Abstract：
Cattle lameness remains a significant concern, causing economic losses and compromising animal welfare. Claw horn lesions have been identified as a major cause of lameness in dairy cows, but their correlation with high-energy diets and ruminal acidosis remains unclear. Hence, the primary objective of this study was to assess the effects of a high-starch diet and a conventional diet on the rumen environment, acute-phase proteins, and metabolic alterations, with a particular focus on insulin resistance and the consequent implications for the histology of the hooves in Holstein steers. A total of 16 animals were divided into the high-starch (HS; 37% starch) and conventional (CON; 16.8% starch) groups. Glucose tolerance tests (GTT), blood analyses, rumen fluid analyses, and histological evaluations of the hoof tissue were conducted over a 102-d experimental period. The HS group showed a lower ruminal pH than the CON group, and with values indicating SARA. The plasma glucose and IGF-1 concentrations were higher in the HS group, suggesting an anabolic state. Both groups exhibited an increase in the insulin area under the curve (AUC) after the GTT on d 102. Histological analysis of the hooves showed a reduction in the length and width of the epidermal lamella in both groups. We found a significant negative correlation between the insulin AUC and the length and width of the epidermal lamella. Because both groups were similarly affected, the hypothesis that histological alterations were caused by the experimental diets still needs confirmation. Additionally, the development of SARA was not essential for the observed histological changes in the hoof. Further studies are warranted to thoroughly investigate the role of insulin and IGF-1 imbalances in claw health.
摘要：
牛跛行仍然是一个重要的问题，造成经济损失，损害动物福利。羊角病变已被确定为奶牛跛行的主要原因，但其与高能量饮食和瘤胃酸中毒的相关性仍不清楚。因此，这项研究的主要目的是评估高淀粉和常规饮食对瘤胃环境的影响，急性期蛋白，和代谢改变，特别关注胰岛素抵抗及其对荷斯坦牛蹄组织学的影响。将16只动物分为高淀粉组(HS;37%淀粉)和常规组(CON;16.8%淀粉)。葡萄糖耐量试验（GTT），血,瘤胃液分析,在102天的实验期内对蹄组织进行了组织学评估。HS组瘤胃pH值低于CON组,值表明亚急性瘤胃酸中毒（SARA）。HS组血浆葡萄糖和IGF-1浓度较高,表明存在合成代谢状态。在第102天进行GTT后，两组的曲线下胰岛素面积（AUC）均增加。蹄的组织学分析表明，两组表皮薄片的长度和宽度均减少。胰岛素AUC与表皮薄片的长度和宽度之间存在显着负相关。由于两组都受到类似的影响，组织学改变是由实验饮食引起的假设仍需要证实。此外,SARA的发展对于观察到的蹄组织学变化不是必需的。需要进一步的研究来彻底研究胰岛素和IGF-1失衡在爪健康中的作用。
