Short story, weightlifter practices lifting a calf, then a baby elephant.

[Brian]

Short story, read in the late 80s. A farm boy wants to be a bodybuilder and starts lifting a baby calf every day, theorizing that it will put on a nominal amount of weight daily and eventually he'll be able to lift it as a full grown cow. When the circus passes through town, he joins it, deciding to do the same thing with a baby elephant. One day he misplaces his glasses and attempts to lift the mother elephant and dies of a heart attack. As he passes, he comments on how a baby whale couldn't weigh too much...