Table 4.

Direct heritability (h²) estimates for total and differential WBC and PBML subsets for SPF and non-SPF pigs^{1, 2,}

Farm	SPF				Non-SPF
Trait	Direct h2 (s.e.)	Pen effect (s.e.)	Genetic variance × 10-1	Residual variance × 10-1	Direct h2 (s.e.)	Pen effect (s.e.)	Genetic variance × 10-1	Residual variance × 10-1
WBC	0.29 (0.13)	NS	0.32	0.72	0.28 (0.11)	NS	0.21	0.55
MNL%	0.09 (0.10)	0.16 (0.06)*	0.03	2.02	0.29 (0.13)	NS	0.96	2.10
PMNL%	0.09 (0.10)	0.17 (0.06)*	0.56	4.60	0.36 (0.14)	NS	3.00	5.20
PBML subsets:
CD4+	0.78 (0.12)	NS	187	38.3	0.57 (0.14)	0.06 (0.04)*	147	94.1
CD8α+	0.35 (0.12)	NS	168	306	0.60 (0.16)	0.12 (0.05)*	215	141
CD4+CD8α+	0.34 (0.15)	NS	0.58	1.10	0.37 (0.17)	NS	0.46	0.79
CD4+CD8α-	0.82 (0.17)	NS	0.95	0.19	0.45 (0.21)	NS	0.35	0.43
CD8αβ+	0.48 (0.16)	NS	0.42	0.45	0.36 (0.17)	NS	0.32	0.56
CD11R1+ total	0.46 (0.12)	NS	0.45	0.52	0.07 (0.08)	0.34 (0.08)*	0.09	0.78
CD11R1+CD8α+	0.46 (0.13)	NS	0.11	0.13	0.31 (0.16)	NS	0.73	1.60
CD11R1+CD8α-	0.27 (0.11)	0.13 (0.06)*	0.39	0.88	0.27 (0.14)	NS	0.30	0.70
γδ+ T cells	0.46 (0.12)	0.05 (0.04)	233	279	0.30 (0.12)	NS	141	317
B cells	0.41 (0.12)	NS	0.55	0.80	0.14 (0.11)	NS	0.15	0.86
monocytes	0.26 (0.11)	0.11 (0.05)*	0.42	1.00	0.26 (0.13)	NS	0.32	0.91
CD14+	0.04 (0.09)	NS	0.08	1.90	0.48 (0.18)	NS	1.00	1.10
CD16+	0.25 (0.13)	NS	0.16	0.47	0.05 (0.09)	0.09 (0.05)*	0.04	0.83

¹Traits for which the heritability differed significantly between SPF and non-SPF farms are shown in bold (* p < 0.05). ² White blood cells expressed as no. cells × 10⁶/mL, PBML sub-sets expressed as proportion of mononuclear leucocytes and antigen density expressed as the number of antibody binding sites per cell (see Materials and Methods).