Selective protein loss in lactating sows is associated with reduced litter growth and ovarian function1
Bibliographic record
Abstract
This study was designed to test the degree of protein loss that may be sustained by lactating sows before milk biosynthesis and ovarian function will be impaired. First-parity Camborough x Canabrid sows were allocated to receive isocaloric diets (61 +/- 2.0 MJ of ME/d) and one of three levels of protein intake in lactation: 1) 878 g of CP and 50 g of lysine/d (n = 8), 2) 647 g of CP and 35 g of lysine/d (n = 7), or 3) 491 g of CP and 24 g of lysine/d (n = 10). Every 5 d during a 23-d lactation, sow live weight, backfat depth, and litter weight were recorded, and a preprandial blood sample was collected. Milk samples were collected on d 10 and 20 of lactation. Sows were slaughtered on the day of weaning, and liver and ovarian variables were measured. Lower dietary protein intakes elicited progressively larger live weight losses during lactation (-13, -17, and -28 +/- 2.3 kg; P < 0.001), but similar and minimal backfat losses (-1.3 +/- 0.29 mm). Approximately 7, 9, and 16% of the calculated body protein mass at parturition was mobilized by d 23. Lactation performance did not differ among treatments until d 20, at which time approximately 5, 6, and 12% of the calculated protein mass at parturition had been lost. The milk protein concentration on d 20 of lactation reflected the amount of body protein lost, and was lowest (P < 0.05) in sows that lost the most protein. After d 20, piglet growth rate decreased (P < 0.05) in a manner related to the amount of body protein lost. At weaning, ovarian function was suppressed in sows that had mobilized the most body protein; they had fewer medium-sized follicles (> 4 mm; P < 0.05), their follicles contained less (P < 0.01) follicular fluid, and had lower estradiol (P < 0.05) and IGF-I (P < 0.10) contents. Culture media containing 10% pooled follicular fluid (vol/vol) from high-protein-loss sows were less able to support nuclear and cytoplasmic maturation of oocytes in vitro, evidenced by more oocytes arrested at metaphase I (P < 0.05) and showing limited cumulus cell expansion (P < 0.06). Plasma insulin and IGF-I concentrations did not seem to be related to the observed differences in animal performance. Our data suggest that no decline in lactational performance or ovarian function when a sow loses approximately 9 to 12% of its parturition protein mass. However, progressively larger decreases in animal performance are associated with a loss of larger amounts of body protein mass at parturition.
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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 | 0.001 |
| 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 | 0.001 |
| 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".