Submitted to: Midwestern Section of the American Society of Animal Science
Publication Type: Other
Publication Acceptance Date: 2/1/2003
Publication Date: 7/1/2003
Citation: Cundiff, L.V., Wheeler, T.L., Shackelford, S.D., Koohmaraie, M. 2004. Feed efficiency of F1 cross steers by British and Continental European sire breeds [abstract]. Midwestern Section of the American Society of Animal Science 82(2):38. Interpretive Summary: No interpretive summary required.
Technical Abstract: The objective was to characterize F1 cross steers for efficiency of post weaning live weight gain (g/Mcal ME) in time (TIME = 0 to 187 d) and weight (WT = 340 to 590kg) intervals or from the starting date (day 0) to a marbling (MARB = small degree of marbling), fat thickness (FTH = 1.1 cm), fat trim (FTR = 24.8% fat trim), or weight of retail product (RP = 225 kg) endpoint. Data were obtained on 649 steers born in 1999 and 2000 resulting from matings of Hereford, Angus, and composite MARC III (1/4 each Angus, Hereford, Red Poll, and Pinzgauer) cows to sires of three British breeds (B: Hereford, 21 sires; Angus, 22; and Red Angus, 21) and four Continental European breeds (C: Simmental, 20; Gelbvieh, 23; Limousin, 20; and Charolais, 22). The steers were weaned in mid-October at a mean age of 202 d. Following a 30 d conditioning period, the steers were assigned to replicated pens (2 pens per sire breed per yr). Feed consumption was recorded daily. Steers were fed a growing diet (2.62 Mcal ME/kg DM) until early February (about 320 kg) and a finishing diet (3.05 Mcal ME/kg DM) until slaughter. Steers were slaughtered in 5 groups spanning 43 d the first yr and 4 groups spanning 53 d the second yr. Retail product (boneless - totally trimmed, .0 cm outside fat) and fat trim were estimated using wholesale rib dissection prediction equations. Regression of MARB, FTH, FTR and RP on days on feed was used to estimate days required for each sire breed to reach each endpoint. Quadratic regression of pen mean weights and cumulative ME on days fed were used to estimate pen mean efficiencies for each interval and endpoint. Effects of sire breed were not significant for efficiency in TIME or WT constant intervals. Steers with B sires were more efficient (P<.01) than those with C sires to MARB (B = 59.9, C = 54.7, g/Mcal), FTH (B = 59.3, C = 54.5), and FTR (B = 59.6, C = 54.7) endpoints. However to the RP endpoint, steers with C sires (58.3) were more efficient (P<.01) than those with B sires (54.9).