" I was always told not to save a heifer out of a heifer. But that's just what I was taught"
JMJ,
That's an old saw with not much meat behind it.
Yeah, a first-calf heifer's calf will generally give up 60+ lbs weaning weight to a calf by the same sire, out of a similar 4-5 yr old cow... as a result, many don't 'make the cut', when folks are selecting replacements based solely on size/weight... but no reason at all that that heifer's daughter can't/won't grow off to make just as good a cow.
I've had some good cows come out of first-calf heifers through the years, but I'm at a point that I can't and don't want to keep every heifer calf born here.... I let the retained first-timers go to a young 'cleanup' bull, for the most part,and if they mother that baby, do a decent job raising it, and breed back, I look at that first calf as a 'coupon' - mostly redeemed at the salebarn - giving her a chance to stay and PROVE herself with the next one.