PARASITIC DISEASES OF CATTLE IN PUERTO KICO •> 
GENERAL PARASITE CONTROL MEASURES 
DISPOSAL OF MANURE 
A> manure is the direct or indirect source of most of the common 
parasites, its proper disposal is an important factor in control. 
Fresh manure or unrotted manure from an open pile, from infested 
animals, should not be spread on pastures or on land which is to be 
used for growing forage, especially the smaller grasses, unless it is 
plowed under. Plowing buries the eggs and larvae and apparently 
they do not get back to the surface in sufficient numbers to cause 
serious trouble. Horse manure may be spread on pastures or grass 
fields to be used by cattle, and vice versa. With 1 or 2 minor excep- 
tions the internal parasites of horses are not transmissible to cattle, 
and horses are not susceptible to those of cattle. 
A dangerous practice which is equivalent to feeding the animals 
from the top of a manure pile is sometimes followed. The forage is 
fed from piles on the ground. The left-over grass accumulates and 
becomes mixed with the manure. These piles retain moisture and 
provide favorable conditions for the larval forms of parasites. As 
soon as a light rain or heavy dew occurs the larvae may come to the 
surface and contaminate the fresh grass. The forage should always 
be fed from tight mangers and any left over should be disposed of 
with the manure. 
ROI.E OF FORAGE GRASSES IN PARASITE CONTROL 
The roughage for livestock in Puerto Rico other than pasturage 
consists of soiling, usually a forage grass cut and fed in a fresh, 
green condition. Dried or stored roughages such, as hay and silage, 
which carry very little if any parasitic infestation, are not used to 
any extent. Therefore the selection of the soiling grass is very 
important from a parasitological viewpoint. 
The giant or rank-growing grasses such as Guatemala, elephant, 
and sugarcane carry very little parasitic infestation in comparison 
with the smaller grasses such as malojillo (Para grass) or guinea 
grass or other similar grasses even though fresh contaminated 
manure is spread on the fields in which the larger grasses are grown. 
As the stalks of these giant grasses grow upright and are compar- 
atively few in number the infective eggs and larvae of parasites are 
less likely to be present on them. 
Malojillo grass is more apt to carry these infective stages than 
other grasses because it grows in more direct contact with the ground 
and thrives only on marshy land very favorable for the development 
and perpetuation of parasites. Malojillo fields cannot be protected 
from contamination by the usual measures because infective material 
may be washed onto them with every fall of rain. Malojillo grass 
should be regarded as being unsafe to feed to calves. The cleaner 
giant grasses may be fed to calves, goats, and horses, but malojillo 
grass should be fed only to older cattle. 
Guinea grass, or other small grasses grown on fields which have 
not been fertilized with fresh cow manure and where there is no 
danger of contamination by drainage from adjacent land on which 
infested animals are maintained, may be fed to calves without danger 
of infesting them with parasites. 
