A better understanding of the factors regulating feed efficiency and their potential as predictors of feed efficiency in cattle is needed. Therefore, the potential of three classes of traits, namely, feeding behavior characteristics: daily time at feeder (TF; min/day), time per meal (TM; min), meal size (MS; g DM), eating rate (ER; g DM/min), number of daily meals (NM) and daily visits to the f...

One option that can be used to select cattle for improving feed efficiency is to select for genes affecting residual feed intake. Previous studies using two groups of cattle, the Trangie Angus residual feed intake (RFI) selection line cattle and the Davies Jersey x Limousin gene mapping cattle have identified five chromosomal regions or QTL that have significant effects on net feed efficiency. ...

Heat stress (HS) is one of the costliest issues in the U.S. pork industry. Aims of the present study were to determine the consequences of repeated exposure to HS on growth performance, and the effects of a high fiber diet, the genetic potential for high lean tissue accretion, and the genetic potential for residual feed intake (RFI) on resilience to HS. Barrows (n = 97) from three genetic lines...

Data were recorded in two lines divergently selected for residual feed intake (RFI) for eight generations (G0 to G7). First, an animal mixed model was applied to the full dataset to estimate least square means (LsCG) of contemporary group (CG) effects for average daily gain (ADG, 3189 pigs, 80 CG) and backfat thickness (BFT, 1668 pigs, 44 CG). Second, LsCG were used as covariates in linear mode...

Residual feed intake (RFI) is an increasingly used trait to analyze efficiency in livestock, and some sectors such as dairy cattle, it one of the most frequently traits. Although principle for calculating RFI always same (i.e., using residual a regression on performance predictors), wide range models are found literature, with different predictors, ways considering intake, more recently, statis...

Improvement of feed efficiency in pigs has been achieved essentially by increasing lean growth rate, which resulted in lower feed intake (FI). The objective was to evaluate the impact of strategies for improving feed efficiency on the dynamics of FI and growth in growing pigs to revisit nutrient recommendations and strategies for feed efficiency improvement. In 2010, three BWs, at 35±2, 63±9 an...

The aim of the study was to evaluate the consequences of a divergent selection for residual feed intake (RFI) during growth in a temperate environment (TEMP) on sow performance in a tropical environment (TROP). Sows came from a selection experiment conducted at INRA in which 2 lines were selected for larger (RFI(+)) or smaller (RFI(─)) feed intake than predicted from performance. In the first a...

and Implications The objective of this study was to determine low and high-RFI gilt sickness behavior when challenged with lipopolysaccharide (LPS). This work was conducted with seven low residual feed intake gilts (RFI) and eight high RFI gilts (63±4 kg BW) from the 8th generation of the ISU Yorkshire RFI selection lines. Gilts were challenged intramuscularly with 30 µg/kg BW Escherichia coli ...

Feed efficiency is an important trait in pig production, with evidence to suggest that the efficiencies of a variety of biological systems contribute to variation in this trait. Little work has been conducted on the contribution of the intestinal innate immune response to divergence in feed efficiency. Hence, the objective of this study was to examine select bacterial populations and gene expre...

Mechanisms underlying variation in residual feed intake (RFI), a heritable feed efficiency measure, are poorly understood while the relationship between RFI and meat quality is uncertain. To address these issues, 2 divergent cohorts consisting of High (HRFI) and Low (LRFI) RFI individuals were created by assessing RFI in 48 Angus-sired steers during a 70 d feeding trial to identify steers with ...