Table 11.
Component variables explaining variability in antimicrobial drugs (AMD) in preweaned dairy calves on California dairies.
| Identified components | Variation Percent (%) | Component variables | Correlation |
|---|---|---|---|
| 1. Change in the use of antimicrobial drugs following | 37.13 | Antimicrobials used on solid feed | 0.670 |
| the implementation of Veterinary Feed Directive | Antimicrobials used in water | 0.633 | |
| (VFD) in 2017 | Injectable antimicrobials | 0.629 | |
| Antimicrobials used in milk or milk replacer | 0.623 | ||
| Producer considers AMD importance in raising calves | 0.521 | ||
| Antibiotic drug costs since VFD final rule | 0.477 | ||
| Started use of alternatives to antimicrobials | 0.475 | ||
| 2. Use of diagnostics to guide treatment decision | 18.60 | Submission of calves to diagnostic labs | 0.674 |
| Use of diagnostic techniques to guide treatment | 0.491 | ||
| Frequency of animal health monitoring by veterinarian | 0.468 | ||
| 3. Source of information and decision on AMD for | 17.95 | Decision to use injectable or oral antimicrobials (Vet/Non-vet)a | 0.618 |
| feed, milk, water, oral, and injectable | Source of information on antimicrobials (Vet/ Non-vet)a | 0.582 | |
| Decision to use any antimicrobials (Vet/Non-vet)a | 0.573 | ||
| Method of estimating the drug dosage (Vet/Non-vet)a | 0.552 | ||
| Decision to treat on 1st day of illness (Vet/Non-vet)a | 0.548 | ||
| Decision on second choice antimicrobial (Vet/Non-vet)a | 0.510 | ||
| 4. Antimicrobial use protocols and records | 17.64 | Estimation treatment duration for any antimicrobial (Label/Others) | 0.613 |
| Tracked treatment information (Date/Route/Dose/None) | 0.574 | ||
| Estimation of treatment duration for injectable antimicrobials (Label/Others) | 0.506 | ||
| Tracked antibiotic withdrawal interval (Yes/No) | 0.446 | ||
| Treatment protocols components (Vaccinations/Disease Definition/Treatment) | 0.432 | ||
| Method of tracking treatments (Computer/Paper/Hutch/Memory/Chalk) | 0.436 | ||
| Keep drug inventory log (Yes/No) | 0.425 | ||
| 5. Common drugs to treat pneumonia and diarrhea | 11.06 | First choice antibiotic for treatment of Pneumonia (1-florfenicol, 2- 3rd generation cephalosporins, 3-Tulathromycin, Gamithromycin and Tildipirosin, 4-Oxytetracycline, 5-Pencillin and Ampicillin, 6-Tylosin, 7-Enrofloxacin) | 0.511 |
| 6. Calf feed management | 16.70 | Milk fed to preweaned calves (Pasteurized/ Not) | 0.642 |
The multiple factor analysis identified six components with 25 component variables with correlation >0.40 at the first three dimensions. The first three dimensions of MFA explained 21.46% of the variability (dimension 1 = 9.75%; dimension 2 = 6.56%; dimension 3 = 5.15%).
a
Varaibility due to veterinarian making decision compared to non-veterinarian.