226 Common Diseases of the Horse 



The eggs of the female pass out with the dung, and in pastures 

 are, therefore, scattered all over the field in immense numbers. 

 The eggs first hatch into a small worm, which feeds in the dung, 

 and in time casts its skin (moults), and then develops a thick coat 

 and becomes dormant. In this condition it can live for months, 

 until swallowed by a horse, when it moults again, pierces the bowel 

 lining, and becomes a full-grown worm. Now the small forms 

 that pierce the bowel often get into the blood stream and become 

 arrested anywhere, but usually at the junctions of important large 

 arteries to the bowels. Here they develop and produce great 

 bulging of the vessels, which may even cause them to burst. In 

 any case the vessels are blocked up by the growths produced, and 

 pieces of material get loose and thus block up other small arteries. 

 In this way colic in old horses is sometimes caused. Further 

 remarks will be made under the next species, as the symptoms, 

 treatment, and prevention are similar. 



Red or Wire W^orms 



There are also several species of these. Some are blood-stained 

 and others are white. They vary in length from ^ to about | in. 

 Some are as thick as darning wool, but others only the thickness 

 of ordinary cotton. The life-history is somewhat similar to the 

 preceding species. There is, however, no tendency to gain the 

 blood stream. These worms are very common, and their ravages 

 are great. They are most injurious to young animals, and many 

 breeders have had to give up rearing foals on certain farms. 

 Thoroughbred studs have been similarly affected. The worm is 

 found in the large intestine, and the little abscess it produces 

 allows the entrance of microbes. The worms themselves produce 

 a poison which affects the blood. 



The symptoms are as follows: Young horses are first noticed 

 not to be doing well, then the coat is not shed at the right time; 

 there is loss of flesh, increasing weakness, sometimes the stifles are put 

 out temporarily ; there may be diarrhoea, the eyes appear white, and 

 there are all the signs of want of blood (anaemia). An examination 

 of the dung will reveal the presence of the small red worms. When 

 this state of affairs has been reached, and particularly if it has hap- 

 pened in previous years, the affected pastures must be grazed by 

 sheep or cattle, as they are not affected by these worms. It may 

 be limed, or better still, ploughed and put under a complete rota- 

 tion of crops before being again grazed by horses. Actual treat- 

 ment is not at all satisfactory. It will easily be appreciated that as 



