Table 4. Effects of W-Tag estrus detector application on days open, insemination frequency, and return of estrus day of Hanwoo cows in the second experiment

Item	Hanwoo cow1)		SEM	p-value
	Not use	Use
Farm (n)	5	5	-	-
Animal (head)	260	100	-	-
Days open (d)	84.8a	78.1b	1.209	< 0.001
Insemination frequency	2.52a	1.26b	0.266	< 0.001
Return of estrus (d)	79.1a	70.9b	0.648	< 0.001

Not use, cows without estrus detector; Use, cows with estrus detector.
Means in the same row with different superscripts differ (p < 0.05).