2 CIRCULAR 148, 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, tucked-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 
eolics and diarrhea. ‘The appetite usually remains good and the an1i- 
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 larvee than those changed frequently from one pasture 
to another. For this reason pastures should be changed as often as 
