Insulin dysregulation in the non-obese stock-type horse

This is interesting information but I am not sure what to do with it. Nearly 5% of 63 non-obese horses had insulin dysregulation as measured by the oral sugar test. What should be done is to follow these horses to see if they become obese or perhaps they are predisposed to founder. Also consideration of the significance of the OST findings should be investigated.
DrO

Prevalence of insulin dysregulation in the non-obese stock-type horse and relationship with morphometric neck measurements

J Equine Vet Sci. 2024 Jul 26:105151. doi: 10.1016/j.jevs.2024.105151. Online ahead of print.
Authors
C P Heaton 1 , C A Cavinder 2 , E N McClure 2 , T Smith 2 , W B Smith 3 , N Liburt 4 , A Krotky 4 , P Harris 4
Affiliations

1 Department of Animal and Dairy Sciences, Mississippi State University, Mississippi State, Mississippi, 39762. Electronic address: cph0032@auburn.edu.
2 Department of Animal and Dairy Sciences, Mississippi State University, Mississippi State, Mississippi, 39762.
3 Department of Animal Sciences, Auburn University, Auburn, Alabama, 36849.
4 Mars Horsecare U.S., Inc., Dalton, Ohio, 44618, Waltham Petcare Science Institute, Melton Mowbray, LE14 4RT, United Kingdom.

PMID: 39069238
DOI: 10.1016/j.jevs.2024.105151

Abstract

Insulin dysregulation (ID), core to equine metabolic syndrome, may present without obesity. Testing for ID risk is commonly based on breed and obese phenotype but might be valuable for non-obese stock-type horses. This study aimed to determine the prevalence of ID in non-obese stock-type horses and evaluate if morphometric neck measurements (MNM) correlate with ID. Sixty-two, non-obese (BCS 5, range 2.5-6/9) stock-type horses were assessed for MNM: neck circumference at 25%, 50% (NC50), and 75% (NC75) length, and crest height. An oral sugar test (OST; 0.15 mL/kg BW corn syrup) was performed with blood taken pre- and 60 min post-OST for insulin (PREI, POSTI) and glucose (PREG, POSTG). Insulin dysregulation was defined as insulin concentration > 45 µIU/mL POSTI. Three of 62 horses were ID (4.8%, 95% CI 1.0%-13.5%). Horses with ID had greater PREG (121.0 ± 7.56 vs. 105.3 ± 1.72 mg/dL; LS means ± SEM; P = 0.04) and PREI (15.7 ± 2.63 vs. 10.5 ± 0.59 µIU/mL; P = 0.05) than normal responders. Mares had greater PREI than geldings (11.7 ± 0.76 vs. 9.4 ± 0.89 µIU/mL; P = 0.04). Stepwise regression indicated a weak relationship with crest height and POSTG (y = 51.27 + (0.88 x NC50); R2 = 0.09; P = 0.02). Post-glucose correlated with NC50 (r = 0.30; P = 0.04) and NC75 (r = 0.29; P = 0.03). This study showed 4.8% of non-obese horses had ID, warranting testing irrespective of phenotype, but only a weak association between MNM and POSTG was found.

Keywords: insulin dysregulation; morphometric neck measurement; obesity; oral sugar test; stock-type.

Copyright © 2024. Published by Elsevier Inc.