Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 4/14/2008
Publication Date: 7/23/2008
Citation: Rolfe, K.M., Nielsen, M.K., Ferrell, C.L., Jenkins, T.G. 2008. Estimates of genetic variation for feed intake and other characteristics in growing beef cattle [abstract]. Journal of Animal Science. 86 (E-Supplement 2):546.
Technical Abstract: Calves born between 2003 and 2006 at the U.S. Meat Animal Research Center provided data for estimation of genetic and phenotypic parameters for measures of body weight and gain and feed intake during the finishing phase. At average age 278 d, cattle were started on a high-energy diet of corn, alfalfa hay, soybean meal, and supplement. They were individually fed for ~138 d in pens of 4 to 8 steers by use of Calan headgates. Cattle were fed to an average optimum end weight, but harvested in four groups per year at a commercial slaughter facility. Steers were produced by randomly mating F1-cross sires to straightbred and F1 females. Nine breeds were represented in various fractions in the steers. These were: Hereford, Angus, Simmental, Charolais, Limousin, Gelbvieh, Red Angus, Pinzgauer, and Red Poll. Fifty-nine sires produced half-sib families. A total of 820 crossbred steers were analyzed with a pedigree file of 4,051 animals. Traits analyzed were ADG, DMI, mid-period body weight (MBW), and residual feed intake (RFI; determined from DMI adjusted for MBW and ADG). Flight time (FT) was collected at least twice (separated by ~60 d) as a possible indicator trait for temperament; two sets of electronic eyes were placed 5.5 m and 10.8 m beyond a scale box where the animals were temporarily detained. REML methods were used in univariate models that accounted for the fixed effects of year, month for only FT, pen size, breed and breed heterozygosity; random effects were animal genetics, pen, permanent environmental for FT only and error. Heritability estimates for ADG, DMI, RFI, MBW, and FT were: 0.21 +/- 0.09, 0.21 +/- 0.07, 0.40 +/- 0.11, 0.45 +/- 0.12, and 0.25 +/- 0.07, respectively. Repeatability of FT was 0.63. Pen size only had a significant effect on RFI (P<0.001). Month was significant for FT (P<0.001) with flight time increasing as the animal aged.