Table 9.

For calves treated for BRD after 13DOF (n = 65), associations between deep nasopharyngeal culture and susceptibility (C/S) test results at 13DOF and likelihood of corresponding C/S results for calf at time of BRD treatment.

			95% CI
Risk factor: calf culture positive at 13DOF	Outcome: calf C/S result at BRD treatment	OR	Lower	Upper	p-value
M. haemolytica	M. haemolytica	2.8	0.7	11	0.15
P. multocida	P. multocida	4.4	1.3	15	0.019
H. somni	H. somni	2.5	0.8	8.3	0.13
Any bacteria with AMR	Any bacteria with AMR	4.9	1.1	21	0.036
Any bacteria with macrolide resistance*	Any bacteria with macrolide resistance	9.8	1.2	77	0.030
Any bacteria with tetracycline resistance*	Any bacteria with tetracycline resistance	2.9	1.8	4.6	< 0.001

Analysis accounted for year and injectable metaphylaxis administered, and DOF at time of BRD treatment, and adjust for clustering by pen-cohort unless otherwise noted (N = 16 pens). OR, odds ratio; 95% CI, 95% confidence interval. *Unconditional GEE logistic regression reported: no calves with BRD from 2021/oxytetracycline cohorts had macrolide resistance at time of BRD treatment and no calves from 2021/tulathromycin cohorts had tetracycline resistance at time of BRD treatment. See details for other fixed effects and measures of model fit in Supplementary Table S9.