A meta-analysis of the sources of variation in the environmental impacts of different broiler production systems
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
1. Shifting to higher welfare systems is expected to increase their environmental impact and mitigation strategies need to be identified. The environmental impacts associated with various broiler production systems (BPS: conventional, higher welfare indoors, free-range or organic) and the characteristics of BPS which contribute to these impacts were investigated via a literature review and meta-analysis.2. The impact metrics considered were global warming (GWP), acidification and eutrophication potentials, NH3 emissions, land use, water use, energy use (EU) and biodiversity. Due to the paucity of data, analysis was limited to the impacts of the characteristics of the BPS: stocking density (STD), slaughter weight (SW), feed conversion ratio (FCR), on GWP, NH3 emissions and EU.3. After correction for system boundaries and functional units, no statistical effects of BPS on GWP were found, while higher welfare systems were associated with higher EU. Reduced STD was associated with reductions in GWP and EU. The SW was positively associated with GWP and NH3 emissions, while higher FCR was associated with increased NH3 emissions and EU.4. Environmental impacts arose from feed-associated activities (>75%). Most of the GWP impacts were associated with land use change (LUC), especially when associated with ‘unsustainable’ soya. High variation in values for different environmental metrics within BPS indicated a lack of standardisation in the assessment of environmental impact across the industry.5. The results suggested that practices within a system contributed greatly to the environmental impact of the system. Rather than comparing systems, it may be more productive to focus on improving practices that have the potential to reduce environmental impacts within a system, without compromising animal welfare.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.003 |
| Science and technology studies | 0.000 | 0.002 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it