DISEASES OF ANIMALS 



91 



In some instances, it has an irritating 

 effect upon the kidneys and must be dis- 

 continued for this reason. 



Medicinal effect of certain feeds — 

 A large percentage of feeds exercise a 

 more or less pronounced medicinal effect 

 upon the alimentary tract in addition to 

 their nutritive property. Thus, roots, 

 as a whole, silage, alfalfa, and various 

 leguminous crops, as well as green for- 

 age in general have a slightly laxative 

 effect, which, in some cases, becomes so 

 pronounced that it must be corrected 

 by reducing the amount of laxative feeds 

 in the ration or by giving other feeds 

 with an opposite tendency to counter- 

 act the effect of the feed. Horses which 

 are accustomed to receiving timothy hay, 

 when first put on alfalfa, are often badly 

 affected in this way and perspire more 

 freely than they ordinarily do. After 

 a short period of feeding, however, the 

 disagreeable effects wear off. It is 

 highly desirable, therefore, that changes 

 of this sort in the ration be made in a 

 gradual manner so as to avoid digestive 

 disturbances or loss of appetite. 



The appetite of animals must be 

 closely watched in order to obtain the 

 best results from feeding. It is not al- 

 ways possible to determine at once what 

 is the cause of the failure of appetite. 

 As a rule, however, it indicates either 

 an excessive ration, the too long con- 

 tinuance of a forcing ration, the iise of 

 unwholesome materials, or lack of va- 

 riety. In working horses the loss of 

 appetite is not so serious a matter since 

 a change of ration and the use of pur- 

 gatives and tonics usually restore the 

 appetite. 



Any loss of weight suffered dur- 

 ing the feeding period is an exceed- 

 ingly serious matter in the case of 

 steers, sheep and hogs which are being 

 forced for market. In these animals a 

 loss of weight means not only the abso- 

 lute loss due to the original trouble, but 

 also a considerable period of delay dur- 

 ing which the animal still continues to 

 make unsatisfactory gains. Since so 

 many of our domestic animals are main- 

 tained under somewhat unnatural con- 

 ditions and since, on this account, un- 

 usual demands are made of their diges- 

 tive power, it is necessary for the farmer 

 to give strict heed to the appetite of all 

 his animals in order to prevent losses 

 which may occur from neglecting this 

 matter. A simple and almost univer- 



sally practiced method of preventing 

 loss of appetite consists in a change of 

 grain and roughage rations, and if this 

 change is made with proper regard to 

 the equivalents in feeding value of the 

 different rations, beneficial effects are 

 almost always observed and no loss oc- 

 curs as a result of the animal going off 

 feed. 



Water as a source of disease — Water 

 is commonly recognized as a source of 

 many animal diseases, but its impor- 

 tance in this connection is probably un- 

 derestimated by the majority of farm- 

 ers. Eecently, however, an increased 

 interest in the protection of the water 

 supply is being shown by the most ad- 

 vanced stockmen. Water is not only 

 capable of carrying bacterial diseases, 

 but a number of the most serious ani- 

 mal parasites are transmitted by drink- 

 ing water or by eating grass and other 

 plants which grow along the edge of in- 

 fested pools or water ways. 



The relative percentage of infection in 

 different kinds of animals from drinking 

 impure water depends partly upon the 

 amount of the water which the animal 

 consumes, but more immediately iipon 

 the quality of the water. Most bacteria 

 are gradually destroyed in running water 

 which is subject to sufficient movement 

 to cause a reasonable amount of aera- 

 tion. Nearly all pathogenic bacteria, 

 however, live for a greater or less time 

 in pure water and when once the water 

 becomes contaminated the danger of in- 

 fection, therefore, persists for several 

 days. The number of bacteria in water 

 naturally varies greatly according to the 

 sources of the water and the amount of 

 filth Avhich it carries. Thus, in a hog 

 wallow there may be as high as 2,500,000 

 bacteria per cubic centimeter of water, 

 while in well-floated cisterns and deep 

 wells properly protected the number may 

 not be more than a few hundred in the 

 same quantity of water. The number 

 of bacteria in water and the consequent 

 danger from using it depends also upon 

 the depth of soil through which the 

 water has filtered. Thus, as shown by 

 Bitting, the number of bacteria in a 

 cubic inch of surface soil may be as 

 high as 518,000, while at 1 inch below 

 the surface it is only 51,000 and at 5 

 feet only about 2,500. The number of 

 bacteria in the soil, however, will nat- 

 urally vary according to the amount of 

 rain and the severity of the storms. 



