The contraceptive efficacy of a self-assembling intra-uterine device in mares

This is a report on a novel estrus (heat) suppression device based on the intrauterine marble principle, see article above for more on this. It consists of 3 oval magnets about an inch long each that when placed in the uterus will assemble themselves into a triangle an inch long on each side. As such it may be less likely to be expelled from the uterus. For more information and availability see https://www.iupod.org/.

The contraceptive efficacy of a self-assembling intra-uterine device in domestic mares
Aust Vet J. 2021 Jan 18. doi: 10.1111/avj.13055. Online ahead of print.
Authors
C J Joonè 1 , C M Gradil 2 , J A Picard 1 , J D Taylor 1 , D de Tonnerre 1 , J Cavalieri 1
Affiliations

1 College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, 4811, Australia.
2 Department of Veterinary and Animal Science, University of Massachusetts, Amherst, Massachusetts, USA.

Abstract

Objective: The primary aim of this study was to investigate the contraceptive efficacy of a self-assembling uterine device (iUPOD™) in the mare. In addition, the effects of iUPODs on oestrous cyclicity, uterine health and circulating concentrations of cortisol were evaluated.

Methods: Domestic mares underwent oestrous monitoring and artificial insemination. After subsequent ovulation, mares underwent either placement (n = 7) or sham placement (n = 7; controls) of an iUPOD device. Devices were left in place for at least 3 months. Pregnancy diagnoses were carried out 14 days post-ovulation, with any pregnancies terminated at 28 days post-ovulation. All mares underwent weekly blood sampling with or without reproductive examinations throughout the study. Towards the end of the study, multiple serum samples collected over three consecutive days were analysed for concentrations of cortisol. Endometrial biopsies were collected before artificial insemination and during the subsequent breeding season. Endometrial cytology and bacterial cultures were performed before device removal (iUPOD mares) or at the end of the study (control mares).

Results: Pregnancies were diagnosed in 0 of 7 iUPOD mares versus 7 of 7 control mares. Placement of iUPODs was associated with extended luteal phases and variable accumulations of intra-uterine fluid. Bacterial culture results suggested that the mild endometritis associated with iUPODs was sterile in six of seven mares. Short-term placement of iUPODs had no detrimental effects on endometrial architecture. Mean serum cortisol concentrations were significantly lower in iUPOD mares than control mares.

Conclusion: iUPODs represent a promising means of fertility control in the mare.