Graduate Research Assistant University of Kentucky Lexington, KY, United States
Abstract: Background- Unknown how short distance transportation stress impacts horses with PPID.Hypothesis/Objectives- To determine if transportation alters diagnostic results for PPID.Animals- 12 non-insulin dysregulated horses of mixed light breed were age-matched and categorized by thyrotropin stimulating hormone (TRH) stimulation test and hypertrichosis score (HS) as PPID (n=6, T10 TRH >200pg/mL, HS≥1) and non-PPID (n=6, TRH T10< 200pg/mL, HS< 1). A further 3 PPID horses (TRH >1200pg/mL, HS≥1) were evaluated in a second study (PPID:A).Methods- Horses were transported once by road (1.5 hour round trip: 3-4 horses/trip). Blood (for ACTH, insulin, and cortisol) and saliva (cortisol) were collected on the day of transportation: 1 hour before loading, directly after unloading plus 15 minutes, 30 minutes, 1 hour, 2 hour and 24 hours post transportation. Results- At unloading and 15 minutes post-transportation serum cortisol was significantly increased in PPID and non-PPID horses (P< 0.01), while salivary cortisol was increased in non-PPID horses (P< 0.05). Plasma ACTH was 2-4x higher in PPID horses vs non-PPID horses at unloading (P=0.02) and 15 minutes post-transportation (P=0.02). 2 non-PPID horses had unloading post-transportation ACTH concentrations above the basal ACTH diagnostic cut off for PPID ( >40pg/mL). There were no differences in serum insulin in response to transportation or PPID status. PPID:A horses had increased ACTH concentrations at 15 minutes post-transportation (P< 0.05); serum cortisol was 3x lower than PPID/non-PPID horses.Conclusions and clinical importance- Caution should be taken when performing diagnostic testing for PPID shortly after short distance transportation due to possible increased ACTH.
