164 SWINE DISEASES 



her by catching her small pigs and, while they were 

 squealing, carried them around the pen. The best 

 method to pursue in cases of viciousness in swine is to 

 prepare them for slaughter and market them as soon as 

 possible. 



Sunstroke and Heat Stroke 



It may be possible to differentiate between sunstroke 

 and heatstroke in man, and possibly also in horses, but 

 such a distinction is scarcely warranted in swine. 



Sunstroke is claimed to be due to the action upon the 

 nerve cells of actinic rays of the sun, and heat stroke to 

 a disturbed equilibrium of heat production and heat dis- 

 sipation. The two conditions frequently occur simul- 

 taneously in the same animal. 



Etiology. These conditions are the result of direct 

 exposure to sunshine and excessive heat. Driving swine 

 in droves is occasionally accompanied by cases of heat 

 stroke, and this may also be observed in carload lots in 

 which the swine are crowded and the shipment made in 

 extremely hot weather. The same condition arises in 

 swine that are hauled in wagons, if proper precautions 

 are not taken. Lack of proper shade predisposes the 

 swine to sunstroke and to heat stroke. 



Lesions. There are no gross lesions that characterize 

 either sunstroke or heatstroke, except a parboiled appear- 

 ance of parenchymatous tissues. Microscopically, the 

 nerve cells are found to contain coagula, and there may 

 be cloudy swelling of all parenchymatous tissues. 



Symptoms. Uncertain gait, dullness, depression, 

 increased respiration, and anxious expression are the 

 principal symptoms observed in the early stages of these 

 conditions. The temperature may be very high. Muscu- 

 lar tremors, falling to the ground, and convulsions are the 

 final symptoms. The course of the disease is short. 

 In some instances the animal succumbs within a few 

 minutes after the onset; in other cases the animal may 

 live for from one to three days, and in rare instances 

 may recover. 



