4 
BULLETIN 3 8, PUERTO RICO EXPERIMENT STATION 
or destroying the infective material. In the dry sections or where 
the soils . are sandy or porous the drainage requirements are less 
exact but in like manner the yards must be kept free of all vegetation. 
The College of Agriculture at Mayaguez has successfully used 
bare lots with a herd of purebred hogs over a period of several years 
and very little attention has been paid to such sanitary measures as 
cleaning up manure accumulations and rotation of yards. Examina- 
tions have shown that these animals are remarkably free of internal 
parasites. Varying somewhat in detail, other farmers are using dry, 
bare lots with very little, if any, trouble from parasites. Often this 
method has developed on individual premises more by accident than 
design owing to the absence of shade trees and the destruction of 
the vegetation by the animals themselves. 
Yards should not be situated so that one can drain into another. 
In all cases, the rotation of yards or pastures is very desirable. Each 
year or oftener a fresh lot should be occupied and, unless plowed, 
at least 1 year should elapse between successive occupations. Other 
aids in disinfection are plowing two or more times a year and fre- 
quent applications of air-slaked lime to the yards and feeding places. 
Hogs should not be confined in small, covered pens unless the floors 
are of tight construction, preferably of concrete, and are kept in a 
dry, sanitary condition and free of dust. As parasites among un- 
confined pigs which range over a wide territory are less subject to 
control by preventive measures, these animals should be confined in 
sanitary yards or pastures. Cultivated pastures should receive more 
attention, as several valuable crops for hogs can be grown and 
pastures can be used during the entire year. 
BARE-LOT METHOD OF RAISING PIGS 
A special farrowing yard enclosing about 500 square feet should 
be provided. This yard should be used for only one purpose and by 
one sow with litter at one time. It must be located on a well- 
drained, unshaded or properly shaded area. All growing vegetation 
should be trimmed close to the ground and removed or plowed 
under, and the surface should be kept in this condition during occu- 
pancy. A pen consisting of a concrete floor at least 6 by 6 feet in 
size, with a roof set on posts, should be constructed in or opening 
into the yard. Except for woven wire as a barrier the sides of 
this pen should be open. The sanitary features of the yard can 
be improved by providing at one end a separate enclosure or feeding 
floor for the sow and at the other end a creep with a self-feeder 
for the pigs. The pigs should be prevented from entering the feed- 
ing floor. 
If previously occupied, the floor of the pen should be scrubbed and 
disinfected with a 3-percent solution of compound cresol (U. S. P.). 
A few days before farrowing, the sow, if encrusted with mud and 
tilth, should be scrubbed with a brush, using soap and warm water, 
on the sides, udder, and entire lower portion of the body, and then 
placed in the farrowing yard. The bedding must be watched care- 
fully and changed when it becomes foul or wet. The manure and 
all other accumulations in the yard should be frequently and thor- 
oughly removed and properly disposed of. After weaning, the pigs 
should be separated from all other hogs and placed in a fresh. 
