Table 2.
ICRM per 100 cow-years by high, average, and low immune response category based on EBV for AMIR for 458 Holstein dairy cows from 41 herds across Canada
| Pathogen or mastitis severity group | IRCM (per 100 cow-yrs) by AMIR categorya |
|||
|---|---|---|---|---|
| Low (n = 86) | Avg (n = 289) | High (n = 83) | All cows | |
| Escherichia coli | 6.15 | 4.53 | 4.26 | 4.77 |
| Staphylococcus aureus | 1.54 | 4.97 | 0.71 | 3.54 |
| Streptococcus spp. | 2.31 | 2.37 | 3.55 | 2.59 |
| Contagiousb | 2.31 | 6.26 | 1.42 | 4.63 |
| Environmentalc | 14.60 | 12.52 | 9.95 | 12.40 |
| Culture negative | 5.38 | 6.04 | 2.84 | 5.31 |
| Overall IRCM | 30.7 (A) | 27.9 (A) | 17.1 (B) | 26.3 |
| Mastitis severity score | ||||
| 1 | 16.14 | 15.76 (A) | 7.10 (B) | 14.17 |
| 2 | 8.45 | 10.58 | 7.81 | 9.67 |
| 3 | 6.15 | 1.94 | 2.13 | 2.72 |
IRCM values in the same row that are followed by different uppercase letters in parentheses show significant differences (P ≤ 0.05).
Contagious pathogens were Staphylococcus aureus, Streptococcus agalactiae, and Streptococcus uberis.
Environmental pathogens were Escherichia coli, Streptococcus spp. (other than S. agalactiae), Serratia spp., Citrobacter spp., Proteus spp., Salmonella spp., Pseudomonas spp., Pasteurella multocida, Corynebacterium spp., yeasts, fungi, Klebsiella spp., Staphylococcus hyicus, Prototheca spp., coagulase-negative Staphylococcus, Arcanobacterium pyogenes, Bacillus spp., non-S. aureus coagulase-positive Staphylococcus, and Enterobacter.