Table 1. Seasonal difference of bovine coronavirus infection rate.

Season (Month)	Positive rate of bovine coronavirus (No. of positive/No. of inspections)
	All cattle	Respiratory symptoms
Early spring (Mar.)	36.2% (17/47)	50.0% (8/16)
Late spring (Apr., May)	5.2% (3/57)	6.6% (3/45)
Summer (Jun., Jul., Aug.)	4.7% (1/21)	4.7% (1/21)
Early autumn (Sep., Oct.)	1.8% (1/55)	2.0% (1/49)
Late autumn (Nov.)	100% (13/13)	100% (6/6)
Winter (Dec., Jan., Feb.)	19.0% (50/262)	28.6% (39/136)
Total	18.6% (85/455)	21.2% (58/273)