Genetic analysis of disease resilience of wean-to-finish pigs under a natural disease challenge model using reaction norms

Table 3 Comparison of slope genetic variance and reaction norm models for analysis of average daily gain (ADG, g) and treatment rate (TRT) in the challenge nursery (cNur), finisher (Fin) and across the nursery and finisher (All) for six challenge loads based on clinical disease traits or growth rate

Trait	CL using clinical disease traits			CL using growth rate			P-value vs. no RN
Trait	NurCLc	FinCLc	CLc	NurCLg	FinCLg	CLg	P-value vs. no RN
Linear RN
cNurADG	400 (500)	500 (300)	500 (300)	0	2200 (400)	2000 (4000)	< 0.0001
FinADG	1100 (600)	200 (300)	1200 (500)	200 (400)	0	0	0.004
cNurTRT	NA	0.01 (0.02)	0.10 (0.04)	0	0.07 (0.03)	0.09 (0.03)	0.03
AllTRT	0	0	0.21 (0.05)	0.016 (0.03)	0	0.11 (0.04)	0.001

Trait	CL using clinical disease traits			CL using growth rate			P-value vs. linear RN
	NurCLc	FinCLc	CLc	NurCLg	FinCLg	CLg
Cubic RN
cNurADG	400 (500)	240 (300)	600 (300)	160 (300)	2500 (600)	2000 (500)	0.35
FinADG	1200 (700)	200 (200)	1600 (500)	500 (400)	0	0	0.001
cNurTRT	0.24 (0.05)	NA	0.08 (0.04)	0	0.07 (0.03)	0.09 (0.03)	0.04
AllTRT	0	0	0.27 (0.06)	0.015 (0.03)	0	0.11 (0.04)	0.0003

Only one corresponding CL was fitted as fixed effect in the linear and cubic spline reaction norm model. CL: challenge load; RN: reaction norm; NurCLc: challenge load derived from the clinical disease traits in the challenge nursery; FinCLc: challenge load derived from the clinical disease traits in early finisher; CLc: weighted challenge load of NurCLc and FinCLc; NurCLg: challenge load derived from the growth rate in the challenge nursery; FinCLg: challenge load derived from the growth rate in early finisher; CLg: weighted challenge load of NurCLg and FinCLg; P-value for cNurADG was based on FinCLg and P-values for FinADG, cNurTRT, and AllTRT were based on CLc because CLc was the best CL for these three traits. P-values for the linear model were based on comparison of the linear reaction norm model with the standard model without random slope term. P-values for the cubic spline model were based on comparison of the cubic spline reaction norm model with the linear reaction norm model. cNurADG: growth rate in the challenge nursery; FinADG: growth rate in the finisher; cNurTRT: medical treatment rate in the challenge nursery; AllTRT: medical treatment rate across the challenge nursery and finisher; figures in italic characters indicate the greatest genetic slope variance for that trait

ISSN: 1297-9686