Table 2.
Concordance correlation coefficients (CCC) and their 95% confidence interval (95% CI), and mean differences and their 95% limits of agreement, to report agreement for quantification of usage rate of antimicrobials in feed (in kilograms/100 cow-years) between quantification using feed mill invoices (reference method REF) and quantification using veterinary prescriptions (VET method) or in-person interviews of dairy producers (FARM method) by antimicrobial, category (medically important antimicrobials, MIA, or non-MIA), and totally from a sample of 101 dairy farms from Québec, Canada.
| Antimicrobial Agent(s) | REF vs. VET | REF vs. FARM | ||
|---|---|---|---|---|
| CCC (95% CI) | Mean Difference (95% Limits of Agreement) | CCC (95% CI) | Mean Difference (95% Limits of Agreement) | |
| Monensin | 0.68 (0.57, 0.76) | −0.36 (−5.69, 4.98) | 0.72 (0.61, 0.80) | −0.37 (−5.86, 5.13) |
| Lasalocid | 0.37 (0.27, 0.47) | 0.09 (−1.39, 1.57) | 0.66 (0.65, 0.67) | 0.06 (−1.08, 1.20) |
| Decoquinate | 0.41 (0.29, 0.52) | 0.07 (−0.91, 1.05) | 0.43 (0.38, 0.49) | −0.08 (−0.50, 0.33) |
| Chlortetracycline 1 | 0.73 (0.63, 0.81) | 0.03 (−0.30, 0.35) | 0.54 (0.50, 0.57) | −0.01 (−0.29, 0.26) |
| Oxytetracycline 1 | 0.38 (0.31, 0.44) | 0.06 (−0.90, 1.02) | 0.20 (0.17, 0.22) | −0.02 (−0.31, 0.27) |
| Neomycin sulfate 1 | 0.00 (−0.08, 0.07) | 0.01 (−0.28, 0.30) | 0.70 (0.69, 0.71) | 0.00 (−0.04, 0.03) |
| Streptomycin sulfate 1 | 2 | 0.00 (−0.01, 0.01) | 2 | 0.00 (0.00, 0.00) |
| Benzylpenicillin 1 | 2 | 0.00 (0.00, 0.00) | 2 | 0.00 (0.00, 0.00) |
| Sulfadiazine 1 | 2 | 0.01 (−0.14, 0.16) | 2 | 0.01 (−0.14, 0.16) |
| Sulfamethazine 1 | 0.73 (0.62, 0.80) | 0.03 (−0.28, 0.33) | 0.52 (0.51, 0.54) | 0.00 (0.00, 0.00) |
| Trimethoprim 1 | 2 | 0.00 (−0.02, 0.03) | 2 | 0.00 (0.00, 0.00) |
| Total, non-MIA | 0.63 (0.50, 0.73) | −0.19 (−6.07, 5.68) | 0.71 (0.59, 0.79) | −0.39 (−6.01, 5.23) |
| Total, MIA | 0.51 (0.38, 0.62) | 0.13 (−1.13, 1.40) | 0.51 (0.48, 0.54) | −0.05 (−0.73, 0.63) |
| Total | 0.66 (0.55, 0.76) | −0.06 (−5.85, 5.72) | 0.73 (0.63, 0.81) | −0.44 (−5.86, 4.98) |
1 Medically important antimicrobials (MIA) according to the World Health Organization [5]. 2 Antimicrobials for which both methods perfectly agreed and reported a usage of 0 kg/100 cow-years for all farms. In this case, a CCC could not be computed.