Genetic associations between feed efficiency measured in a performance test station and performance of growing cattle in commercial beef herds

Abstract

Interest in selection for improved feed efficiency is increasing, but before any steps are taken toward selecting for feed efficiency, correlations with other economically important traits must first be quantified. The objective of this study was to quantify the genetic associations between feed efficiency measured during performance testing and linear type traits, BW, live animal value, and carcass traits recorded in commercial herds. Feed efficiency data were available on 2,605 bulls from 1 performance test station. There were between 10,384 and 93,442 performance records on type traits, BW, animal value, or carcass traits from 17,225 commercial herds. (Co)variance components were estimated using linear mixed animal models. Genetic correlations between the muscular type traits in commercial animals and feed conversion ratio (-0.33 to -0.25), residual feed intake (RFI; -0.33 to -0.22), and residual BW gain (RG; 0.24 to 0.27) suggest that selection for improved feed efficiency should increase muscling. This is further evidenced by the genetic correlations between carcass conformation of commercial animals and feed conversion ratio (-0.46), RFI (-0.37), and residual BW gain (0.35) measured in performance-tested animals. Furthermore, the genetic correlations between RFI and both ultrasonic fat depth and carcass fat score (0.39 and 0.33, respectively) indicated that selection for improved RFI will result in leaner animals. It can be concluded from the genetic correlations estimated in this study that selection for feed efficiency will have no unfavorable effects on the performance traits measured in this study and will actually lead to an improvement in performance for some traits, such as muscularity, animal price, and carcass conformation. Conversely, this suggests that genetic selection for traits such as carcass quality, muscling traits, and animal value might also be indirectly selecting for more efficient animals.

Visceral organ weights, digestion and carcass characteristics of beef bulls differing in residual feed intake offered a high concentrate diet

“…Although bulls of low and high RFI in the current study had similar carcass conformation, which reflects similar LD depth, the negative correlation between RFI and carcass conformation score concurs with Crowley et al (2011) who found that RFI had a negative genetic correlation with carcass conformation (r = − 0.21), arising from improved muscularity in low RFI animals. A meta-analysis of genetic correlations between RFI and carcass conformation score by Berry and Crowley (2013) found that, in general, RFI tends to be negatively correlated with carcass conformation in beef cattle.…”

“…Previous studies with bulls have shown that high RFI animals have a greater content of subcutaneous body fat than those of low RFI (Lancaster et al, 2009;Smith et al, 2010;Kelly et al, 2011). Similarly, Crowley et al (2011) found that RFI had a positive phenotypic (r = 0.26; P < 0.05) and genetic (r = 0.39) correlation with fat depth in bulls. However, in the current study, RFI had no significant effect on ribfat, backfat or rump fat depth.…”

“…However Crowley et al (2011), found that the genetic correlation between RFI and carcass fat score was positive (r = 0.33) and Mao et al (2013), found that the genetic correlation between RFI and carcass grade fat was positive (r = 0.42) in Charolais steers but was close to zero (r = 0.02) in Angus steers. Differences in the propensity for fat accreation between different beef breeds, coupled with variation in carcass fat determination, may be contributing to the contrasting genetic correlations between RFI and carcass fatness observed between studies.…”

Grazed grass herbage intake and performance of beef heifers with predetermined phenotypic residual feed intake classification

“…Studies with heifers (Kelly et al, 2010a), beef cows (Lawrence et al, 2011a) and steers (Basarab et al, 2003;Nkrumah et al, 2004) found that animals ranked on the basis of RFI did not differ in morphological size. Similarly, Crowley et al (2011) found no significant genetic correlation between RFI and skeletal measurements; however, they did detect a negative phenotypic correlation (P , 0.05) between RFI and pelvis length (r 5 20.15) and width of hips (r 5 20.19).…”

Genetic differences based on a beef terminal index are reflected in future phenotypic performance differences in commercial beef cattle

“…The statistical analysis of large beef cattle databases has clearly revealed heritable genetic differences in many animal characteristics including animal growth rate (Burfening et al, 1981;Arthur et al, 2001;Crowley et al, 2011), carcass conformation (Evans et al, 2007;Pabiou et al, 2009), feed intake and efficiency (Bouquet et al, 2009;Berry and Crowley, 2012;Berry and Crowley, 2013), and reproductive performance (Phocas and Sapa 2004;Berry and Evans, 2014). The impact of animal genetic differences for performance traits on subsequent phenotypic performance has been documented in controlled experiments that compared animals divergent in genetic merit for an individual trait (Crews et al, 2006;Keane and Diskin, 2007;Campion et al, 2009) or a combination (i.e.…”