Expected Versus Realized Progeny Differences for Various Beef Cattle Traits1

Studies were summarized that compared expected with realized progeny differences for birth weight (BBW), weaning weight (WBW), yearling weight (YBW), marbling (MAB), hot carcass weight (CWT), subcutaneous fat (FAT), longissimus muscle area (LEA), percent lean yield (%LY), milk (MLK), total maternal (MAT = 1/2 WBW EPD + MLK EPD) and scrotal circumference (SC). Realized progeny differences agreed well with expected progeny differences (EPD) for BBW and WBW, but for YBW, realized tended to be greater than EPD especially when YBW was the primary sire selection criteria. Relative to sires with low EPD for MAB, CWT, FAT, LEA, and %LY, sires with high EPD sired progeny with higher MAB scores and greater CWT, FAT, LEA and %LY. Also, relative to sires with low EPD for MLK and MAT, sires with high EPD sired daughters that produced more MLK and weaned heavier calves. Lastly, relative to sires with low SC EPD, sires with high SC EPD sired daughters that reached puberty earlier but subsequent daughter pregnancy rates were similar for high and low SC EPD sire groups.