Studies on the Effects of a Bovine Blindness-Producing Ration upon Rabbits

Abstract

Experiments using a diet which caused optic foramen stenosis in calves failed to produce stenosis in the rabbit. The ration did produce a syndrome in the rabbit otherwise strikingly similar to that produced in calves. The effects upon growth, equilibrium, and the eye resembled the syndrome which produced stenosis of the optic foramen in calves. The development of this syndrome could be obviated by feeding adequate quantities of carotene or vitamin A. Fifty micrograms of carotene per kilogram of body weight afforded protection and the maintenance of health. Wesson oil, aerated cod liver oil, or a flavin concentrate were without the preventive or remedial effect. The remedial dose of carotene was distinctly above the preventive level of 50 micrograms per kilogram of body weight. Small doses, 30 to 70 micrograms per kilogram of body weight, were without remedial effect but if the dosage were increased from six to twenty times, recovery took place. One hundred per cent mortality was experienced unless a source of vitamin A was added. These data indicate that an adequate source of vitamin A was the primary deficiency of this ration and that sub-minimal amounts of vitamin A may produce various physiological reactions which are the results of both primary and secondary tissue responses.