Residual feed intake of purebred Angus steers: Effects on meat quality and palatability

Abstract

Relationships between residual feed intake (RFI) and other performance variables were determined using 54 purebred Angus steers. Individual feed intake and BW gain were recorded during a 70-d post-weaning period to calculate RFI. After the 70-d post-weaning test, steers were fed a finishing ration to a similar fat thickness (FT), transported to a commercial facility, and slaughtered. A subsample of carcasses (n = 32) was selected to examine the relationships among RFI, meat quality, and palatability. Steers were categorized into high (> 0.5 SD above the mean; n = 16), medium (mid; +/- 0.5 SD from the mean; n = 21), and low (< 0.5 SD below the mean; n = 17) RFI groups. No differences were detected in ADG, initial BW, and d 71 BW among the high, mid, and low RFI steers. Steers from the high RFI group had a greater DMI (P = 0.004) and feed conversion ratio (FCR; DMI:ADG; P = 0.002) compared with the low RFI steers. Residual feed intake was positively correlated with DMI (r = 0.54; P = 0.003) and FCR (r = 0.42; P = 0.002), but not with initial BW, d 71 BW, d 71 ultrasound FT, initial ultrasound LM area, d 71 ultrasound LM area, or ADG. The FCR was positively correlated with initial BW (r = 0.46; P = 0.0005), d 71 BW (r = 0.34; P = 0.01), and DMI (r = 0.40; P = 0.003) and was negatively correlated with ADG (r = -0.65; P = 0.001). There were no differences among RFI groups for HCW, LM area, FT, KPH, USDA yield grade, marbling score, or quality grade. Reflectance color b* scores of steaks from high RFI steers were greater (P = 0.02) than those from low RFI steers. There was no difference between high and low RFI groups for LM calpastatin activity. Warner-Bratzler shear force and sensory panel tenderness and flavor scores of steaks were similar across RFI groups. Steaks from high RFI steers had lower (P = 0.04) off-flavor scores than those from low RFI steers. Cook loss percentages were greater (P = 0.005) for steaks from low RFI steers than for those from mid RFI steers. These data support current views that RFI is independent of ADG, but is correlated with DMI and FCR. Importantly, the data also support the hypothesis that there is no relationship between RFI and beef quality in purebred Angus steers.

Genetics of meat quality and carcass traits and the impact of tenderstretching in two tropical beef genotypes

“…This result is consistent with the observation of Baker et al (2006) that, at a phenotypic level, reported RFI measured in Angus steers had no significant effect on objective tenderness measurements or taste panel scores. RFI had moderate genetic relationships with carcass composition traits (Table 7: r g = 0.49 with RIB, -0.42 with EMA and -0.61 with RBY), which were consistent across genotypes, suggesting that selection to improve RFI would produce carcasses which were genetically leaner, with larger EMA and higher RBY.…”

Biological mechanisms related to differences in residual feed intake in dairy cows

“…Feed intake and body size between divergent RFI groups Usually, the selection of cattle with low RFI decreased feed costs (Baker et al, 2006;Kundu et al 2014). Williams et al (2011) found that Holstein-Friesian dairy heifers with the 10% lowest RFI ate 1.7 kg less DM each day than the 10% highest RFI ones to achieve the same rate of growth.…”

“…Baker et al (2006) reported that low RFI Angus steers consumed less dry matter (DM) when compared with high RFI steers. Herd and Bishop (2000) and Nkrumah et al (2007) also found that selecting low RFI phenotypes would reduce feeding costs.…”

Residual feed intake of Angus beef cattle divergently selected for feed conversion ratio

“…RFI is calculated as the actual feed consumed minus the feed that the animal was expected to consume based on its mid-test weight and average daily gain (ADG). This measurement, which is expressed as the difference or residual, is phenotypically independent of growth rate and body weight in growing cattle (Kennedy et al, 1993;Arthur et al, 2001a,b;Archer et al, 2002;Herd et al, 2003;Baker et al, 2006). Most studies have found genetic independence as well (Herd and Bishop, 2000;Arthur et al, 2001b).…”