6 The Diseases of Animals 
before receiving grain. Bulky food, or that con- 
taining a large amount of indigestible substance, 
should be fed to horses sparingly. Cattle and sheep 
are not so easily injured by it, since they have greater 
digestive capacity. Musty or dusty hay fed to horses 
is likely to produce indigestion or heaves; and it is 
often a source of much trouble to other animals. 
Moldy and wormy food is often the cause of a 
serious brain disease among horses and mules; and 
moldy ensilage sometimes poisons cattle. 
Grasses or grain often contain ergot, a parasitic 
fungus, which shows itself among the healthy grains 
as long black kernels. This fungus most frequently 
attacks rye and related wild grains. The feeding of 
this “spurred rye” to animals is likely to produce in 
them a disease called ergotism. In this disease the 
blood-vessels of the extremities contract to such an 
extent that the feet of the afflicted animals frequently 
slough off, and sometimes, also, the tails. Corn-smut, 
so far as known, does not cause disease. If fed in 
large quantities, however, it is likely to produce indi- 
gestion. 
Underfeeding is a result of insufficient food, or 
of food that is not sufficiently nutritious and diges- 
tible. As a result of underfeeding, animals fall away 
in flesh, become “hidebound,” and the coat takes on 
a harsh and lusterless appearance, which is caused by 
the absorption of fat from beneath the skin. A sim- 
ilar appearance may also be produced by disease. In 
bringing underfed animals back into condition, care 
must be taken not to overfeed. It is best to increase 
