Table 1.

List of variables included in GLMSELECT procedure to produce final multivariate model

Variable	Type	Description
Production	Binary	Organic or Conventional
State	Nominal	NY, OR, or WI
Herd size	Ordinal	< 100, 100 to 200, or > 200
Parity	Continuous	The average lactation of all lactating cows at the time of the survey
Average yield	Continuous	Average annual milk production per cow
Calf housing	Nominal	Always housed in individual pens or areas; sometimes housed in groups or with contact to cows; always housed in groups or with contact to cows
Description of calving area	Nominal	Dedicated calving area; area shared with lactating cows; or area sometimes shared with sick cows
Heifer and cow contact on pasture	Nominal	Heifers grazing a pasture with or after the cows; before the cows; or heifers and cows do not graze the same pasture
Jersey	Binary	Mostly Jersey or not mostly Jersey herd
Johne’s procedures	Nominal	Procedures for MAP-positive cows: cull after calving or dry off; cull immediately; keep; never observed clinical Johne’s disease
Johne’s program	Binary	Participation in Johne’s program
Open farm	Binary	Some or no entering animals
Seasonality sine	Continuous	$$\mathrm{Sin}\left(2\mathrm{\pi }\frac{\mathrm{Day}}{365}\right)$$ , where day is a continuous variable from 1 to 365
Seasonality cosine	Continuous	$$\mathrm{Cos}\left(2\mathrm{\pi }\frac{\mathrm{Day}}{365}\right)$$ , where day is a continuous variable from 1 to 365
Source of drinking water	Nominal	Primary source of drinking water for 60 days prior to survey: well; municipal water; or surface water
Spreading manure	Binary	Manure spreading on pasture or fields that will be consumed by animals
Written plan for Johne’s disease	Binary	Written herd plan for managing Johne’s disease