Sexual arousal intensity modulates copulatory behavior and semen quality in Arabian stallions: Effects of age, origin, and collection method.
Abstract: Stallion sexual behavior during semen collection can be influenced by multiple factors, yet the role of sexual arousal intensity remains underexplored. Understanding how arousal modulates behavioral and physiological reproductive traits is essential for improving artificial insemination (AI) efficiency and semen quality. This study aimed to evaluate the effects of sexual arousal intensity, age, origin, and semen collection method on stallion sexual behavior and the quality of fresh and frozen semen. Unassigned: Thirteen Arabian stallions (7 Tunisian, 6 foreign parentage) aged 6-20 years (total ejaculates = 49) were assessed during semen collection using either a dummy or an estrous mare. Sexual arousal intensity was scored on a four-point scale (- to +++). Behavioral responses, mounting and erection parameters, and semen traits were recorded. Fresh semen was evaluated for volume, motility, concentration, and morphology; frozen semen was assessed for motility, viability, membrane integrity, and abnormalities. Data were analyzed using multifactorial analysis of variance with significance at p < 0.05. Unassigned: High arousal (+++) increased vocalizations, anogenital sniffing, and Flehmen responses (p < 0.05) but prolonged preparation time (p = 0.05). Low arousal (-/+) prolonged full erection duration (p < 0.01) and improved sperm motility in fresh and frozen semen (p < 0.01). Stallions of foreign origin exhibited higher fresh semen motility (p < 0.01) but required longer preparation and collection times (p < 0.05). The estrous mare method improved fresh semen motility and concentration (p < 0.05) but did not affect frozen semen traits. Younger stallions produced larger semen volumes, but had higher abnormal sperm counts in fresh samples, whereas older stallions showed more abnormalities post-freezing (p < 0.01). Unassigned: Sexual arousal intensity significantly modulates both behavioral and semen quality parameters in stallions. Lower arousal is associated with prolonged erection and superior sperm motility, suggesting dissociation between behavioral excitement and physiological semen traits. Collection from an estrous mare can enhance fresh semen motility, though the dummy remains safer for handlers. These findings highlight the importance of tailoring semen collection protocols to individual stallion profiles to optimize AI outcomes.
Copyright: © Najjar, et al.
Publication Date: 2025-09-06 PubMed ID: 41113212PubMed Central: PMC12535463DOI: 10.14202/vetworld.2025.2615-2625Google Scholar: Lookup
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- Journal Article
- Age Factors
- Animal Species
- Animal Study
- Arabian Horses
- Assisted Reproductive Techniques
- Behavior
- Breed Differences
- Equine Health
- Equine Medicine
- Equine Science
- Fertility
- Reproduction
- Reproductive Technology
- Semen Analysis
- Semen Preservation
- Sexual Behavior
- Stallion
- Statistical Analysis
- Veterinary Research
- Veterinary Science
Summary
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Overview
- This study investigated how the intensity of sexual arousal in Arabian stallions affects their mating behavior and the quality of their semen, considering factors like age, origin, and the method used for semen collection.
- The research aimed to optimize artificial insemination (AI) outcomes by identifying how behavioral and physiological traits are influenced during semen collection.
Objectives and Background
- To explore the relationship between sexual arousal intensity and both behavioral and semen quality traits in stallions.
- To assess how factors such as age, geographic origin, and the semen collection method (dummy versus estrous mare) impact these traits.
- Artificial insemination (AI) success depends heavily on semen quality and stallion behavior during semen collection, yet the role of sexual arousal intensity remained underexplored prior to this study.
Methodology
- Subjects: 13 Arabian stallions aged 6-20 years; 7 from Tunisia and 6 of foreign parentage.
- Total ejaculates collected: 49 across stallions.
- Sexual arousal intensity was scored on a four-point scale ranging from low (-) to high (+++).
