Comparison of in vitro and in vivo methane production in dairy cows

TY - ABST

T1 - Comparison of in vitro and in vivo methane production in dairy cows

AU - Olijhoek, Dana

AU - Chassé, Élisabeth

AU - Battelli, Marco

AU - Curtasu, Mihai Victor

AU - Thorsteinsson, Mirka Mølgaard

AU - Kjeldsen, Maria Holst

AU - Wang, Wenji

AU - Giagnoni, Giulio

AU - Maigaard, Morten

AU - Børsting, Christian Friis

AU - Weisbjerg, Martin Riis

AU - Lund, Peter

AU - Nielsen, Mette Olaf

N1 - Conference code: 74

PY - 2023

Y1 - 2023

N2 - Ideally, in vivo methane production from individual cows fed different diets could be predicted by a low-cost in vitro method. Therefore, this study aimed to assess the correlation between in vivo methane emission from dairy cows measured using respiration chambers or GreenFeed (C-Lock Inc, Rapid City, USA) and in vitro methane production when identical diets were incubated in a system simulating rumen fermentation (Ankom RF, Ankom Technology, Macedon, USA). Two experiments were conducted. In in vitro Exp. 1, total gas and methane production were determined when dried samples (0.5 g) of 43 different TMRs (from 11 feeding trials) and silages (maize and grass) as control feeds were incubated in 90 ml buffered rumen fluid obtained from 3 heifers (pooled). In in vitro Exp. 2, TMR samples (0.5 g) with high (63% of DM) and low content (35% of DM) of forage were incubated in 90 ml buffered rumen liquid obtained and separately tested for 16 Danish Holstein cows fed each of these diets in 2 different experimental periods. All in vitro incubations lasted 48 h to record total gas production and gas samples were collected at 24 h to determine methane production. Data were analyzed as Pearson correlations. Preliminary results of Exp. 1 showed a weak correlation (r = 0.35; P = 0.02) between methane production from the diets determined in vitro (ml CH4/g incubated DM) and in vivo (L CH4/kg DMI). Graphical visualization of in vitro and in vivo methane production of Exp. 2 showed clustering by the diet fed to the cow, but not by the diet incubated in vitro. The correlation between in vitro and in vivo methane production was stronger when cows were fed a diet low in forage (r = 0.56; P = 0.001) than high in forage (r = 0.17; P = 0.34). Further statistical analyses will be performed. These first results highlight the impact of the diet fed to cows that deliver rumen liquid for in vitro trials and the lack of considerable consistency in methane production assessed in vitro compared to in vivo, and this was particularly pronounced when cows were fed diets high in forage.

AB - Ideally, in vivo methane production from individual cows fed different diets could be predicted by a low-cost in vitro method. Therefore, this study aimed to assess the correlation between in vivo methane emission from dairy cows measured using respiration chambers or GreenFeed (C-Lock Inc, Rapid City, USA) and in vitro methane production when identical diets were incubated in a system simulating rumen fermentation (Ankom RF, Ankom Technology, Macedon, USA). Two experiments were conducted. In in vitro Exp. 1, total gas and methane production were determined when dried samples (0.5 g) of 43 different TMRs (from 11 feeding trials) and silages (maize and grass) as control feeds were incubated in 90 ml buffered rumen fluid obtained from 3 heifers (pooled). In in vitro Exp. 2, TMR samples (0.5 g) with high (63% of DM) and low content (35% of DM) of forage were incubated in 90 ml buffered rumen liquid obtained and separately tested for 16 Danish Holstein cows fed each of these diets in 2 different experimental periods. All in vitro incubations lasted 48 h to record total gas production and gas samples were collected at 24 h to determine methane production. Data were analyzed as Pearson correlations. Preliminary results of Exp. 1 showed a weak correlation (r = 0.35; P = 0.02) between methane production from the diets determined in vitro (ml CH4/g incubated DM) and in vivo (L CH4/kg DMI). Graphical visualization of in vitro and in vivo methane production of Exp. 2 showed clustering by the diet fed to the cow, but not by the diet incubated in vitro. The correlation between in vitro and in vivo methane production was stronger when cows were fed a diet low in forage (r = 0.56; P = 0.001) than high in forage (r = 0.17; P = 0.34). Further statistical analyses will be performed. These first results highlight the impact of the diet fed to cows that deliver rumen liquid for in vitro trials and the lack of considerable consistency in methane production assessed in vitro compared to in vivo, and this was particularly pronounced when cows were fed diets high in forage.

M3 - Conference abstract for conference

SP - 1014

T2 - <br/>74th Annual Meeting of European Federation of Animal Science

Y2 - 26 August 2023 through 1 September 2023

ER -