I usually find they do better the second year, there are some exceptions.. I had a heifer last year that raised a phenomenal steer, this year her steer was a bit smaller but still a very nice animal... I think now that she's grown up she'll be consistently a good producer. Full sister to this cow was a heifer this year that raised a dink of a heifer.. I'm not sure everything was right in the digestive department on the calf, but the cow has grown a tremendous amount this year, so her second year will be her test. I have another full sister to the two of them that will have her first calf this spring, she looks like she's going to do very well, she's bossy enough to get food, and she's a big girl too.
I found if they raise too big a calf the first year it'll pull them down for the second, unless you'd wean particularly early perhaps. I did wean early this year, and I'm hoping to reap some rewards from it next year.. I'll also once again feed the young cows seperately to make sure they get their fair share of food and are in good condition.