Table 4.

Genetic trends for sow exploratory behavior.

Trait (criterion)	Parity	Old-type sowsa	Modern-type sows	ΔG (SEΔG)b	Pr > |t| H0: ΔG = 0c
Rooting (#)	1	8	6	−4 (3)	0.46
	2	7	2	−10 (3)	0.0004
Rooting (min)	1	10.3	4.8	−11.0 (3.5)	0.16
	2	11.4	2.4	−18.0 (3.3)	0.001

^aLeast square means estimated from data analyzed during the first 6 h after onset of farrowing.

^bGenetic trend estimated from 1977 to 1998: ΔG = 2 × (modern-type mean—old-type mean) and SEΔG = 2 × SE (modern-type mean—old-type mean).

^cProbability associated with the null hypothesis (H0): ΔG = 0 (P-value).