- Two semen collection methods used:
- Dummy mare (artificial mount)
- Estrous mare (live mare in heat)
- Behavioral observations included:
- Vocalizations
- Anogenital sniffing
- Flehmen response (lip-curling to detect pheromones)
- Preparation and erection times
- Semen quality assessment:
- Fresh semen: volume, motility, concentration, and morphology
- Frozen semen: motility, viability, membrane integrity, and abnormalities
- Data analyzed using multifactorial ANOVA with significance at p < 0.05
Key Findings – Behavioral Responses
- Higher sexual arousal (+++) led to:
- Increased vocalizations
- More anogenital sniffing
- More frequent Flehmen responses
- Longer preparation time before mounting (p = 0.05)
- Lower sexual arousal (-/+) resulted in:
- Longer duration of full erection (p < 0.01)
- Indication that intense behavioral excitement does not necessarily correlate with prolonged erection
Key Findings – Semen Quality
- Lower arousal (-/+) correlated with:
- Improved sperm motility in both fresh and frozen semen samples (p < 0.01)
- Suggesting a dissociation between sexual excitement and semen physiological quality
- Stallion origin differences:
- Foreign-origin stallions showed higher motility in fresh semen (p < 0.01)
- These stallions required longer preparation and collection times (p < 0.05)
- Collection method effects:
- Using an estrous mare improved fresh semen motility and concentration (p < 0.05)
- No significant effect on frozen semen traits
- Dummy method considered safer for handlers despite fewer motility benefits
- Age-related findings:
- Younger stallions produced larger semen volumes but had higher abnormal sperm counts in fresh semen
- Older stallions displayed more sperm abnormalities after freezing (p < 0.01)
Interpretations and Implications
- Sexual arousal intensity plays a significant role in both behavioral patterns and semen quality in Arabian stallions.
- A lower intensity of arousal may be beneficial for semen motility and quality, which is crucial for AI success.
- Behavioral excitement and physiological semen traits can be dissociated, implying that more vigorous sexual behavior does not guarantee better semen quality.
- Origin and age of stallions affect their reproductive performance, suggesting the need for tailored semen collection strategies.
- Using an estrous mare improves certain semen parameters but poses more risk to handlers compared to using a dummy mare.
- Customized approaches to semen collection based on individual stallion profiles and arousal levels could enhance the effectiveness of artificial insemination programs.
Conclusion
- The study highlights the importance of monitoring and modulating sexual arousal intensity during semen collection to optimize both stallion behavior and semen quality.
- Adjustments in collection methods and management based on stallion age, origin, and arousal level can improve AI outcomes in Arabian horses.
Cite This Article
APA
Najjar A, Dhaouadi A, Ezzar S, Benaoun B, Khaldi S.
(2025).
Sexual arousal intensity modulates copulatory behavior and semen quality in Arabian stallions: Effects of age, origin, and collection method.
Vet World, 18(9), 2615-2625.
https://doi.org/10.14202/vetworld.2025.2615-2625 Publication
Researcher Affiliations
- Laboratory of Animal Genetic and Feed Resources LR15AGR01, National Agronomic Institute of Tunisia, University of Carthage, 1082 Tunis, Tunisia.
- Laboratory of Animal Genetic and Feed Resources LR15AGR01, National Agronomic Institute of Tunisia, University of Carthage, 1082 Tunis, Tunisia.
- National Foundation for the Improvement of the Horse Breed, Ministry of Agriculture, Water Resources and Fishes, 2020 Sidi Thabet, Ariana, Tunisia.
- National Foundation for the Improvement of the Horse Breed, Ministry of Agriculture, Water Resources and Fishes, 2020 Sidi Thabet, Ariana, Tunisia.
- Laboratory of Epidemiology of Enzootic infections in Domestic Herbivores LR16AGR01, National School of Veterinary Medicine of Sidi Thabet, University of La Manouba, 2020 Sidi Thabet, Ariana, Tunisia.
Conflict of Interest Statement
The authors declare that they have no competing interests.
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