Vadroňová, Mariana
- Department of Applied Animal Science and Welfare, Swedish University of Agricultural Sciences
Abstract
This study aimed to improve the predictive accuracy of in vitro models for estimating in vivo methane (CH4) emissions in Nordic dairy systems by evaluating five forage-to-concentrate (F:C) ratios and incorporating a modelling approach based on ruminal mean retention time (MRT). The tested ratios included 100:0 (100 F), 80:20 (80 F), 60:40 (60 F), 40:60 (40 F), and 20:80 (20 F), where 100 F consisted solely of grass silage, and the remaining diets incorporated barley grain and rapeseed meal as concentrate. All diets were balanced for crude protein (20 % DM), but ether extract and neutral detergent fiber content decreased as concentrate levels increased. To improve the biological relevance of in vitro results, CH4 production was corrected using a ruminal MRT model to better simulate in vivo conditions. Higher concentrate inclusion linearly increased (P < 0.001) total gas and predicted in vivo CH4 production. However, after applying MRT adjustments, the modified model reduced the variation in CH4 predictions across F:C ratios, resulting in values that more closely reflected expected in vivo emissions. The pH declined (P < 0.001) at lower F:C ratios. Organic matter degradability (OMD) followed a quadratic pattern (P < 0.001), peaking in 60 F and 40 F diets and decreasing in 100 F and 20 F. While total volatile fatty acid concentrations were unaffected by F:C ratio, acetate proportion declined linearly (P < 0.001) as concentrate increased, whereas isobutyric and butyric acid proportions rose. Overall, these findings support the application of MRT-adjusted models to enhance the alignment between in vitro predictions and in vivo CH4 emissions.
Keywords
Forage-to-concentrate ratio; Methane production; Modelling; Nordic ruminant diets; Automated in vitro system
Published in
Animal Feed Science and Technology
2026, volume: 332, article number: 116611
Publisher: ELSEVIER
SLU Authors
Fant, Petra
- Department of Applied Animal Science and Welfare, Swedish University of Agricultural Sciences
- Department of Applied Animal Science and Welfare, Swedish University of Agricultural Sciences
Ramin, Mohammad
- Department of Applied Animal Science and Welfare, Swedish University of Agricultural Sciences
- Department of Applied Animal Science and Welfare, Swedish University of Agricultural Sciences
UKÄ Subject classification
Animal and Dairy Science
Publication identifier
- DOI: https://doi.org/10.1016/j.anifeedsci.2025.116611
Permanent link to this page (URI)
https://res.slu.se/id/publ/145772