Evidence map›Paper›PMID 42143724›Full record

ArticleJournal of animal science2026

Predicting dry matter intake in gestating ewes using greenhouse gas measurements from portable accumulation chambers.

Gareth F Difford, Jette Jakobsen, Ingjerd Dønnem, Geir Steinheim, Bente A Åby

Abstract read
In one paragraph

Article in Journal of animal science, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

5 authors.

Gareth F DiffordInstitute of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, Ås, N-1432, Norway.
Jette JakobsenThe Norwegian Association of Sheep and Goat Breeders, Ås, N-1430, Norway.
Ingjerd DønnemInstitute of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, Ås, N-1432, Norway.
Geir SteinheimInstitute of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, Ås, N-1432, Norway.
Bente A ÅbyInstitute of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, Ås, N-1432, Norway.

Funding

2018 Joint Call of the Cofund ERA-Nets FACCE ERA-GAS 696356Coordination and Support Action (CSA)European Union's Horizon Europe research and innovation (R&I) 101056828Grass2GasGreen ERA-HubICT-AGRI 2 618123SusAn 696231The Research Council of Norway 309158
6 · The paper itself

Abstract

Accurate measurement of dry matter intake (DMI) in sheep is logistically challenging and costly, particularly under commercial conditions and across diverse production systems. This study evaluated whether methane (CH4), carbon dioxide (CO2) and oxygen (O2) gas measurements from portable accumulation chambers (PAC), combined with bodyweight (BW) and eating time (ET), can predict DMI in gestating ewes. Two indoor feeding trials were conducted at a single research facility using Norwegian White Sheep (NWS) and Old Norwegian Spaelsau (ONS). Trial 1 used two grass silage qualities in a 2 × 2 factorial design; Trial 2 used fresh-cut herbage in a repeated-measures design. Ewes (n = 40 per trial; 29 in common) were individually housed with access to one feed bin and fed ad libitum. Daily DMI was recorded using automated feed bins, and PAC measurements of CH4, CO2, and O2 were collected on 20 d per ewe per trial. After quality control, 1,830 ewe d records remained. Supervised learning models were trained on ewe-identity-blocked training sets and evaluated on external test sets stratified by trial and breed. In this particular dataset, random forest (RF) models outperformed regularized regression, partial least squares, k-nearest neighbors, support vector machines, and a deep neural network. The best RF model, using PAC traits, LW, and ET (Pred_DMI3), achieved R2 = 0.77, root mean square error of 279 g/d, and mean absolute percentage error = 13.8% in the combined test set. Models using only PAC traits performed comparably to models including BW and ET with only marginal losses in validation metrics. Mixed-model analyses indicated strong individual-level correlations between predicted and observed DMI (rᵢ = 0.79-0.81) after adjusting for breed, diet, and trial. These results demonstrate that short-term PAC-derived gas traits can provide scalable proxies for daily DMI in gestating ewes under controlled indoor conditions, with potential application in intake phenotyping and benchmarking.

Indexed as

Animal HusbandryEatingGreenhouse GasesAnimal FeedAnimalsCarbon DioxideDietFemaleMethaneOxygenPregnancySheepCarbon DioxideGreenhouse GasesMethaneOxygencarbon dioxidedry matter intakemachine learningmethaneportable accumulation chamberssheep

Identifiers

PMID42143724
PMCPMC13281912

What OpenQuestion holds

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LicenceCC BY
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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.