Brahman and Brahman crossbred cattle grown on pasture and in feedlots in subtropical and temperate Australia. 3. Feed efficiency and feeding behaviour of feedlot-finished animals
Bibliographic record
Abstract
The objective of this experiment was to quantify differences in feed efficiency and feeding behaviour of 470 heifers and steers by Brahman, Belmont Red, Santa Gertrudis, Angus, Hereford, Shorthorn, Charolais and Limousin sires mated to Brahman dams. Animals were bred in subtropical Queensland and finished in a temperate New South Wales feedlot. Animals averaged 598 days of age and 425.8 kg at the start of the feed intake test period. Sire breeds did not differ for eating rate, feed conversion ratio or relative growth rate. Generally, higher daily feed intakes (DFI) corresponded with higher average daily gains (ADG). Straightbred Brahmans fed the most frequently (16.6 ± 0.8 sessions/day; P < 0.05) but spent the least time eating of all breeds (67.4 ± 2.7 min/day; P < 0.001). Least squares means for Brahman, Belmont Red, Santa Gertrudis, Angus, Hereford, Shorthorn, Charolais and Limousin sired progeny, respectively, for residual feed intake (RFI; P < 0.05) were 0.02 ± 0.16, 0.14 ± 0.13, –0.10 ± 0.23, 0.54 ± 0.17, –0.27 ± 0.18, 0.29 ± 0.18, –0.46 ± 0.16 and –0.21 ± 0.13 kg/day, and for ADG (P < 0.001) were 1.06 ± 0.05, 1.17 ± 0.04, 1.52 ± 0.08, 1.47 ± 0.06, 1.46 ± 0.06, 1.46 ± 0.06, 1.35 ± 0.06 and 1.38 ± 0.05 kg/day. While straightbred Brahmans did not differ from all other sire breeds for RFI, their lower appetite relative to crossbred contemporaries resulted in the lowest DFI (P < 0.001) and lowest ADG (P < 0.001) overall. Angus sired crosses were the least efficient feeders and spent the most time eating, consumed the most feed and had the highest RFI, but were not significantly different to Santa Gertrudis and Shorthorn crosses for these traits. Angus sired crosses spent 24.1 and 15.4 min/day more time eating (P < 0.001) than straightbred Brahmans and Charolais crosses, and consumed 35 and 13% more feed (P < 0.001) respectively. Charolais sired crosses were the most feed efficient with the lowest RFI and intermediate DFI, and did not differ significantly from the highest ranking sire breeds for ADG or Kleiber ratio. While Belmont Red crosses did not differ from all breeds for RFI, they had significantly lower DFI than British and Santa Gertrudis crosses resulting in lower ADG (P < 0.001) relative to these sire breeds. Therefore, selection of Charolais, Hereford, Limousin and Santa Gertrudis sire breeds would result in the most feed efficient (low RFI) crosses with Brahman without any sacrifice in ADG.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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 itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".