Table 1. Table of variables from NBRDI data.

Variable	Variable name	Interpretation
Y	Bovine Respiratory Disease (BRD)
	no	No BRD diagnosed between day 0 a and day 50
	yes	BRD diagnosed between day 0 and day 50
A	Bovine Viral Diarrhea Virus (BVDV) induction
	no	Seronegative to BVDV at induction, no BVDV exposure prior to induction at the feedlotb
	yes	Seropositive to BVDV at induction, BVDV exposure prior to arrival at the feedlot
X1	Age	Age at induction at the feedlot
X2	Weight	Weight at induction at the feedlot
X3	Mix History (collapsed version)
	no, high	No mixing before day -27 and ≥4 groupsc defined on day -28 forming cohort
	no, low	No mixing before day -27 and <4 groups defined on day -28 forming cohort
	yes, high	Mixing before day -27 and ≥4 groups defined on day -28 forming cohort
	yes, low	Mixing before day -27 and <4 groups defined on day -28 forming cohort
X4	Persistently Infected (PI) Group
	no BVDV in cohortd	No BVDV in the cohort
	PI animal before cohort	PI animals in the groups defined on day -28 and in cohort
	PI animal in cohort	PI animals in the cohort
	TI but no PI in cohort	Only transiently infected animals in the cohort
X5	BVDV vaccination
	no	No Pestigard™ vaccine administered prior to day -14
	yes	Pestigard™ vaccine administered prior to day -14
Ui	Feedlot	Feedlot Identifier

^a Day 0 is the date of induction (processing) which was on or close to the day of arrival at the feedlot; day -27 is 27 days before day 0

^b Feedlot is an intensive commercial unit in a single location involved in the finishing stages of beef production

^c Group is an identifier used for animals within a cohort that were together on a given day prior to induction

^d Cohort comprises all study animals grouped together in a pen following their animal-level induction, and cohorts were nested within feedlots