Avitaminosis A in Commercial Poultry Flocks

DURING the winter months the Maryland Livestock Sanitary Service Laboratory receives for examination numerous chicks which exhibit subnormal growth, general poor condition, and in some cases symptoms and lesions suggestive of a border-line deficiency of vitamin A. A rather large number of these chicks show no symptoms of infectious disease. It is generally taken for granted that growing chicks produced on poultry farms receive sufficient vitamin A in their diet. However, Fraps and Kemmerer (1937) and Taylor and Russell (1938) have demonstrated the unstable nature of vitamin A and its precursors, the carotenes, in various poultry feedstuffs. This work suggests the possibility that the optimum amount of vitamin A may not be present in the feed at the time chicks consume it but may have been present at the time of mixing, thus favoring the development of border-line vitamin A deficiency. Elvehjem and Neu (1932) reported that kidney degeneration occurred . . .