Because the height or 'frame' of cattle of a given age is closely related to maturity type, the information can be used to categorise or classify a live animal, based on its growing and fattening pattern.
Large-framed and small-framed cattle grow at their quickest up until they reach physiological maturity (the stage of growth when fattening begins).
Comparative growth and weight gain of large-framed and small-framed cattle
Figure 1. Comparative growth and weight gain
of large-framed and small-framed cattle
The smaller framed cattle reach that point at an earlier age and at a lighter weight than do large-framed cattle. As the smaller framed cattle slow down in growth and begin to fatten, the larger framed cattle continue growing for a while before they begin to fatten.
At any given weight, large-framed cattle will be younger and a little leaner than their small-framed counterparts. At the same age they will be heavier but have similar fat depth as that of the small-framed cattle (see Figure 1).
Therefore, you can change the 'market weight to fatness' relationship of the cattle you produce by using bulls of different frame types. For example, producers who find that their sale cattle get too fat before they reach the optimum weight can 'stretch out' and 'trim up' future progeny by using large-framed bulls, that is, later maturing types