ABSTRACT
Optimum reproduction is probably the major determinate of efficiency in beef production because of the large overhead that maintenance of the brood cow represents in the total feed required to produce beef. Beef cows have only one real function -- to produce calves. Cow size has received a lot of rhetoric since the exotic breeds were introduced into the US Large-sized cows obviously require more feed than small-sized cows. Four critical feeding periods in the female's life cycle that relate to good reproductive performance in beef cattle are when she is a heifer prior to breeding, bred heifer, lactating heifer, and cow. Profit potential is of great importance when related to cow size and amount of nutrition larger-sized heifers require to reach puberty. Relative to heifers, nutrient requirements for cows are lower and represent the best place to utilize low quality and inexpensive feed sources.
