Vaccination and risk factors for bovine respiratory disease in dairy heifer calves
Bibliographic record
Abstract
This thesis is an investigation of the associations of vaccination, risk factors and viral antibody titres with bovine respiratory disease (BRD) in dairy calves. A total 2874 heifer calves from 19 commercial dairy farms in Minnesota and Ontario were enrolled in a randomized clinical trial within the first week of life. In this population with an overall low incidence of failure of passive transfer (FPT) and mortality, and moderate incidence of BRD, vaccination with a multivalent MLV vaccine at 2 and/or 5 weeks of age was not associated with a decreased risk of BRD or death, or with growth to 3 months of age. Reasons for these findings may include: interference by maternal antibodies, unresponsiveness of the neonatal immune system, timing of immune protection, disease caused by pathogens other than the viruses in the vaccine, or herd immunity. Factors associated with an increase risk of BRD included FPT, herd-level incidence of BRD, season of birth, navel dipping, and being treated for diseases other than diarrhea or dullness. Supplemental antibody products were associated with a reduced incidence. Risk of mortality was increased by herd-level incidence of BRD, and calf-level treatment for BRD and other diseases. This study reinforces the importance of good colostrum management for its effects on disease, mortality and growth. It also highlights the significant effects of calfhood disease, showing that improving calf health can improve growth and survival. Vaccination with a multivalent MLV vaccine at 2 and/or 5 weeks of age did not influence the rate of decline of antibody titres for any of the viruses examined. However, only 4.2% of calves had FPT. In populations with a higher incidence of FPT, there may have been more opportunity for calves with low levels of specific antibodies to respond to vaccination. Associations between BRSV antibody titres and clinical BRD suggested maternal antibodies to BRSV may reduce the risk of BRD, and calves with low levels of maternal antibodies may produce endogenous antibodies in response to natural exposure to BRSV.
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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 | 0.001 |
| 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 | 0.000 |
| 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".