However, data presented by Pickworth, Loerch, Kopec, Schwartz, and Fluharty (2012) and the results
from the present study (Table 1) indicate that basal feedlot diets can contain from 500 to 2200 IU of VA/kg from pro-vitamin A carotenoids, which is enough to meet the animals' VA requirement. As such, many recent VA studies in beef cattle have not observed performance differences based on concentrations of vitamin A supplementation