The repeatability of feed intake and feed efficiency in beef cattle offered high-concentrate, grass silage and pasture-based diets

Abstract

Breeding values for feed intake and feed efficiency in beef cattle are generally derived indoors on high-concentrate (HC) diets. Within temperate regions of north-western Europe, however, the majority of a growing beef animal’s lifetime dietary intake comes from grazed grass and grass silage. Using 97 growing beef cattle, the objective of the current study was to assess the repeatability of both feed intake and feed efficiency across 3 successive dietary test periods comprising grass silage plus concentrates (S+C), grazed grass (GRZ) and a HC diet. Individual DM intake (DMI), DMI/kg BW and feed efficiency-related parameters, residual feed intake (RFI) and gain to feed ratio (G : F) were assessed. There was a significant correlation for DMI between the S+C and GRZ periods (r = 0.32; P < 0.01) as well as between the S+C and HC periods (r = 0.41; P < 0.001), whereas there was no association for DMI between the GRZ and HC periods. There was a significant correlation for DMI/kg BW between the S+C and GRZ periods (r = 0.33; P < 0.01) and between the S+C and HC periods (r = 0.40; P < 0.001), but there was no association for the trait between the GRZ and HC periods. There was a significant correlation for RFI between the S+C and GRZ periods (r = 0.25; P < 0.05) as well as between S+C and HC periods (r = 0.25; P < 0.05), whereas there was no association for RFI between the GRZ and HC periods. Gain to feed ratio was not correlated between any of the test periods. A secondary aspect of the study demonstrated that traits recorded in the GRZ period relating to grazing bite rate, the number of daily grazing bouts and ruminating bouts were associated with DMI (r = 0.28 to 0.42; P < 0.05 - 0.001), DMI/kg BW (r = 0.36 to 0.45; P < 0.01 - 0.001) and RFI (r = 0.31 to 0.42; P < 0.05 - 0.001). Additionally, the number of ruminating boli produced per day and per ruminating bout were associated with G : F (r = 0.28 and 0.26, respectively; P < 0.05). Results from this study demonstrate that evaluating animals for both feed intake and feed efficiency indoors on HC diets may not reflect their phenotypic performance when consuming conserved forage-based diets indoors or when grazing pasture.

Effect of divergence in residual methane emissions on feed intake and efficiency, growth and carcass performance, and indices of rumen fermentation and methane emissions in finishing beef cattle

“…Additionally, daily animal visitation to the GEM throughout the methane measurement period was within the range (1.3 to 5.08 visits/d) reported by others ( Velazco et al, 2016 ; Alemu et al, 2017 ; Arthur et al, 2017 ; Renand et al, 2019 ) and further strengthens the validity of the methane recording technique implemented in this experiment. The absolute range and differences in growth, performance, feed efficiency, and carcass data between animal sexes and genotypes were comparable to previous production values generated from the same feed efficiency performance test center over the preceding 10 yr ( Crowley et al, 2010 ; Kelly et al, 2011 ; Kelly et al, 2019 ; Lahart et al, 2020 ). DME were positively correlated with feed intake, growth, and carcass output, in line with previous studies ( Bird-Gardiner et al, 2017 ; Renand et al, 2019 ).…”

Effect of Post-Grazing Sward Height, Sire Genotype and Indoor Finishing Diet on Steer Intake, Growth and Production in Grass-Based Suckler Weanling-to-Beef Systems

“…The superior animal growth of PGSH-6 at pasture was associated with a greater DMI of higher (statistical tendency) OMD herbage compared to PGSH-4. Herbage DMI or grazing behaviour was not measured in previous studies evaluating PGSH for beef cattle in temperature pastures [ 10 , 11 , 36 ]; however, grazing behaviour parameter values obtained for PGSH-6 steers were similar to those reported in the literature for beef cattle grazing pasture to a similar height [ 38 , 39 ]. In the current study, the greater herbage DMI for PGSH-6 than PGSH-4 was mainly due to grazing behaviour differences that emerged during the last 24 h rather than the first 24 h of a 48-h allocation of fresh herbage.…”

“…This could be due to the similarity in herbage NDF and ADF concentrations between the PGSH treatments. The greater ruminating mastication rate for PGSH-6 could be due to the higher intake rate [ 44 ], as a significant positive, albeit low, correlation (0.25) between herbage DMI and ruminating mastication rate in grazing steers has been reported [ 38 ].…”

Common and diet-specific metabolic pathways underlying residual feed intake in fattening Charolais yearling bulls

“…The lack of universally accepted biomarkers of RFI might be due to the difficulty of identifying metabolites driven by the inter-individual variability rather than by dietary treatments, the latter having a strong impact on plasma metabolome 6 , 11 . Moreover, the inconsistencies across studies could stem from the use of different types of diets since a potential RFI Diet interaction has been evoked in a few works 12 , 13 . This could mean that biological mechanisms underlying RFI, and thus the associated biomarkers, might differ depending on the nature of the diet and finally to the type of absorbed nutrients.…”