Relationship between Plasma Vitamin A and Liver Vitamin A in Calves Fed a Vitamin A Depletion Ration and Calves Fed Minimum Levels of Vitamin A or Carotene

Abstract

Summary Data on blood plasma vitamin A and liver vitamin A concentrations from 58 Guernsey and Holstein calves fed a vitamin A depletion ration and whose average age and body weight was 128±19 days and 263±72lb., respectively, and from 39 Holstein calves fed minimum levels of vitamin A or carotene and whose average age and body weight were, respectively, 200±9 days and 436±48lb. were explored as to possible relationship. When plasma vitamin A and liver vitamin A were expressed as logarithms, a positive linear relationship was found between these two variables. In calves fed the vitamin A depletion ration, the blood plasma vitamin A level was found to be less at a given concentration of vitamin A in the liver than in the calves fed minimum levels of vitamin A or carotene. Positive linear relationships of log liver vitamin A concentration on log plasma vitamin A concentration were derived for purposes of estimating liver stores of vitamin A in calves fed the vitamin A depletion ration and in calves fed minimum levels of vitamin A or carotene. These had applicable limits for prediction of approximately 3.6 and 25.8γ of vitamin A per 100ml. of blood plasma.