Meeting Abstract

P3.22  Tuesday, Jan. 6  Behavioral effects of contraception management; the use of porcine zona pellucida on wild horses NUNEZ, CMV*; ADELMAN, JS; MASON, C; RUBENSTEIN, DI; Princeton University; Princeton University; Foundation for Shackleford Horses, Inc.; Princeton University cmvnunez@princeton.edu

The behavioral effects of the immunocontraceptive agent porcine zona pellucida (PZP) have not been adequately studied. Important managerial decisions for several species, including the wild horse Equus caballus, have been based on this limited research. We studied 25 horses on Shackleford Banks, North Carolina to determine the effects of PZP contraception on female fidelity to the harem male. We examined two classes of females: contracepts, recipients of the PZP vaccine (n=17); and controls, females that have never received PZP (n=8). We conducted the study during the non-breeding season from December 2005 to February 2006, totaling 102.2 hours of observation. Contracepted mares changed groups more often than control mares (P = 0.03), the number of group changes increasing with the number of PZP applications (P = 0.01). In addition, contracepts visited more harem groups than did control mares (P = 0.02), and exhibited more reproductive interest (P = 0.01). Our study shows that the application of PZP has significant consequences for the social behavior of Shackleford Banks horses. In gregarious species such as the horse, PZP application may disrupt social ties among individuals and inhibit normal social functioning at the population level.