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Addressing Combative Behaviour in Spanish Bulls by Measuring Hormonal Indicators
Juan Carlos Illera1, Francisco Jimenez-Blanco1, Luis Centenera1
1Department Animal Physiology, Veterinary Medicine School, Complutense University of Madrid (UCM), 28040 Madrid, Spain.
Veterinary Sciences
|April 26, 2024
Summary
Hormone levels in young bulls can predict adult aggressiveness. Serotonin and dopamine levels in calves correlate with fighting bull combativeness, enabling reliable selection for breeding.
Area of Science:
- Animal behavior science
- Endocrinology
- Veterinary science
Background:
- Aggressiveness in fighting bulls is a key trait, but its physiological underpinnings are not well understood.
- Hormonal influences on aggressive behavior in these animals require further investigation.
Purpose of the Study:
- To investigate the hormonal basis of aggressiveness in fighting bulls.
- To correlate behavior during fights with serotonin, dopamine, and testosterone levels.
- To assess if aggressive behavior can be predicted in calves.
Main Methods:
- Behavioral analysis of 195 fighting bulls during fights.
- Hormone level determination (serotonin, dopamine, testosterone) in calves and at 5 years old using enzyme immunoassay.
- Correlation analysis between hormone levels and aggressiveness scores.
Main Results:
- Significant correlations were found between serotonin and dopamine levels and aggressiveness scores in adult bulls.
- Testosterone levels did not correlate with aggressiveness.
- Established cut-off points and regression curves allowed accurate prediction of aggressiveness in calves.
Conclusions:
- Serotonin and dopamine levels in calves are strong indicators of future combativeness in fighting bulls.
- Hormone determination in young animals can reliably aid in the selection of fighting bulls.
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