INFECTIOUS DISEASES OF CATTLE. 465 



Symptoms. — After a period of exposure to infected soil, which may 

 Vary from thirteen to ninety days, and which will be more fully dis- 

 cussed further on under the subject of cattle ticks as bearers of the 

 Texas-fever parasite, the disease first shows itself in dullness, loss of 

 appetite, and a tendency to leave the herd and stand or lie down alone. 

 A few days before these symptoms appear the presence of a high fever 

 may be detected by the clinical thermometer. The temperature rises 

 from a normal of 101° to 103° F. to 106° and 107° F. There seems to 

 be little or no change in temperature until recovery or death ensues. 

 The period of high temperature or fever va.'ies considerably. As it 

 indicates the intensity of the disease process going on within, the 

 higher it is the more rapid the fatal end. When it does not rise above 

 104° F. the disease is milder and more prolonged. 



The bowels are mostly constipated during the fever; toward the 

 end the feces may become softer and rather deeply tinged with bile. 

 The urine shows nothing abnormal during the course of the disease 

 until near the fatal termination, when it may be deeply stained with 

 the coloring matter of the blood. (Hemoglobinuria; see PI. XL VII, 

 fig. 3. ) Although this symptom is occasionally observed in animals 

 which recover, yet it may generally be regarded as an indication of 

 approaching death. The pulse and respiration are usually much more 

 rapid than during health. 



Other symptoms in addition to those mentioned have been described 

 by observers, but they do not seem to be constant, and only the above 

 are nearly always present. As the end approaches emaciation becomes 

 very marked, the blood is very thin and watery, and the closing of 

 any wound of the skin by clots is retarded. The animal manifests 

 increasing stupor and may lie down much of the time. Signs of 

 delirium have been observed in some cases. Death occurs most fre- 

 quently in the night. 



The course of the disease is very variable in duration. Death may 

 ensue in from three days to several weeks after the beginning oi the 

 fever. Those that recover ultimately do so very slowly, owing to the. 

 great poverty of the blood in red corpuscles. The flesh is regained 

 but very gradually, and the animal may be subjected to a second 

 though mild attack later on in the autumn, which pushes the full 

 recovery onward to the beginning of winter. 



In the mild type of the disease, which occurs in October and Novem- 

 ber, symptoms of disease are well-nigh absent. There is little if any 

 fever, and if it were not for loss of flesh and more or less dullness the 

 disease might pass unnoticed, as it undoubtedly does in a majority of 

 cases. If, however, the blood corpuscles be counted from time to 

 time a gradually diminishing number will be found, and after several 

 weeks only about one-fifth or one-sixth of the normal number are 

 present. It is, indeed, surprising how little impression upon the ani- 

 mal this very impoverished condition of the blood appeal's to make. 

 It is probable, however, that if two animals kept under the same con- 

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