Heifers that conceive early as yearlings during their first breeding season appear to be “programmed” for productive lives. While fetal programming is a hot topic of late, Whittier says Montana researchers, using data gathered in the 1950s and 1960s and published in 1973, used that term when talking about heifer development. In that research, heifers prepared for early calving by nutrition and selection went on to be productive cows.
 

Early-born calves perform better than later-born calves.“The calving group, meaning they were calved in the first 21 days, the second 21 days, or late – the third 21 days or later – had a highly significant effect on performance from birth to weaning,” Whittier says, referring to the Montana study. That’s largely due to age – early calves are older, and therefore heavier than later-born calves at weaning.
 

Heterosis expressed in reproductive traits is real. The Montana research, as well as earlier work at the U.S. Meat Animal Research Center, clearly documents the positive effect of heterosis on reproduction, Whittier says. So while it’s not a new idea, it’s one that certainly deserves careful consideration.
 

Heifers born early in relation to herdmates have an increased likelihood that they will conceive early in their first breeding season. What’s more, that carries through to their second calf, which is critical in a heifer’s ability to earn a place in the cowherd. That’s because a heifer that calves early has a longer postpartum interval and is better able to start cycling again.
 

Heifers born to early-calving cows tend to have early calves themselves. Not only are heifers born early in the calving season set up for productive lives, but their female offspring also tend to calve early as well, Whittier says. “Thus, there’s a generational advantage for early-calvers.”
 

Steer progeny from early-calving cows produce higher value carcasses than late-calving cows. Citing Nebraska research published in 2012, Whittier says the data show that steer calves born earlier in the calving season not only had heavier weaning weights, but heavier hot carcass weights and greater marbling scores.
 

Yearling heifers that respond to estrus synchronization and conceive early to artificial insemination (AI) produce greater lifetime revenue than heifers that conceive to natural service. With advances in estrus cycle management, it is common, especially in heifers, for a high percentage of synchronized females to be in estrus on the first day of the breeding season, Whittier says. That has a lot of advantages.