Table 1. Characteristics of seven California dairy herds enrolled in a cross-sectional study to survey for Salmonella sp. fecal shedding in a random sample of cull dairy cows.
| Herd | Mean milking herd size (SE) | RHA,a Kg (SE) | Herd breedb distribution, (%) | Collected samples breed distribution, (%) | Herd percent culled per month, % (SE) | Culling times per month | Facility designc |
|---|---|---|---|---|---|---|---|
| 1 | 3,763 (180) | 10,768 (451) | H (45%), J (55%) | H (63%), J (37%) | 2.66 (0.04) | 1 to 2 | FS |
| 2 | 2,810 (29) | 11,546 (111) | H (100%) | H (100%) | 3.13 (0.17) | 4 to 5 | FS |
| 3 | 3,050 (102) | 8,217 (440) | J (100%) | J (100%) | 3.48 (0.2) | 1 to 4 | DL |
| 4 | 5,600 (141) | 13,467 (109) | H (95%), J (5%) | H (100%) | 2.83 (0.32) | 1 to 4 | FS |
| 5 | 2,633 (113) | 10,878 (26) | H (100%) | H (100%) | 2.37 (0.01) | 1 | DL |
| 6 | 839 (39) | 12,500 (228) | H (100%) | H (100%) | 8.82 (0.29) | 1 | FS |
| 7 | 1,606 (37) | 14,559 (367) | H (100%) | H (100%) | 2.4 (0.07) | 1 | DL |
| All | 3,059 (1,386) | 10,297 (202) | 3.27 (0.13) |
Notes:
a
Rolling herd average defined as the mean milk produced per milking cow in the herd in 365 days.
b
(H), Holstein and (J), Jersey breeds.
c
Facility design: (FS), freestall and (DL), drylot.