Association between residual feed intake and enteric methane emissions in Hereford steers

Abstract

The objective of this study was to quantify the emissions of enteric CH4 from growing Hereford steers raised under feedlot conditions based on contrasting levels of residual feed intake (RFI). A repeated measurements experiment was conducted over 20 d to determine CH4 production from two groups of nine Hereford steers, with contrasting RFI values (mean ± SD): low RFI (LRFI group; −0.78 ± 0.22 kg DMI/d) vs. high RFI (HRFI group; 0.83 ± 0.34 kg DMI/d). Steers were selected from a larger contemporary population in which the RFI was evaluated. Steers were maintained under confined conditions with ad libitum access to water and feed, comprising a total mixed ration of 55% sorghum silage, 21% barley silage, 21% corn grain, and 3% protein–mineral–vitamin–premix, provided twice a day. Before the beginning of CH4 measurements, the live weight of both groups of animals was determined, which on average (±SEM) was 357.0 ± 5.11 and 334.0 ± 10.17 kg in the LRFI and HRFI groups, respectively. Methane emission (g/d) was measured on each animal with the sulfur hexafluoride (SF6) tracer technique, during two consecutive periods of 5 d. Individual daily intake and feeding behavior characteristics were measured using a GrowSafe automated feeding system (Model 6000, GrowSafe Systems Ltd, Airdrie, Alberta, Canada). Methanogens in the ruminal content were quantified using quantitative polymerase chain reaction with primers targeting the mcrA gene. Methane emission was near 27% lower in animals with LRFI when expressed in absolute terms (g/d; 26.8%; P = 0.009), by unit of dry matter intake (g CH4/kg; 27.9%, P = 0.021), or as % of gross energy intake (26.7%; P = 0.027). These differences could not be explained by differences in amount of total of methanogens (average = 9.82 log10 units; P = 0.857). However, there were some differences in animal feeding behavior that could explain these differences (e.g., LRFI animals tended to spend less time in feeders). Our results suggest that, in Hereford steers, the selection by RFI values is a promising mitigation strategy for the reduction of the emission of enteric CH4.

Phenotypic association among performance, feed efficiency and methane emission traits in Nellore cattle

“…Greater reductions in enteric CH 4 emissions (15–30%) were reported in the literature for more efficient taurine animals [ 10 , 13 , 32 ] compared to the reduction of approximately 5% in the emission of zebuine animals classified as negative RFI in the present study ( Table 3 ). Results similar to those of the present study were observed in crossbred taurine heifers and cows classified as more efficient, with a daily CH 4 reduction of 2.5% and 3.7%, respectively, compared to less efficient animals [ 34 ].…”

“…Some studies evaluating CH 4 emission in animals classified as negative and positive RFI reported differences in emissions per kg of DMI, although they found no differences in CH 4 production [ 30 , 33 ]. However, other studies reported lower CH 4 emissions and lower CH 4 emission per DMI in negative RFI animals [ 29 , 32 ]. One explanation would be a lower particle passage rate in the rumen due to differences in feeding behavior since more efficient animals spend less time feeding and therefore exhibit a higher feeding rate than positive RFI animals [ 19 , 32 ].…”

“…However, other studies reported lower CH 4 emissions and lower CH 4 emission per DMI in negative RFI animals [ 29 , 32 ]. One explanation would be a lower particle passage rate in the rumen due to differences in feeding behavior since more efficient animals spend less time feeding and therefore exhibit a higher feeding rate than positive RFI animals [ 19 , 32 ]. Residual feed intake is an intrinsic trait of the individual that reflects maintenance requirements [ 36 ]; thus, another explanation for the lower CH 4 emissions would be a lower energy intake of negative RFI animals compared to positive RFI animals [ 29 ], since CH 4 emission is positively associated with energy intake and differences in digestibility, CH 4 emissions, heat production and energy retention are the main factors responsible for the variation of RFI between animals [ 13 ].…”

Dietary mitigation of enteric methane emissions from ruminants: A review of plant tannin mitigation options

“…IRC = indirect respiratory chamber; GF = GreenFeed system (C-Lock Inc., Rapid City, SD, USA). Sources: Dini et al. (2019 ; beef, BW = 357 kg BW; SF 6 ); Hegarty et al.…”

Animal as the Solution: Searching for Environmentally Friendly Dairy Cows

“…Several studies have investigated the use of breeding for lower residual feed intake (RFI) as a way to reduce CH 4 production [93][94][95]. A scenario was conducted modeling feed intake and CH 4 production rates in an Australian beef herd selected for low RFI compared to a national Australian herd for 25 years [96].…”