Feed efficiency and meat quality of crossbred beef heifers classified according to residual feed intake

Abstract

This study aimed to evaluate feed efficiency and meat quality of 31 three-crossbred beef heifers during 84 days in a feedlot system. A 60:40 concentrate and sorghum silage ration on DM basis (ME = 2.73Mcal/kg of DM, CP = 11.90% DM) was fed ad libitum. Based on residual feed intake (RFI) calculations, the heifers were ranked in three groups of feed efficiency: High RFI (average mean = 0.776; n = 9), medium RFI (average mean = -0.010; n = 11), and low RFI (average mean = - 0.624; n = 11). High RFI heifers consumed 4.56% more DM per day than low RFI heifers (P <0.05). The ADG did not differ (P> 0.05) among RFI groups (1.40kg/day). No differences (P>0.05) were detected for digestibility of the nutrients: DM (64.00%), CP (60.01%), crude fat (72.90%), NDF (54.80%) and non-fibrous carbohydrate (NFC) (78.91%). There were no differences between low and high RFI groups for slaughter weight (475.00 vs. 479.55kg), hot carcass weight (259.09 vs. 261.44kg), Longissimus dorsi (LD) area (69.02 vs. 68.11 cm2), back-fat thickness (5.74 vs. 6.26 cm), shear force (5.45 vs. 5.19kg), sensorial traits of LD muscle, LD color (intensities L=40.47 a*=24.74 and b*=16.13) or commercial cuts yield. Low RFI heifers presented similar meat quality and carcass traits as high RFI heifers, however low RFI heifers consumed less DM (kg/d).

Performance, carcass traits, and non-carcass components of feedlot finished lambs from different residual feed intake classes

“…The RFI classes showed no differences in the neck, shoulder + shank, loin, rack, flank steak, rack cap off, leg, and HH section weight (P > 0.05, Table 6). Accordingly, a number of studies found no differences in the weight of beef cut from cattle in different RFI classes (GOMES et al, 2012;REIS et al, 2015;NASCIMENTO et al, 2016). This result was expected because the carcasses from the three efficiency classes exhibited similar weight and morphometric measures (Table 4).…”

Residual intake and gain for the evaluation of performance, non-carcass components, and carcass characteristics of confined crossbred Texel lambs

“…This fat layer may have contributed to a relatively low WLC (2.57 g/100 g), because fat protects carcasses against water loss during the cooling process . Gomes et al (2012) as well as Reis et al (2015) reported similar results and found no differences in LEA and SFT in the carcass of calves that had been grouped according to RFI level. Nascimento et al (2016) also did not observe differences in SFT when evaluating the longissimus lumborum of calves with varying levels of RFI and RIG.…”

“…Our results corroborate previous findings by Nascimento et al (2016), who evaluated HCW and HCY of Nellore calves and found no significant differences among RIG groups. Reis et al (2015) also found no significant differences in SBW and HCW in heifers with different RIG levels.…”

“…This premise is aligned with previous findings (Basarab et al, 2003) indicating decreased fat deposition in efficient animals grouped by RFI level. Nevertheless, Reis et al (2015) evaluated HH section carcass composition of calves grouped according to RFI and found no significant differences among groups.…”

Association between residual feed intake, digestion, ingestive behavior, enteric methane emission and nitrogen metabolism in Nellore beef cattle

“…This excess energy was probably directed toward high-energy metabolic processes in high RFI animals such as protein turnover (Cantalapiedra-Hijar et al, 2018), as well as less efficient mitochondrial activity (Kenny et al, 2018). Reis et al (2015) reported a 4.56% higher feed intake and similar apparent digestibility of nutrients when comparing high and low RFI animals, without differences in weight gain, hot carcass weight, Longissimus muscle area, or meat quality. These findings confirm that high RFI animals are unable to utilize the excess energy generated in an economically interesting manner when compared to low RFI animals.…”