High interindividual and intraindividual variation of oxytocin secretion in estrous mares exposed to stallions, but no significant link to mate preferences

摘要: Oxytocin is a hormone that may not only influence reproductive mechanisms in mammals but also their social behavior, including pair bonding. We therefore tested if the concentrations of oxytocin and other hormones reveal mate preferences 13 mares estrus. Each mare was first exposed to two stallions (haphazardly selected out seven) her behavior recorded. The then returned box (i.e., no contact during time). Approximately 4.5 hours later, venous blood samples were collected every minute 30 minutes preceding exposure one previously used stallions, 6 minutes exposure, after back mare's box. procedure repeated consecutive estrus cycle, with difference each measurements. In 20 26 trials, significantly elevated stallion, without significant associations cortisol estradiol concentrations. found association between secretion previous choice situation. While concentration showed high repeatability over cycles, we considerable intraindividual differences plasma among cycles. Partially, variation could be linked time ovulation, lower which ovulated later than expected. conclusion, when teasing under experimental conditions, interindividual increase concentrations, depending on timing ovulation. However, levels seemed predictor preference.