In normal bones, the fluorine content varies greatly and may reach a level of 1,200 
Pepem. Or more on a fat-free dry basis. The bones of animals exhibiting a fluoride content 
of more than 4,500 p.p.m. may occur in bones that show lesions of fluorosis (Binns, 
1956). The bones of animals showing clinical symptoms contain over 5,000 p.p.m. of 
fluorine and values as high as 20,000 p.p.m. are frequently found (Garner, 1957). Urine 
values are to be used in conjunction with other data and several samples are best for 
diagnostic significance (Hobbs, et al., 1954). Levels in the range of 10 to 20 p.p.m. indi- 
cate excessive fluorine ingestion and/or bone storage which are not sufficient to cause 
damage to the animal. The finding of urinary fluorine levels above 20 p.p.m. indicates 
excessive ingestion, which could cause interference with normal body function (A.C.V.T., 
1960). During the long period of feedings when the animal shows no clinical symptoms 
the fluorine is mostly being deposited inthe skeleton. When fluorine is no longer mobilized 
the animal adapts itself to more efficient excretion in the urine. 
Nitrogen trichloride (Agene) has been used as a bleaching agent in the production of 
white flour from wheat. Because of its toxic properties in dogs, its use in the United 
States was made illegal about 1949 and in Great Britain in 1956. 
Research showed that wheat flour ‘‘improved’’ with nitrogentrichloride produced the 
same symptoms in dogs (Mellanby, 1946). The toxic substances produced by nitrogen 
trichloride in flour was isolated from agenized zein (Bentley, et al., 1949), and inde- 
pendently from treated wheat flour (Campbell, etal., 1951). It is reported to be methionine 
sulphoximine, which interferes with glutamic ¢ acid metabolism in brain tissue (Pace and 
McDermott, 1952). Degenerative changes in the cerebral cortex and cerebellum with the 
nerve cells showing necrosis, shrinking, distortion, loss of substance, and eventual dis- 
appearance were described in dogs poisoned with agenized flour (Lewey, 1950). Nontoxic 
bleaching agents, particularly chlorine dioxide, have now largely replaced nitrogen 
trichloride. 
One of the big problems with some livestock feeds has been the chronic toxicity of 
cottonseed cakes and meals from solvent extractions of some cottonseed. There is a 
specific toxic substance, gossypol, present in the pigment glands of cottonseed (Withers 
and Carruth, 1916). In methods of commercial extraction, most of the toxic gossypol is 
changed into bound gossypol which is much less poisonous. Cottonseed cakes and meals 
once varied considerably in their chronic toxicity, depending upon the method used for 
extracting the oil, the solvent used, and the variety of the seed. Symptoms may not be 
seen for some time after feeding. At low dietary levels, there was a loss of appetite and 
inhibition of growth. At higher levels, cattle, calves, and pigs manifest gastroenteritis, 
listlessness, and difficult breathing, followed later by convulsions and death (Garner, 
1957). 
Industry endeavors to keep the gossypol at low 0.02 to 0.04 percent. Because of 
variations in temperature with the hydraulic-press and of undesirable solvent in other 
processes, this amount may be greatly exceeded (Smithand Jones, 1957). Swine are more 
susceptible to poisoning from the toxic meal than other species. Symptoms commonly 
develop after pigs have been fed excessive amounts from 1 to 3 months. The lesions in 
swine are ‘‘white muscles,’ liver necrosis, edema, and cardiac changes (Smith, 1957). 
Chronic toxicity for gossypol exists even for adult cows. There are reports giving the 
usual expected variations in susceptibility of individuals, breeds, and species including 
adult cattle, calves, swine, sheep, dogs, and poultry (Leighton, et al., 1953). There are 
animals dying daily in the country that are being fed cottonseed meal, which show the 
same symptoms and lesions as have been provedas being produced by gossypol poisoning 
from these products. Laboratory findings are negative for those bacterial, viral, and 
chemical agents for which there are any diagnostic tests available. 
The ARS well aware of the gossypol toxicity through their Southern Utilization Re- 
search and Development Division has conducted and contracted research on solving this 
problem. They developed a method by which nontoxic cottonseed meal can be commer- 
cially produced. The Animal Husbandry Division, ARS, fed growing pigs for 16 weeks on 
such feeds containing only 0.012, 0.018, and 0.024 percent of the free form of gossypol 
96 
