Ovarian function and pregnancy outcome in pony mares following immunocontraception with native and recombinant porcine zona pellucida vaccines.
Abstract: Few studies have investigated ovarian function in the mare undergoing porcine zona pellucida (pZP) immunocontraception despite reported ovarian dysfunction in other species. Objective: This study aimed to describe ovarian function and oestrous cyclicity in pony mares following treatment with either the conventional pZP vaccine or a novel recombinant form of the vaccine derived from porcine ZP3 and ZP4 (reZP). In addition, the contraceptive efficacy of pZP vs. reZP was assessed. Methods: Blinded, randomised, prospective clinical trial. Methods: Mares (n = 21) were randomised into 3 groups of 7: Group I received the pZP vaccine, with a booster 5 weeks later; Group II received the reZP vaccine, with a booster 5 weeks later; and Group III (controls) received 2 treatments, 5 weeks apart, of saline and adjuvant alone. Mares underwent weekly monitoring via transrectal palpation and ultrasound examination of the reproductive tract, with daily monitoring during oestrus. Data were collected over a 24 week period coinciding with the physiological breeding season; treatments commenced in Week 4. Serum samples were obtained for antibody titres and ovarian steroid level analyses at 7 day intervals. Cycling mares were bred via fresh semen artificial inseminations over a maximum of 2 consecutive oestrous cycles, commencing 5 weeks post booster vaccination. Results: Control mares cycled throughout the trial. After treatment, 6 of 7 pZP mares (86%) and one reZP mare (14%) had an extended anoestrus that correlated with basal serum oestradiol and progesterone levels. All mares resumed cyclicity by 10 months post treatment. Pregnancies were diagnosed in all controls, 4 reZP- (57%) and none of the pZP-immunised mares. Conclusions: The current study demonstrates the reversible suppression of ovarian function in pony mares following treatment with pZP. The effect of the reZP vaccine on pregnancy outcome requires further investigation.
© 2015 EVJ Ltd.
Publication Date: 2016-02-29 PubMed ID: 26708619DOI: 10.1111/evj.12557Google Scholar: Lookup
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- Journal Article
- Randomized Controlled Trial
Summary
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The research paper investigates the effects of porcine zona pellucida (pZP) immunocontraception on ovarian function in pony mares. It also explores the efficiency of a conventional pZP vaccine and a new recombinant form, derived from porcine ZP3 and ZP4 (reZP), in suppressing pregnancies.
Objective and Methodology
- The study’s main goal was to examine ovarian function and oestrous cyclicity in pony mares after immunization with pZP or the reZP vaccine.
- The researchers conducted a blinded, randomised, prospective clinical trial involving 21 mares divided into three groups.
- The first group received pZP and a booster 5 weeks later, the second group received the reZP vaccine followed by a booster, while the third group (controls) were given saline and adjuvant treatments 5 weeks apart.
- The health of these mares was monitored weekly through transrectal palpation and ultrasound examination of their reproductive tracts. Serum samples were also collected for antibody titres and ovarian steroid level analysis at 7-day intervals.
- All the mares that were still cycling were bred via artificial insemination during two consecutive oestrous cycles, beginning 5 weeks after the booster vaccination.
Findings
- All the control mares continued to cycle throughout the trial.
- Five out of seven mares in the pZP group and one mare in the reZP group experienced an extended period of anoestrus, which corresponded with basal serum oestradiol and progesterone levels.
- All the mares eventually resumed cyclicity by 10 months post treatment.
- All control mares were diagnosed pregnant, compared to four in the reZP group and none in the pZP group.
Conclusions
- The study concludes that pZP immunocontraception can cause a reversible suppression of ovarian function in pony mares. This discovery aligns with earlier findings of pZP’s contraceptive effect in other species.
- The recombinant reZP vaccine showed moderately effective contraceptive results, but its impact on pregnancy outcome needs further exploration.
Cite This Article
APA
Joonè CJ, Bertschinger HJ, Gupta SK, Fosgate GT, Arukha AP, Minhas V, Dieterman E, Schulman ML.
(2016).
Ovarian function and pregnancy outcome in pony mares following immunocontraception with native and recombinant porcine zona pellucida vaccines.
Equine Vet J, 49(2), 189-195.
https://doi.org/10.1111/evj.12557 Publication
Researcher Affiliations
- Section of Reproduction, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
- Section of Reproduction, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
- Reproductive Cell Biology Laboratory, National Institute of Immunology, New Delhi, India.
- Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
- Reproductive Cell Biology Laboratory, National Institute of Immunology, New Delhi, India.
- Reproductive Cell Biology Laboratory, National Institute of Immunology, New Delhi, India.
- University of Utrecht, The Netherlands.
- Section of Reproduction, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
MeSH Terms
- Animals
- Antibodies / blood
- Contraception, Immunologic / veterinary
- Estradiol / blood
- Female
- Ovary / physiology
- Pregnancy
- Pregnancy Outcome
- Pregnancy, Animal
- Progesterone / blood
- Swine
- Vaccines, Contraceptive / immunology
- Zona Pellucida / immunology
Citations
This article has been cited 5 times.- Asa CS, Moresco A. Fertility Control in Wildlife: Review of Current Status, Including Novel and Future Technologies. Adv Exp Med Biol 2026;16:605-645.
- Schulman ML, Hayes NK, Wilson TA, Grewar JD. Immunocontraceptive Efficacy of Native Porcine Zona Pellucida (pZP) Treatment of Nevada's Virginia Range Free-Roaming Horse Population. Vaccines (Basel) 2024 Jan 18;12(1).
- French H, Segabinazzi L, Middlebrooks B, Peterson E, Schulman M, Roth R, Crampton M, Conan A, Marchi S, Gilbert T, Knobel D, Bertschinger H. Efficacy and Safety of Native and Recombinant Zona Pellucida Immunocontraceptive Vaccines Formulated with Non-Freund's Adjuvants in Donkeys. Vaccines (Basel) 2022 Nov 24;10(12).
- Aurich C, Kaps M. Suppression of reproductive behaviour and gonadal function in female horses-An update. Reprod Domest Anim 2022 Sep;57 Suppl 4(Suppl 4):4-12.
- Tatematsu KI, Ikeda M, Wakabayashi Y, Yamamura T, Kikuchi K, Noguchi J, Sezutsu H. Silkworm recombinant bovine zona pellucida protein 4 (bZP4) as a potential female immunocontraceptive antigen; impaired sperm-oocyte interaction and ovarian dysfunction. J Reprod Dev 2021 Dec 14;67(6):402-406.
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