Genetic changes in beef cow traits following selection for calving ease.

Area of Science:

• Animal Science
• Genetics
• Reproductive Biology

Background:

• Selecting for calving ease is crucial for reducing dystocia in cattle.
• Calving ease is often linked to birth weight, potentially impacting lifetime productivity.
• Genetic selection for calving ease requires evaluating long-term effects on dams and progeny.

Purpose of the Study:

• To compare lifetime productivity of cattle from lines selected for calving ease versus control lines.
• To assess the impact of calving ease genetics on dam performance, calf survival, and carcass traits.
• To identify any unfavorable effects associated with genetic selection for calving ease.

Main Methods:

• Comparison of experimental select and control calving ease lines across seven populations.
• Tracking 720 heifers from select lines and 190 from control lines through four parities.
• Evaluating birth weight, weaning weight, hip height, mature weight, calving success, calf survival, and carcass traits.

Main Results:

• Select lines had heifers with 2.6 kg lighter birth weights and shorter hip heights.
• Select lines showed greater calving success, earlier calf births with less assistance, and higher calf survival to weaning, especially in heifers.
• Steer progeny from select lines had greater fat depth, while select cows weaned more calves and stayed in the herd longer.

Conclusions:

• Genetic selection for calving ease improves dam and calf performance without significant unfavorable effects.
• Calving ease genetics positively influence calving success, calf survival, and dam longevity.
• The study demonstrates the benefits of selecting for calving ease in beef cattle production systems.