Table 4.

Linear mixed models describing the difference in gene expression in milk somatic cells before and after experimental challenge

Gene	All quarters 1 h		Neighboring quarters			Infected quarters
	before inoculation a		12 h after inoculation			12 h after inoculation
	(n = 15 b )		(n = 8)			(n = 7 b )
	β 0 c	SE d	β c	SE d	P -value	β c	SE d	P -value
ACTB	0.27	0.07	-0.06	0.08	0.46	0.10	0.09	0.27
B2M	0.04	0.06	0.15	0.07	<0.05	0.41	0.07	<0.01
CXCR1	-1.30	0.15	0.94	0.26	<0.01	1.71	0.27	<0.01
H2A	-0.04	0.06	0.17	0.07	<0.05	-0.21	0.07	<0.01
HPRT1	-0.08	0.05	-0.03	0.07	0.66	-0.31	0.07	<0.01
RPS15A	-0.10	0.10	-0.07	0.12	0.59	-0.06	0.13	0.62
SDHA	-0.13	0.05	0.04	0.08	0.67	-0.22	0.09	<0.05
UBC	-0.17	0.05	0.13	0.08	0.10	-0.03	0.08	0.67
YWHAZ	-0.13	0.08	0.05	0.09	0.61	0.28	0.09	<0.01

^aTwo quarters of 8 dairy heifers were inoculated with PBS or Staphylococcus chromogenes.

^bTwo samples showed insufficient cDNA integrity and were therefore removed from the dataset.

^cRegression coefficient.

^dStandard error.

Heifer and quarter were added as random effect to correct for clustering of quarters within cows and two observations per quarter, respectively.