1997 Nebraska Swine Report

Cover Art Caption: Odor emission from swine facilities is a major issue for the pork industry. Here, air samples are taken to determine the impact of reducing dietary crude protein concentration through the use of crystalline amino acids on odor emission into building air. The effects of type of housing (stalls versus pens) and method of heat detection (fence-line boar exposure conducted in-place versus after reloca-tion 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 < .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 < .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.