Table 5. Farrowing interval in groups of sows

Classification	Farrowing interval(days)
Classification	Mean±SD
Small farm	158.65±11.67^a
Large farm	151.41±4.00^b
Spring	155.02±5.18^ab
Summer	154.88±6.40^ab
Fall	150.20±12.30^b
Winter	157.12±8.44^a
Average	154.30±8.68

Values with different superscripts are significantly different (p<0.05).