Terminal, and buy replacements. The absolute best c ross for maximum hybrid vigor, is Brahma bull on Hereford cow. Whoever raised the F1 Brafords you get, already took advantage of that with the steers. The best 3rd cross on an F1 Braford is Angus/Brangus/Ultrablack. That gives you maximum heterosis on a 3 way cross. Sell those calves, steers and heifers both, and they are gonna top the market. Then buy replacements as you need them.Keeping replacements from that cross or terminal and buying replacements?
On the Corrientes, sell heifer and steer calves , weaning them at 6 mos. At that size and age, they will bring you as much as any other commercial black calf of the same size and age. You will only pay $300-$500 for a Corr cow. she will weigh 700# or so. She will wean a 500lb calf in 6 mos that today at the sale would have brought $1.40..$700.00. You don't want to retain these heifers. No point in it, when they can be sold at weaning for more than a cow will cost.