Short communication: Relationship between herd intramammary infection incidence and elimination rate during the dry period
Bibliographic record
Abstract
The objective of the study was to explore the relationship between herd dry period (DP) intramammary infection (IMI) incidence and elimination rates. A cohort of 91 Canadian dairy herds was recruited and followed in 2007 and 2008. Universal dry cow therapy was widely adopted among the participating herds. At the beginning of years 2007 and 2008, a sample of 15 cows was selected in each herd. A series of quarter-milk samples consisting of 2 predry and 2 postcalving samples were collected on each quarter of these 30 cows. Milk samples were analyzed using routine bacteriological milk culture, and predry and postcalving IMI statuses of these quarters were established using parallel interpretation of the 2 predry and 2 postcalving tests, respectively. Intramammary infection status was defined as IMI by Staphylococcus aureus, streptococci other than Streptococcus agalactiae, coagulase-negative staphylococci (CNS), or Corynebacterium spp. Incidence and elimination rates of DP IMI were computed for each herd. Lowess curves and linear regression were used to investigate the association between DP IMI incidence and elimination rates. Significant negative associations were found between incidence and elimination rates of Staph. aureus and CNS. The relationship between incidence and elimination rates was nonlinear for CNS, with a relatively strong negative relationship between DP IMI incidence and elimination rates for herds with relatively low DP IMI incidence (<0.10 new IMI/quarter-month). For herds with higher DP IMI incidence (≥ 0.10 new IMI/quarter-month), a weaker negative relationship was observed between rates. No significant associations could be seen between DP incidence and elimination rates of streptococci other than Strep. agalactiae and of Corynebacterium spp. These results suggest that, conversely to the general belief, acquisition of new IMI and elimination of existing IMI during the DP may be driven, at least for staphylococci, by common mechanisms. The use of management strategies that would lead to the selection of pathogens less well adapted to the host could explain the associations observed between acquisition and elimination of IMI over the DP.
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".