A recent symposium addressed current thinking on development of beef heifers. Texas A&M animal scientist Stephen Hammack, PhD, provides this summary of key points.
• Heifers developed more rapidly before typical weaning age — especially early-weaned and on high-concentrate diets — reach puberty earlier, but this may not be economical.
• Developing heifers to 60 to 65 percent of expected mature weight for breeding at 14 to 15 months, as has generally been recommended, does not appear to be necessary for good levels of reproduction.
• Reduced nutrition for a period immediately post-weaning does not adversely affect reproduction and is more economical, if heifers receive adequate nutrition later for compensatory gain to reach 50 to 57 percent of expected mature weight by breeding and have adequate nutrition during breeding.
• Compared to being developed to 60 to 65 percent of mature weight, heifers developed to 50 to 57 percent of mature weight weigh less at breeding, gain more during breeding, have similar conception rates, calve as early, weigh the same at calving, and have higher lifetime retention rates and greater longevity only if nutrition is adequate after development.
• Heifers with low residual feed intake, meaning high feed efficiency, tend to be leaner, resulting in later puberty and time of conception, but the same was not found in heifers of high residual daily gain, which is a different measure of feed efficiency.
• Heifers that are never nutritionally restricted up to breeding may subsequently not be as adapted to typical range or pasture conditions where most beef cow herds are maintained.