TABLE 2.
Mean percents Salmonella and MDR Salmonella prevalence by region
| Sample group and parameter | Value for:a |
P |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| A |
B |
C |
D |
Overall |
||||||||
| Not MDR | MDR | Not MDR | MDR | Not MDR | MDR | Not MDR | MDR | Not MDR | MDR | Not MDR | MDR | |
| Hide (cull) | ||||||||||||
| % Salmonella | 80.4C | 7.6AB | 80.9C | 11.2AB | 91.1C | 1.9A | 38.9D | 46.0B | 72.9 | 16.7 | 0.0004b | 0.0008b |
| 95% CI | 66.8-93.9 | 0.5-14.8 | 70.5-91.4 | 3.3-19.1 | 83.6-98.6 | -0.3-4.3 | 19.4-58.4 | 20.9-71.0 | 63.7-82.1 | 8.3-25.1 | ||
| Median % prevalence | 81.6 | 3.7 | 80.0 | 10.0 | 94.8 | 1.6 | 35.4 | 43.7 | 80.6 | 6.9 | ||
| Simpson's ID | 0.41 | 0.5 | 0.1 | 0.5 | 0.4 | 0.0785c | ||||||
| 95% CI | 0.19-0.64 | 0.26-0.74 | −0.18-0.38 | 0.33-0.59 | 0.29-0.49 | |||||||
| Hide (fed) | ||||||||||||
| % Salmonella | 81.3 | 18.7d | 79.2 | 2.9 | 98.4 | 0.0 | 69.1 | 17.6 | 82.0 | 9.8 | ||
| 95% CI | 62.6-101.4 | −5.7-25.3 | ||||||||||
| Preevisceration (cull) | ||||||||||||
| % Salmonella | 45.8CD | 6.4AB | 58.3D | 8.9A | 25.6C | 1.3B | 24.2C | 30.1A | 38.5 | 11.7 | 0.0113c | 0.0026b |
| 95% CI | 26.6-65.0 | −1.1-13.9 | 35.9-80.6 | 2.8-15.1 | 15.0-36.1 | −0.29-2.9 | 4.5-43.9 | 1.9-58.3 | 29.3-47.7 | 4.4-19.0 | ||
| Median % prevalence | 45.8 | 2.1 | 55.2 | 6.8 | 26.5 | 0.0 | 9.5 | 18.5 | 37.9 | 4.8 | ||
| Preevisceration (fed) | ||||||||||||
| % Salmonella | 53.8 | 14.6d | 34.6 | 2 | 60.2 | 0.0 | 14.4 | 4.3 | 40.8 | 5.2 | ||
| 95% CI | 7.9-73.6 | −5.1-15.6 | ||||||||||
| Postintervention (cull) | ||||||||||||
| % Salmonella | 0.54 | 0.8 | 0.27 | 0.14 | 0.14 | 0.0 | 0.9 | 0.4 | 0.5 | 0.3 | 0.8791b | 0.4525b |
| 95% CI | −0.42-1.5 | −0.75-2.3 | −0.15-0.7 | −0.19-0.46 | −0.19-0.46 | 0.0 | −1.3-3.1 | −0.26-1.1 | −0.04-0.98 | −0.03-0.70 | ||
Common uppercase superscripts (A and B, MDR Salmonella, and C and D, non-MDR Salmonella) indicate values that are not significantly different (P < 0.05).
Comparisons of median prevalence values were made using the Kruskal-Wallis test for nonparametric data and Dunn's multiple-comparison posttest.
Comparisons of mean prevalence or diversity values (normally distributed data sets) were made using a one-way ANOVA and Bonferroni's multiple-comparison posttest.
Fed cattle MDR Salmonella prevalence values for hides and carcasses in region A (measured in summer only) were reflective of cull cattle MDR Salmonella prevalence values for the same region and season. MDR Salmonella prevalence values for cull cattle hides and preevisceration carcasses in this region and season were as follows: for hide samples, 4.2% for day 1 and 20% for day 2, and for preevisceration carcass samples, 2.5% for day 1 and 47.9% for day 2. These results demonstrate the wide range in prevalence values that can be observed from one sample day or time point to the next.