Table 4. Effect of regions on the presence of mastitis pathogens.

Bacterial species or species groups	Hebei	Heilongjiang	Inner Mongolia	SEMa	P
S. aureus	0.4431c	0.5492	0.5674	0.0366	0.1466
E. coli	0.2629	0.227	0.3414	0.0347	0.1415
Staphylococcus spp.	0.9413	0.8746	0.9945	0.0441	0.0008*
Klebsiella spp.	0.2129	0.1587	0.3486	0.0383	0.0009*
Serratia marcescens	0.0100	0.0238	0.0027	0.0416	0.4261
S. agalactiae	0.6243	0.7921	0.9746	0.0246	< .0001*
Enterococcus spp.	0.3216	0.2302	0.4351	0.0473	0.0031*
S. uberis	0.1702	0.146	0.03466	0.0118	0.0018*
S. dysgalactiae	0.7408	0.8762	0.5289	0.0298	< .0001*
C. bovis	0.1404	0.1635	0.1586	0.0437	0.9035
A. pyogenes	0.8956	0.7079	0.5685	0.0457	< .0001*
β-lactamaseb	0.6375	0.4079	0.7966	0.0231	< .0001*

^aSEM = standard error of the mean.

^bβ-lactamase = staphylococcal β-lactamase gene.

^c0.4431 = the values in each column represent the proportion of the existence of mastitis pathogens

*P < 0.0042.