Impact of Oral Phytozen EQ Supplementation on Plasma Cortisol and Behavior Responses of Young Horses Exposed to Stressful Stimuli.
Authors: Thomson-Parker Timber L, Fikes Kalley K, Anderson Mark J, Wagner Ashley L, Girard Ivan D, Suagee-Bedore Jessica K
Journal: Journal of equine veterinary science
Summary
Phytozen EQ, a supplement combining citrus botanical oils, magnesium, and yeast, was evaluated in a 59-day trial involving 14 young horses (aged 1.5–6 years) to determine whether it could mitigate physiological and behavioural stress responses during challenging situations. Horses received either 56 g daily of the active supplement (n = 7) or placebo (n = 7), then underwent isolation tests, individual trailering trials with plasma cortisol sampling at three timepoints, and a startle response assessment measuring speed and distance travelled. Supplemented horses demonstrated a trend towards lower cortisol concentrations during trailering (61 ng/mL versus 81 ng/mL; P = 0.071) and took approximately five times longer to cover 3 metres during the startle test (1.35 versus 0.26 seconds; P = 0.064), though these differences did not reach statistical significance. The findings suggest potential benefits of this supplement for horses experiencing transport stress or novel environments, though larger-scale trials would be needed to establish clinical efficacy and determine which component ingredients drive any observed effect. For practitioners working with anxious young stock or those prone to trailering difficulties, these preliminary results warrant further investigation, particularly given the absence of adverse effects.
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Practical Takeaways
- •Phytozen EQ may help reduce stress responses in young horses during trailering and novel situations, though effects are modest and not yet conclusively proven
- •The supplement showed trends toward lower cortisol and reduced startle responses, making it worth considering for anxious or reactive young horses, particularly those being transported
- •Current evidence is preliminary; more research with larger sample sizes is needed before recommending this as a primary stress management tool in practice
Key Findings
- •Phytozen EQ-supplemented horses showed a trend toward lower plasma cortisol during trailering (61 vs 81 ng/mL; P=0.071)
- •Phytozen EQ-supplemented horses tended to have longer times to travel 3m in startle tests, suggesting reduced reactivity (1.35 vs 0.26 seconds; P=0.064)
- •No significant differences between treatment and control groups during isolation stress testing (P>0.1)
- •Daily supplementation of 56g Phytozen EQ for 59 days showed potential but not statistically significant calming effects