Is Physical Boar Exposure Required for Accurate Detection of Estrus in Gilts?

Accuracy of estrus detection in response to physical (PBE) vs fenceline (FBE) boar exposure was evaluated in 40 gilts during two successive estrous periods. Gilts heat checked with FBE expressed shorter estrous periods (.6 day) than PBE gilts. Estrus was detected within five minutes of boar exposure in 100 percent of gilts on both treatments except for PBE gilts on the first day of estrus. The first day of estrus was expressed after five minutes of boar exposure in 16.2 percent of PBE vs 0 percent of FBE gilts. The PBE gilts may be near the beginning of estrus. They are unresponsive to limited (15 min) FBE and slow to respond to PBE. Fertility was not compared in this study, but inseminations timed 12 to 24 hours after detection of estrus in these gilts (gilts not detected with FBE and slow to respond to PBE on their first day of estrus) will be too late to result in high fertility. Ovulation will occur or be in progress in these gilts at the time of insemination. Therefore, heat-detection with physical boar exposure rather than fence-line boar exposure is recommended to achieve proper timing of insemination and high fertility in gilts

Is Physical Boar Exposure Required for Accurate Detection of Estrus in Gilts?

Accuracy of estrus detection in response to physical (PBE) vs fenceline (FBE) boar exposure was evaluated in 40 gilts during two successive estrous periods. Gilts heat checked with FBE expressed shorter estrous periods (.6 day) than PBE gilts. Estrus was detected within five minutes of boar exposure in 100 percent of gilts on both treatments except for PBE gilts on the first day of estrus. The first day of estrus was expressed after five minutes of boar exposure in 16.2 percent of PBE vs 0 percent of FBE gilts. The PBE gilts may be near the beginning of estrus. They are unresponsive to limited (15 min) FBE and slow to respond to PBE. Fertility was not compared in this study, but inseminations timed 12 to 24 hours after detection of estrus in these gilts (gilts not detected with FBE and slow to respond to PBE on their first day of estrus) will be too late to result in high fertility. Ovulation will occur or be in progress in these gilts at the time of insemination. Therefore, heat-detection with physical boar exposure rather than fence-line boar exposure is recommended to achieve proper timing of insemination and high fertility in gilts

Method of Detection, Not Type of Housing, Affects Accuracy and Rapidity of Estrus Detection in Gilts

The effects of type of housing (stalls versus pens) and method of heat detection (fence-line boar exposure conducted in-place versus after relocation of gilts to the boar room) on the accuracy and rapidity of estrus detection were evaluated in 24 gilts during two successive estrous periods. Gilts relocated to the boar room showed a higher rate of estrus detection and a more rapid estrous response (P \u3c .05) to fence-line boar exposure (81% and 1.7 min, respectively) than gilts provided fence-line boar exposure in-place (67.5% and 2.3 min, respectively). Gilts housed in stalls and pens showed similar rates of estrus detection (68% and 67%, respectively) but the estrous response to fence-line boar exposure tended to occur more rapidly in gilts housed in pens than in stalls (2.0 versus 2.5 min, P \u3c .1). Gilts not detected in estrus with fence-line boar exposure were slow to respond to a later heat check with physical boar exposure (3.8 min). Physical boar exposure is required for highly accurate heat detection in gilts. For optimal results, boar stimulation should be provided in an environment removed from the residence of the gilts