Dwane R. Zimmerman, Tom McGargill, Norm Rohda and Jeff Hall
Summary and Implications
Fence-line boar exposure (FBE) and physical boar exposure (PBE), each with durations of 10 min or 4 h, were evaluated for their ability to trigger puberty in gilts. Gilts provided PBE attained puberty 11.8 days earlier than gilts provided FBE. Duration of boar contact was without effect. Earlier age at first estrus resulted, in large part, from a more rapid pubertal response after initiation of boar exposure (BE). The mean interval from initiation of BE to pubertal estrus was 13.5 days for PBE gilts and 24.8 days for FBE gilts. Fence-line boar exposure stimulates earlier puberty in gilts (shown in previous studies), but is less effective than PBE for triggering a rapid pubertal response in gilts. Physical boar exposure is required to achieve the maximal pubertal response to boar exposure when applied daily for limited periods (4 h or less) to gilts nearing onset of puberty.