It is unknown whether short-term transportation affects endocrine responses similarly in horses with and without insulin dysregulation (ID). This longitudinal cohort study aimed to characterize the effect of short-term transportation on stress parameters and insulin responses to an oral sugar test (OST) in horses with and without ID.
Study Population and Methodology
Fourteen adult, nonpregnant, non-PPID mares of mixed light breeds were categorized as either ID (n = 7) or non-ID (n = 7) based on endocrine testing. Over two weeks, horses were transported once in groups of three to four in a horse trailer on a round-trip journey of approximately 1.5 hours. Researchers collected blood and saliva 24 hours and 1 hour pre-transportation, directly after unloading, and 15 minutes, 1 hour, 3 hours, and 24 hours post-transportation. They performed OST 24 hours pre-transportation and 3 hours post-transportation with a pre- (T0) and post-OST sample collected 60 minutes later (T60). Heart rates and rectal temperatures were also collected throughout the study. Serum insulin, serum cortisol, and plasma glucose were measured using validated assays. Repeated measures ANOVA were used to determine differences after transportation and between ID and non-ID horses.
Study Results
Mean insulin was higher in ID horses versus non-ID horses (mean = 109.9 μU/mL vs. 30.2 μU/mL, p < 0.001; 95% CI for mean difference = [55.6–107.7 μU/mL]). Mean serum insulin increased following OST at T60 in ID horses pre- (154.6 μU/mL, p = 0.04; 95% CI = [86.3–223.0 μU/mL]) and post-transportation (284.6 μU/mL, p = 0.03; 95% CI = [114.3–454.8 μU/mL]). Non-ID horses had a mean OST T60 insulin post-transportation of 56.6 μU/mL (95% CI = [29.1–84.1 μU/mL]), which is above the recognized threshold [45 μU/mL] for ID diagnosis.
Bottom Line
Performing an OST three hours after short-term transportation might result in inaccurate ID status.
https://beva.onlinelibrary.wiley.com/doi/10.1111/evj.14403
Related Reading
- Diagnosing and Managing Hyperinsulinemia in Horses
- Factors Associated with Insulin Responses to Oral Sugars in a Mixed-Breed Cohort of Ponies
- Management of Hyperinsulinemia and Laminitis With Ertugliflozin
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