASITIC DISEASES OF CATTLE IX PUERTO RICO \j 
not only supplies minerals that are often lacking in local soils but 
also helps to prevent the calves from licking the walls and floors of 
the pen and picking up parasites and disease germ-. 
Improper feeding and management, as well as parasitic diseases, 
cause unthriftiness, emaciation, and stunting in calves. Among the 
causes of failure to raise normal, healthy calves is the common prac- 
tice of feeding them largely or solely on fresh grass. The low- 
protein, bulky forage grasses in common use are unsuited to the 
limited capacity of the stomach of the young calf. These grasses 
should be supplemented with larger proportions of skim milk and 
grain. There are more difficulties to overcome in raising young stock 
in Puerto Rico than in many other localities and climates. 
DISEASES OF CATTLE CAUSED BY PROTOZOA 
PIROPLASMOSIS, TICK FEVER, OR " FIEBRE TEJANA " 
Tick fever is caused by Piroplasma bigeminum, a microparasite 
located in the blood (fig. 2, Aa). These organisms enter the red 
blood corpuscles and cause them to disintegrate. 
Life history. — The piroplasma are transmitted by the common 
cattle tick. The tick becomes infected from the blood of an animal 
that harbors the organism, and the infection is carried through the 
egg to the young ticks of the next generation. These young ticks 
may infect any susceptible animal (bovine) to which they become 
attached. 
Importance. — About one-third of the imported cattle from tick-free 
localities are said to die from this disease. Native cattle, especially 
the higher-bred dairy cattle, suffer from the disease, although the 
attacks are usually of short duration and death does not occur 
as a rule. 
Symptoms. — The first symptom usually noticed is extreme dullness, 
loss of appetite, and, in milking cows, a decided drop in production. 
Other symptoms are a fever temperature which may be as high as 
41.5° to 42.2° C. (107° to 108° F.), constipation, and loss of flesh. 
The feces are usually heavily stained with bile and sometimes with 
blood. The blood itself is pale and watery. A coffee-colored or 
blood-colored urine is characteristic of the disease. 
Treatment. — The sick animal should be placed immediately in a 
cool, shady pen and the ticks removed from the skin. The back and 
sides of the animal may be covered with a thickness of burlap and 
sprinkled frequently with water. Unnecessary driving or rough 
handling should be avoided. A small dose of a saline purge may 
be given if there is constipation. Stimulants to support the heart 
action are indicated. 
Intravenous injections of trypan-blue have been used with good 
results in Africa and South America. The usual dose is 1 gram 
dissolved in 100 cubic centimeters of a sterile physiologic salt solu- 
tion. It should be administered as soon as possible after the symp- 
toms appear. 
Pre rent /on. — This disease can be eliminated by eradicating the 
cattle ticks from the island (p. 22). Cattle, become immune to tick 
fever after recovery from an acute attack. This fact has led to 
the development of several methods of immunizing cattle to the 
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