5alpha-Androstenone concentrations in sow plasma during the estrous cycle

Plasma concentrations of 5alpha-androst-16-en-3-one (5alpha-androstenone), the steroid responsible for boar taint, were measured by radioimmuno-assay in eight sows during the estrous cycle. The steroid concentrations ranged from a low of approximately 500 pg/ml to a high of 2.2 ng/ml during the estrous cycle. Noticeable features in the hormone profile of sows sampled, were the decline in the period preceding estrus, comparatively low levels at estrus and an increase post-estrous. Changes in hormone concentrations over the estrous cycle were significant (P<.05). The timing of the changes in 5alpha-androstenone concentrations during the period preceding estrus among the sows studied was not consistent. The physiological significance of the changes in 5alpha-androstenone concentrations during the period preceding estrus among the sows studied was not consistent. The physiological significance of these changes in 5alpha-androstenone concentration seen during the estrous cycle is not clear. Any bearing these changes may have on the malefemale sexual relationship in pigs needs to be further investigated in view of the known pheromonal function of 5alpha-androstenone.