108 M. H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, KY.
Equine studies Group, Waltham Petcare Science Institute, Freeby Lane, Waltham-on-the-Wold, Leics. LE14 4RT, Leics, United Kingdom.
J Equine Vet Sci. 2022 Jun;113:103945. doi: 10.1016/j.jevs.2022.103945. Epub 2022 Apr 8.
Seasonal effects on the oral sugar test (OST), used to monitor insulin dysregulation (ID) status to help reduce laminitis risk, are poorly understood in the ID horse. Resting, (basal) insulin (T0) and 60-minute (T60) OST (0.15 mL/Kg BW Karo Light Corn Syrup) insulin responses were evaluated, once per each season over 2 years, in ID (n = 11 14.9 ± 4.3 years; mean ± SD) and non-insulin dysregulated (NID: n = 11 16.4 ± 5.3 years; mean ± SD) horses housed on the same farm. Seasonal morphometric measurements were collected: bodyweight (BW), body-condition scores (BCS), and cresty neck scores (CNS). Seasonal forage from paddocks and hay were collected and analyzed. Insulin was measured by RIA. Data were analyzed via Minitab Software 20.2 (mixed effects model). Season had no effect on BW (P = .99); however, BCS and CNS were higher in ID versus NID in the spring, summer and fall (P < .02). Paddock (P < .05) but not hay (P > .2) analytes varied across season. ID horses consistently had higher T0, T60 insulin concentrations versus NID (P < .02). Season had no effect on NID T0 insulins (P = .31), but T60 values were higher in the spring versus summer (P = .01). ID horses' T0 & T60 insulins were higher in spring than fall and summer (P < .01 & P < .05) and winter T60 was higher than fall (P = .04). ID horses changed their ID categorization across season, with T0 confirming ID status only 56% of the time whilst T60 confirmed 94% of the time. Therefore, regardless of seasonal changes, if the OST was used, ID diagnosis would be more consistent.
季节变化对口服糖耐量试验（OST）有影响，OST 用于监测胰岛素失调（ID）状态，以帮助降低蹄叶炎风险，但在 ID 马中，这种影响的了解还很有限。在 2 年内，每个季节评估一次 ID（n=11，年龄 14.9±4.3 岁；平均值±标准差）和非胰岛素失调（NID：n=11，年龄 16.4±5.3 岁；平均值±标准差）马的静息（基础）胰岛素（T0）和 60 分钟（T60）OST（0.15mL/Kg BW Karo 淡玉米糖浆）胰岛素反应。ID 马和 NID 马饲养在同一农场，采集了季节性形态学测量值：体重（BW）、体况评分（BCS）和高颈评分（CNS）。采集并分析了来自围场和干草的季节性饲料。胰岛素采用 RIA 法测定。数据通过 Minitab 软件 20.2（混合效应模型）进行分析。季节对 BW 无影响（P=0.99）；然而，ID 马的 BCS 和 CNS 在春季、夏季和秋季高于 NID（P<0.02）。围场（P<0.05）而不是干草（P>0.2）分析物随季节而变化。ID 马的 T0 和 T60 胰岛素浓度始终高于 NID（P<0.02）。季节对 NID 的 T0 胰岛素无影响（P=0.31），但 T60 值在春季高于夏季（P=0.01）。ID 马的 T0 和 T60 胰岛素在春季高于秋季和夏季（P<0.01 和 P<0.05），冬季 T60 高于秋季（P=0.04）。ID 马在季节之间改变了 ID 分类，T0 仅在 56%的时间内确认 ID 状态，而 T60 则在 94%的时间内确认 ID 状态。因此，无论季节如何变化，如果使用 OST，ID 诊断将更加一致。
