TABLE 1.

Study herd characteristics

Herd and ID codeaNo. of lactating cowsBreedHusbandryRHAbRisk assessment scorec% Fecal culture positived
Noninfected herds
    M68HolsteinTie stall26,861290.0
    N43HolsteinStanchion23,000690.0
    O48HolsteinTie stall26,500400.0
    P50HolsteinTie stall23,500460.0
    Q37HolsteinStanchion22,000740.0
    R56HolsteinStanchion22,000780.0
    S57HolsteinStanchion25,300530.0
M. paratuberculosis-infected herds
    B404HolsteinFreestall24,0603527.5C
    C88HolsteinStanchion24,8354314.8A
    E308HolsteinFreestall23,9004822.7B
    F261JerseyStanchion9,135349.2A
    G203HolsteinFreestall21,8103432.5C
    J750HolsteinFreestall26,3502120.8B
    K80HolsteinStanchion22,820269.5A
  • a ID, identification. Noninfected herds were all in Minnesota; infected herds were all in Wisconsin.

  • b RHA, rolling herd average in pounds of milk per cow per year.

  • c Risk assessment score based on Johne's disease assessment forms used in Minnesota. The Minnesota and Wisconsin herds were scored by different veterinarians.

  • d Based on isolation of M. paratuberculosis by any one of three laboratories on aliquots of the same fecal sample collected at the same time as were the blood and milk samples. Superscript capital letters denote significant differences among herds; different letters indicate significant differences (P < 0.05).