According to University of Arkansas Division of Agriculture Cooperative Extension Service, the goal of all beef production systems should be to meet nutrient needs of all classes of animals at a level which optimizes performance at the lowest cost.

Properly identifying energy and protein needs of a particular class of livestock is the first step. For example, requirements of a dry cow are considerably less than those of a nursing cow. Likewise, those of growing replacement heifers are different from those of a bull in the "off season."

Since the requirements vary so much, it only makes good "cents" to group cattle according to nutrient needs.

Any extra time you spend separating cattle during the hay-feeding season will more than offset economic benefits realized next spring.

Source: Baxter Bulletin