2 CIRCULAR 14 8, U. S. DEPARTMENT OF AGRICULTURE 



progressing chain of symptoms which the owner may entirely over- 

 look or confuse with other conditions. The general symptoms of 

 worm infestation in the horse are unthriftiness. weakness, emacia- 

 tion, tuckecl-up flanks, distended abdomen, rough coat, whitening or 

 bleaching of the mucous membranes (noticed particularly in the 

 mucous lining of the eyelids and mouth), and in some cases frequent 

 colics and diarrhea. The appetite usually remains good and the ani- 

 mal shows no rise in temperature. Heavily parasitized animals tire 

 quickly and are frequently unable to stand heavy work. 



Parasites are particularly damaging to young, growing animals. 

 They attack the foal when it should be making its best growth and 

 produce stunting and lack of development. A considerable part of 

 this damage is a result, no doubt, of the wanderings of the larval 

 worms through various parts of the body of the host before they 

 reach their preferred location where they develop to maturity. 



"While the death rate from parasitic infestation is not high, never- 

 theless these internal pests cause considerable damage. The loss is 

 represented largely by the poor development and stunting of foals, 

 inability of heavily parasitized horses to do a normal amount of 

 work, added costs of feed and maintenance, and loss of working time 

 from verminous colics. The aggregate loss resulting from these con- 

 ditions is sufficient to warrant the attention of horse owners to the 

 subject of parasite control. 



GENERAL CONTROL MEASURES 



Most parasites of livestock owe their perpetuation to the fact that 

 domestic animals often take their food from the same places they 

 deposit their fecal matter. The eggs of parasites are passed by 

 horses with the manure in stables and on pastures and then go 

 through various stages of development, after which either the eggs 

 or the larval worms reach the interior of the horse with the food and 

 drinking water. Prevention must be directed toward breaking this 

 cycle. Stables and paddocks should be kept in a sanitary condition 

 by the frequent removal of manure. Concrete standings, although 

 objected to by some horsemen, have the advantage of being easily 

 cleaned and provide a relatively unfavorable medium for the de- 

 velopment of parasites. If wooden standings are used, the timber 

 should be sound. Rotten, moisture-soaked floors are difficult to keep 

 clean, and they provide a favorable medium for the development 

 of parasites. If standings of earth are used, it is advisable to re- 

 move the top layer of soil down to 10 or 12 inches once or twice a 

 year and replace it with clean, uncontaminated soil. 



Horses should be fed grain from feed boxes and hay from racks 

 which are sufficiently high above the ground or the floor of the stall 

 to prevent contamination of the feed with manure. Watering 

 troughs should be so constructed as to prevent similar contamination 

 of the drinking water. Horses should not be forced to obtain drink- 

 ing water from pasture or barnyard pools. In general, low, wet 

 pastures are more favorable for the propagation of parasites than 

 are high, well-drained areas. Animals grazed on heavily stocked, 

 permanent pastures have greater opportunity for picking up para- 

 site eggs and larva? than those changed frequently from one pasture 

 to another. For this reason pastures should be changed as often as 



