DISEASES OF ANIMALS 



111 



body brown with three rows of black 

 spots. Prom June to October the flies 

 lay their eggs on the hair of the horse 

 in a position where the animal can reach 

 them by bitii.g or licking. The eggs are 

 thus taken into the stomach, where the 

 young maggotc hatch and attach them- 

 selves to the walls of the stomach. Here 

 they remain until they become full 

 grown, when they loosen themselves and 

 pass out of the feces. Some experi- 



Fig. 58 — NORMAL PRESENTATION OP COLT 



ments indicate that bi-sulphide of car- 

 bon administered in small doses in cap- 

 sules has a beneficial effect ir expelling 

 bots, but as a rule the administration of 

 drugs to destroy or expel these parasites 

 is quite unnecessary. Horses should he 

 thoroughly groomed in order to remove 

 or destroy the eggs and prevent their en- 

 tering the stomach. 



The screw worm fly is somewhat 

 larger than the common house fly, but 

 resembles the latter in general appear- 

 ance. The color is a metallic green, 



Fig. 59 — another normal presentation 



OF COLT 



with three black stripes on the back. The 

 eggs of the screw worm fly are laid in 

 wounds or natural openings of animals, 

 or of man, and the grubs, after hatching, 

 bore into the flesh, making deeper 

 wounds. Infested animals, if untreated, 

 may die of blood poisoning. Tar, grease 

 or fish oil on wounds will sometimes as- 

 sist in keeping the flies away. If wounds 



become infested, it is necessary to re- 

 move the maggots and treat the surface 

 with a solution of corrosive sublimate 

 or crude carbolic acid. 



DISEASES OF MULES 



As already indicated in the discussion 

 of mule raising, these animals are sub- 

 ject to the same diseases which affect 

 horses. Glanders is a very fatal dis- 

 ease of mules and spreads rapidly among 

 them. They are also subject to colic, 

 anthrax, surra, mange and various other 

 troubles. Corns are not as often ob- 

 served in mules as in horses for the rea- 

 son that the feet have a form which 

 better protects them against bruises 

 than is the case with horses. Likewise, 

 poll evil is less common in mules than 

 in horses on account of the fact that 

 they seldom throw up the head so as to 

 bruise it. The diseases to which mules 

 are susceptible may be treated in the 

 same way as with horses. 



DISEASES OF CATTLE 



The diseases to which cattle are sub- 

 ject are in some respects of more im- 

 mediate concern to man than those of 

 any other of our farm animals. This 

 is particularly true for the reason that 

 man is not only closely associated with 

 cattle, coming in physical contact with 

 them nearly every day, but also for the 

 reason that Ave use the meat and milk as 

 standard articles of food. The meat 

 may not only be infected with certain 

 bacterial and animal parasites, but may 

 also undergo changes as a direct result 

 of bacterial infection, leading to more or 

 less serious trouble in man. Moreover, 

 milk is one of the very best media in 

 which bacteria can multiply rapidly; it 

 also carries bacteria in some cases di- 

 rectly from the cow. Thus, the milk of 

 tuberculous cows, or those suffering 

 from foot and mouth disease, is a dan- 

 gerous article of food. As already in- 

 dicated, any bacteria which may gain 

 entrance to the milk after its removal 

 from the cow may also multiply and 

 render the milk dangerous for human 

 consumption. Sanitary officers are 

 therefore under heavy obligation to pro- 

 tect man against the use of infected 

 food products from cattle. 



Tuberculosis — Among the various dis- 

 eases which afflict farm animals, there 

 is none of such transcendent importance 

 as tuberculosis, either from the stand- 

 point of the losses which it causes to 



