Influence of reproductive stage at PRID insertion on synchronization of estrus and ovulation in mares.
Abstract: In the present study, we investigated the effects of reproductive status, size of follicles and plasma progesterone concentrations of mares at PRID insertion on the efficacy of the treatment, estrous cycle patterns, plasma concentrations of progesterone and LH. The progesterone-releasing device (PRID) was administered intravaginally to 28 Haflinger mares for 11 days at different reproductive stages: anestrus (n=6), estrus (n=11) and diestrus (n=11). Plasma concentrations of progesterone at insertion (Day 1) of PRID differed among treatment groups (anestrus: 0.2-0.6 ng mL(-1), estrus: 0.2-0.5 and diestrus: 1.6-10.8 ng mL(-1); P<0.001). Total secretion of progesterone (area under curve (AUC)) during treatment period revealed highest values in diestrus (38.2+/-3.1 ng mL(-1)h(-1)) followed by estrus (25.1+/-2.7) and anestrus (21.0+/-0.4 ng mL(-1)h(-1); P<0.05). Progesterone area under curve (AUC) was positively correlated with initial progesterone concentrations (R=0.5; P<0.05), but it did not correlate with the interval from PRID removal to ovulation. Plasma concentrations of LH during treatment period, were significantly lower in anestrous mares (184.6+/-28.6 ng mL(-1)h(-1)) when compared to estrous and diestrous mares (349.7+/-53.3 and 370.5+/-40.3 ng mL(-1)h(-1); P<0.05). Follicular size at PRID insertion had no effects on the intervals from PRID removal to subsequent estrus and ovulation. Follicle diameters at removal of PRID were significantly correlated with the interval from coil removal to estrus (R=-0.55, P<0.05) and ovulation (R=-0.72, P<0.0004) in cyclic mares. In anestrus 0 of 6 (0%) mares, in estrus 5 of 11 (45.5%) and in diestrus 6 of 11 (54.5%) mares ovulated within a defined interval of 1 day before to 1 day after mean interval from PRID removal to ovulation. In cyclic mares, response to treatment was significantly higher when compared to anestrous mares: almost all mares responded with estrus and ovulation independent from the stage of the estrous cycle at the start of treatment. However, accuracy of synchronization was still unsatisfactory. In cyclic mares, the plasma progesterone concentrations at insertion of PRID seem to be more important for the efficacy of the treatment than the assignment to estrous cycle stages.
Publication Date: 2006-04-17 PubMed ID: 16616441DOI: 10.1016/j.anireprosci.2006.02.012Google Scholar: Lookup
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- Journal Article
Summary
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The research explores how the reproductive stage of mares at the time of Progesterone-releasing Intravaginal Device (PRID) insertion impacts estrus and ovulation synchronization. It found that the effectiveness of the treatment varies considerably based on initial progesterone levels and reproductive stage but didn’t correlate with follicle size at PRID insertion.
Objective and Approach
- The aim of this study was to determine the influence of a mare’s reproductive stage and the size of their follicles upon PRID insertion on the efficiency of estrus and ovulation synchronization.
- The researchers used 28 Haflinger mares, which were at different reproductive stages: anestrus, estrus, and diestrus when the PRID device was inserted.
- The levels of progesterone and Luteinizing Hormone (LH) in the plasma of these mares were measured throughout the treatment period. In addition, the size of the follicles at PRID insertion and removal was also recorded.
Key Findings
- Progesterone levels at PRID insertion sharply varied among treatment groups, with the highest concentration observed during diestrus.
- Progesterone secretion during the treatment was highest in the diestrus stage, followed by estrus and anestrus.
- A positive correlation was detected between initial progesterone concentrations and Progesterone Area Under Curve (AUC), but it didn’t correlate with the interval from PRID removal to ovulation.
- LH concentrations during treatment were significantly lower in anestrus mares as compared to estrus and diestrus mare.
- The size of the follicle at PRID insertion had no significant impact on the intervals from PRID removal to estrus or ovulation. However, follicle size at PRID removal was significantly associated with the time it took for the mare to enter estrus and ovulation.
- Among cyclic mares, the synchronization effectiveness was significantly higher when compared to anestrous mares.
- Despite these findings, the researchers found the accuracy of synchronization using PRID to be still unsatisfactory.
Implications
- The results suggest that the plasma progesterone concentrations at PRID insertion and the mare’s reproductive stage contribute significantly to the effectiveness of estrus and ovulation synchronization.
- This insinuates that the reproductive status of the mare at the time of PRID insertion should be considered in estrus and ovulation synchronization protocols to maximize their effectiveness.
- Further research is needed to improve the PRID-based synchronization method’s effectiveness and accuracy.
Cite This Article
APA
Handler J, Schönlieb S, Hoppen HO, Aurich C.
(2006).
Influence of reproductive stage at PRID insertion on synchronization of estrus and ovulation in mares.
Anim Reprod Sci, 97(3-4), 382-393.
https://doi.org/10.1016/j.anireprosci.2006.02.012 Publication
Researcher Affiliations
- Clinic for Obstetrics, Gynaecology and Andrology, Department of Animal Breeding and Reproduction, University of Veterinary Medicine Vienna, Veterinärplatz 1, A-1210 Vienna, Austria. johannes.handler@vu-wien.ac.at
MeSH Terms
- Administration, Intravaginal
- Animals
- Area Under Curve
- Drug Implants / administration & dosage
- Estrous Cycle / drug effects
- Estrus Synchronization / methods
- Female
- Horses / physiology
- Luteinizing Hormone / blood
- Ovarian Follicle / drug effects
- Ovulation Induction / methods
- Ovulation Induction / veterinary
- Progesterone / administration & dosage
- Progesterone / blood
Citations
This article has been cited 2 times.- Bianchi CP, Bruno S, Videla Dorna I, Rodríguez E, Aba MA. Effect of short-term artificial light and transvaginal progesterone device on first ovulation in late transitional mares. J Equine Sci 2022 Apr;33(1):1-6.
- Segabinazzi LGTM, Andrade LRP Jr, Alvarenga MA, Dell'Aqua JA Jr, Canisso IF. Use of Intravaginal Progesterone-Releasing Device Results in Similar Pregnancy Rates and Losses to Long-Acting Progesterone to Synchronize Acyclic Embryo Recipient Mares. Vet Sci 2021 Sep 10;8(9).
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