Germplasm evaluation in beef cattle-cycle IV: birth and weaning traits

Area of Science:

• Animal Science
• Genetics
• Reproductive Biology

Background:

• The Germplasm Evaluation (GPE) Program at the U.S. Meat Animal Research Center evaluates genetic impacts on beef cattle production.
• Cycle IV of the GPE Program focused on F1 crosses using diverse sire breeds with Angus and Hereford dams.

Purpose of the Study:

• To assess the effects of different sire breeds on key reproductive and growth performance traits in beef cattle.
• To compare the efficacy of various sire breeds in improving calving ease and calf weaning weights.

Main Methods:

• Evaluated 2,597 calves from F1 crosses involving 11 sire breeds (Angus, Hereford, Charolais, Gelbvieh, Pinzgauer, Shorthorn, Galloway, Longhorn, Nellore, Piedmontese, Salers) and Angus/Hereford dams.
• Measured gestation length, unassisted calving percentage, perinatal mortality, calf survival to weaning, birth weight, and 200-day weaning weight.
• Included reference and 1980s-era Hereford and Angus sires for historical comparison.

Main Results:

• Sire breed significantly influenced gestation length, calving ease, birth weight, and 200-day weaning weight.
• Nellore sires resulted in longer gestation, while Charolais, Galloway, Longhorn, Piedmontese, and Salers were shorter than Hereford-Angus and Shorthorn.
• Charolais, Nellore, Salers, and Shorthorn sires produced the heaviest weaning weights, with significant differences observed.

Conclusions:

• Sire breed selection is critical for optimizing beef cattle production traits, including calving ease and growth performance.
• Breed differences in gestation length and birth weight have implications for calving management and perinatal survival.
• Specific sire breeds offer distinct advantages for weaning weight, highlighting opportunities for genetic improvement programs.