Bioperformance evaluation of various summer pasture and winter feeding strategies for cow-calf production
Bibliographic record
Abstract
Legesse, G., Small, J. A., Scott, S. L., Kebreab, E., Crow, G. H., Block, H. C., Robins, C. D., Khakbazan, M. and McCaughey, W. P. 2012. Bioperformance evaluation of various summer pasture and winter feeding strategies for cow-calf production. Can. J. Anim. Sci. 92: 89–102. Bioperformance of two summer pasture and four winter feeding cow-calf production strategies in the western Canadian Parkland was evaluated. Diet composition and animal data were collected over 5 production years. Each production year began with fixed-time artificial insemination (TAI) of cows and turnout of cow-calf pairs (n=288 yr−1 including 76 primiparous replacement cows) assigned to either alfalfa-grass (AG, n=9 paddocks) or grass (G, n=9 paddocks) pastures until weaning. Post-weaning, pregnant cows (n=240 yr−1) were assigned to either extended-grazing (EG, n=120) of dormant regrowth of perennial pastures and swathed annual crops, or one of three diets fed in a drylot (DL): hay (HY, n=40), straw/barley (SB, n=40; 70% oat straw:30% steam-rolled barley grain DM), and silage/straw (SS, n=40; 40% barley silage:60% oat straw DM). Common diets were used for all treatment groups between the weaning and winter feeding period, as well as between the pre-calving and summer grazing period. Cow and calf body weight (BW) gains were higher (P<0.05) for AG than G pasture until the third production year and the advantage diminished as the carrying capacity declined. The latter may be attributed to a lack of spring/summer moisture. Further, G pastures required more nitrogen fertilizer to achieve the same level of bioperformance as that of AG pastures in years 4 and 5. Cows in the EG treatment maintained BW better than those in the DL treatment (especially those cows receiving the SS diet) except in year 5 (P<0.05) in which drought resulted in lower body weights for cows in the EG treatment. On all treatments, cows maintained BCS that supported reproductive function; however, fertility to TAI was lowest (P<0.05) in years 4 and 5. Cows in the DL group had a 1.8 times greater risk of being culled before turnout and as a result lower (P<0.05) rates of calf survival to weaning. In conclusion, AG pastures and EG are important alternatives to further develop for cow-calf production in western Canada.
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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 | 0.001 | 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) | 0.000 | 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 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".