480 DISEASES OF SWINE 



In this case the final outcome was not as favorable as we have 

 seen in a number of the other herds where the serum or serum and 

 virus were used. However, this can, in large measure, be explained 

 in this herd from the fact that the disease was apparently well 

 started in the herd before the serum was first made use of. If 

 the injection had been given in this herd a few days earlier there 

 might have been a much different history to record. Even as it 

 was, the percentage of deaths was low as compared with what it 

 would usually have been without the use of this method of treat- 

 ment. 



In this herd it will be noted that the disease was apparently 

 of a quite severe type, and the animals appear to have been quite 

 susceptible to the action of the disease. This was, no doubt, in 

 part due to the fact that this was a pure-bred herd, and also to the 

 fact that the gilts, in which the disease made its most severe inroads, 

 were exceedingly fat. It will be remembered that in discussing 

 the predisposing factors in the production of hog-cholera it was 

 stated that pure-bred animals were usually of a more frail con- 

 stitution and more susceptible to the disease. This is in large part 

 due to the overcare which these pure-bred herds receive. The 

 animals are simply pampered and force fed until their powers of 

 resistance against disease are very much lowered. As a result, 

 when cholera or any other severe disease strikes them they are in 

 poor condition to resist, and fall easy victims to the attack. 



Overfat animals also are very liable to fall early victims in an 

 outbreak of cholera. When hogs are force fed and fattened very 

 rapidly there is a weakening of the heart and muscles, due to an 

 overdeposit of fat in their structure, and, as a result, the animal 

 becomes so weakened as to be unable to fight vigorously against an 

 attack of any disease. These are all-important elements in figur- 

 ing the odds for and against recovery in a given case of cholera, 

 and must all be taken into consideration in passing judgment upon 

 the effects obtained by treatment by serum or any other method. 



In the case of the boars of this herd, which were kept in a 

 separate lot and were not directly exposed to contact with the sick 

 animals, the loss was very slight. The disease did, however, ap- 

 parently reach this herd, but the loss was kept down by the effects 

 of the treatment given. The results in this herd should serve to 



