Exploring the impact of high-energy diets on cattle: Insights into subacute rumen acidosis, insulin resistance, and hoof health.

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.

Correlation between ruminal pH and body condition score in cows with subacute ruminal acidosis / Correlación entre el pH ruminal y el índice de condición corporal en vacas con acidosis ruminal subaguda

ABSTRACT Objective. The purposes of this field study were to a) confirm the presence of subacute ruminal acidosis (SARA) in Turkish dairy herds in Aydin region, b) record its regional distribution and c) to determine whether there is a relationship between body condition scoring, ruminal contractions and ruminal pH. Materials and methods. Ruminal fluid samples, via rumenocentesis, were withdrawn from a total of 120 Holstein dairy cows, from 5 herds (n=24 cows per herd). Rumen pH was analyzed on-site with a portable pH-meter for a precise SARA diagnosis. Classical body condition scoring systems (USBCS method) were utilized within 1-5 scale with 0.25 intervals. Results. Out of 120 cows enrolled 13 were (10.83%) classified as affected with SARA (pH<or=5.5), 6.6% were marginal (pH 5.6-5.8) and 82.5% were normal (pH>5.8). There was a significant difference (p<0.01) among farm V and other farms regarding mean ruminal pH. The overall means of BCS were found as 3.45±0.037, 3.43±0.122 and 4.30±0.075 in healthy animals, SARA suspected cows and cows with SARA, respectively with increased BCS in cows with SARA (p<0.01). Inter group comparison of ruminal contractions showed statistical significance (p<0.01). There were correlations among ruminal pH and ruminal contraction (r=0.622, p<0.01), ruminal pH and health status (r=-0.770, p<0.01), rumen contraction and health status (r=0.546, p<0.01). Conclusions. In the present study BCS and ruminal contractions data were used as indicators, in which correlations were found among ruminal pH and ruminal contraction and ruminal pH and BCS, favoring the usage or those parameters as probable biomarkers in cows with SARA.

RESUMEN Objetivo. Los objetivos de este estudio de campo fueron a) confirmar la presencia de acidosis ruminal subaguda (SARA) en los rebaños de vacas lecheras turcas en la región de Aydin, b) registrar su distribución regional y c) determinar si existe una relación entre las puntuaciones del estado corporal, ruminal Contracciones y pH ruminal. Materiales y métodos. Se extrajeron muestras de líquido ruminal, a través de rumenocentesis, de un total de 120 vacas lecheras Holstein, de 5 hatos (n = 24 vacas por rebaño). El pH del rumen se analizó en el sitio con un pH-metro portátil para un diagnóstico preciso de SARA. Los sistemas clásicos de clasificación de estado corporal (método USBCS) se utilizaron en escala 1-5 con intervalos de 0,25. Resultados. De las 120 vacas inscritas, 13 fueron (10.83%) clasificadas como SARA (pH =5.5), 6.6% marginales (pH 5.6-5.8) y 82,5% normales (pH>5.8). Hubo una diferencia significativa (p<0.01) entre la finca V y otras fincas con respecto al pH ruminal medio. El promedio global de BCS fue de 3.45±0.037, 3.43±0.122 y 4.30±0.075 en animales sanos, SARA sospechosos de vacas y vacas con SARA, respectivamente con aumento de BCS en vacas con SARA (p<0.01). La comparación intergrupal de contracciones ruminales mostró significación estadística (p<0.01). Hubo correlaciones entre el pH ruminal y la contracción ruminal (r=0.622, p<0.01), pH ruminal y estado de salud (r =-0.770, p<0.01), contracción ruminal y estado de salud (r=0.546, p<0.01). Conclusiones. En el presente estudio se utilizaron indicadores BCS y contracciones ruminal como indicadores, en los que se encontraron correlaciones entre pH ruminal y contracción ruminal y pH ruminal y BCS, favoreciendo el uso o esos parámetros como biomarcadores probables en vacas con SARA.