More research on geldings dropping
First, behavior should not be reduced to a single function, context, horse, observation, biochemical response, or research study. It is critically important to consider all observable behaviors, context clues, and situational factors when attempting to interpret behavior. Behavior is the study of one, and most—if not all—behavior should be evaluated on an individual and situational basis, and CAN have multiple functions and motivations.
Once again, I am presenting this data solely because it is rarely seen circulating or discussed in the broader debate on dropping. There certainly needs to be more research conducted on this topic. However, when we examine the current research available, it does seem to suggest that dropping is NOT USUALLY a sign of stress.
I am not arguing that dropping can never be a sign of stress or pain. I am simply presenting the current research we have and asking you to keep an open mind, READ the studies, seek out additional research on your own, and observe your horses' behavior with a neutral perspective. Horse owners are not always the most reliable at interpreting their horses' behavior and emotional states. And yes, there is even a study on that. Do we have some bias, preconceived notions, and superstitious behaviors ourselves?
One of the best studies was behind a pay wall. So, I bought the article, and have attached it as a Google Drive link, because I think this research should be available to the public. If you want the PDF version, I am happy to email it to you!
Key Findings from the Research:
1. Dropping in Male Horses During Training (Merkies et al., 2023)
Observation Study: Video analysis of 24 horses during training sessions.
Key Result: Dropping occurred in 69% of the sessions, with no correlation to stress behaviors such as head tossing, tail swishing, or lip licking.
Main Drivers:
Increased food rewards were linked to higher instances of dropping.
Dropping was more frequent in prime-aged horses (11-15 years).
No significant correlation with clicker use or physical touch.
Conclusion: Dropping appears related to affective states and food anticipation rather than stress responses. No evidence linked dropping to discomfort or emotional stress.
2. Spontaneous Erection and Masturbation in Equids (McDonnell et al., 1991)
Study Focus: Natural occurrences of SEAM in horses without human interaction.
Key Result: SEAM was observed frequently in relaxed, non-stressful environments such as turnout and resting periods.
Conclusion: SEAM is a normal, spontaneous behavior unrelated to stress or anxiety. It appears to be a standard physiological response in stallions and geldings under calm conditions.
3. Behavioral Indicators of Stress in Horses (Hall et al., 2013)
Study Focus: Identification of reliable stress indicators in horses.
Key Stress Indicators Identified:
Elevated head carriage.
Tail swishing.
Lip licking (when paired with other stress behaviors).
Conclusion: None of these stress behaviors were associated with dropping during training sessions in other studies, suggesting dropping is not a stress indicator.
4. The Role of Dopamine and Positive Reinforcement
Physiological Link: Dropping has been associated with the dopamine system, a neurotransmitter linked to reward and motivation rather than stress (Giuliano & Allard, 2001)
Food Rewards: Positive reinforcement training with food often triggers dopamine release, which can result in dropping without any link to stress.
5. Age and Time of Day Factors
Age: Horses between 11-15 years showed higher rates of dropping, possibly linked to peak physiological maturity rather than emotional states.
Time of Day: Dropping was less common during afternoon training sessions, aligning with circadian hormonal fluctuations (Kirkpatrick et al., 1976).
Conclusions Across Studies:
No Evidence of Stress Correlation: Dropping and SEAM were not linked with stress behaviors in any of the reviewed studies.
Physiological Basis: The behavior appears primarily linked to dopamine activity and food rewards, consistent with relaxed states.
Natural Occurrence: SEAM and dropping are common, spontaneous behaviors observed in both training and natural contexts without stress triggers.
This evidence reinforces the importance of understanding equine body language within the broader context of behavior science rather than assuming stress-based interpretations for natural physiological responses.
https://www.sciencedirect.com/.../abs/pii/S0168159123000473
Google Drive Link: https://drive.google.com/.../11_4UCD4fjUkaeY5Xs1.../view...
https://www.sciencedirect.com/.../abs/pii/S0378432005001855
https://www.mdpi.com/2076-2615/12/4/421#B23-animals-12-00421
https://www.sciencedirect.com/.../pii/S0737080606812426
https://www.sciencedirect.com/.../pii/S0749073917304662
https://www.sciencedirect.com/.../abs/pii/0014299986902773
https://academic.oup.com/.../article.../64/1/27/2653453
