2 MISC. PUB. 882, U.S. DEPT. OF AGRICULTURE 
poisonous or poisonous only under some circumstances, are of minor 
importance; still others are merely suspected of being poisonous. Of 
those included in this study, 48 species are reported in detail. The 
toxicity of the plants, except those that are generally known to be 
toxic and are well documented, was determined by feeding trials 
which were a modification of the standard chick-feeding test (49). 
These trials were made through the cooperation of the Federal Ex- 
periment Station, Mayaguez, P.R.* Results of the feeding trials were 
compared with information in the literature. 
Most of the plants discussed in detail have poisoned animals in the 
Virgin Islands, other Caribbean islands, the continental United 
States, and other parts of the world. Livestock losses due to plant 
poisoning include not only actual deaths but also losses through fail- 
ure to reproduce or gain. This bulletin discusses both types of 
poisoning. 
In the Virgin Islands, animals that are tied out are much more 
hable to poisoning than those that are loose. Free ranging animals 
are in greatest danger from toxic plants in pastures, less so from 
ornamentals, and least from poisonous plants in silage or green cut 
feed. The latter feed is becoming increasingly popular, particularly 
among dairy farmers. Hay is not made or used at present, but should 
it be in the future, care should be taken not to include known toxic 
plants. Although a farmer may faithfully practice preventative 
measures in livestock management and may control his poisonous 
plants, it is impossible to escape entirely some danger from them. 
LOSSES FROM OTHER CAUSES 
Poisonous plants are not the only cause of losses and sickness in 
livestock, and losses from other causes may be confused with those 
caused by plant poisoning. Chief among these are nutritional dis- 
orders, bloat, infectious diseases, impactions, and poison in feeds or 
water and from such sources as paints, petroleum products, insecti- 
cides, and herbicides. 
Although some instances of poisoning resulting from use of the 
common herbicides 2,4-D and 2,4,5-T have been reported, these chem1- 
cals are harmless to farm animals under all ordinary conditions (32). 
Losses due to farm animals consuming excessive amounts of salt 
have been reported in cattle, swine, sheep, and poultry. Sheep and 
swine are most frequently affected under field conditions. In St. 
Croix, arsenic (usually obtained by livestock drinking from cattle 
dips or surrounding puddles) has caused a number of deaths. Moldy 
or spoiled feed is sometimes responsible for livestock poisoning. The 
gossypol in cottonseed and cottonseed products may also cause poison- 
ing. (See Cotton.) 
Instances of livestock poisoning have been traced to organic poisons 
in water supplies such as might result from the decomposition of dead 
fish, or of dead livestock, in farm ponds. Although the probability 
of losses from such contaminated water in the Virgin Islands is rather 
low, dead animals should always be removed immediately from any 
water supply used by livestock. In investigating cases of livestock 
poisoning, all possible sources of poison should be checked. 
* Morris, M. P., and WrinTERS, H. F. QUARTERLY REPORT, FEDERAL EXPERIMENT 
STATION (MAYAGUEZ) PUERTO RICO. Jan—Mar., and Apr.—June, 1954. [Unpub- 
lished. ] 
