Falk M, Münger A, Dohme-Meier F
Agroscope, Institute for Livestock Sciences ILS, 1725 Posieux, Switzerland; Veterinary Physiology, Vetsuisse Faculty, University of Bern, CH-3001 Bern, Switzerland.
Agroscope, Institute for Livestock Sciences ILS, 1725 Posieux, Switzerland.
J Dairy Sci. 2016 Mar;99(3):1951-1955. doi: 10.3168/jds.2015-9725. Epub 2015 Dec 24.
Subacute ruminal acidosis is one of the most important digestive disorders in high-yielding dairy cows fed highly fermentable diets. Monitoring of forestomach pH has been suggested as a potentially valuable tool for diagnosing subacute ruminal acidosis. The objective of the present study was to compare continuously recorded measurements of an indwelling telemetric pH sensor inserted orally in the reticulum with those obtained from a measurement system placed in the ventral sac of the rumen through a cannula. The experiment was conducted with 6 ruminally cannulated Holstein cows kept in a freestall barn. Equal numbers of cows were assigned to 2 treatment groups based on their previous lactation milk yield. Cows in treatment CON- were offered a diet consisting of only fresh herbage cut once daily, and cows in treatment CON+ got fresh herbage plus a concentrate supplement according to the individual milk yield of each cow to meet their predicted nutrient requirements. The experiment lasted from 2 wk before the predicted calving date until wk 8 of lactation. During the whole experiment, a pH value was recorded every 10 min in the reticulum using a wireless telemetry bolus including a pH sensor (eBolus, eCow Ltd., Exeter, Devon, UK), which had been applied orally using a balling gun. Simultaneously, in wk 2, before the estimated calving date and in wk 2, 4, 6, and 8 of lactation, the ruminal pH was measured every 30 s for 48 h with the LRCpH measurement system (Dascor Inc., Escondido, CA) placed in the ventral sac of the rumen through the cannula. The readings of the LRCpH measurement system were summarized as an average over 10 min for statistical analysis. The recorded pH values were on average 0.24 pH units higher in the reticulum than in the rumen. The reticular pH also showed less fluctuation (overall SD 0.19 pH units) than pH profiles recorded in the rumen (overall SD 0.51 pH units). Regardless of measurement system, pH was not influenced by treatment, but varied across week of lactation and decreased with advancing lactation. The difference between ruminal and reticular pH varied across week of lactation. Due to this variation, no fixed conversion factor can be provided to make pH measurements in the reticulum comparable with those in the rumen.
亚急性瘤胃酸中毒是饲喂高发酵性日粮的高产奶牛最重要的消化紊乱疾病之一。监测前胃pH值被认为是诊断亚急性瘤胃酸中毒的一种潜在有价值的工具。本研究的目的是比较经口插入网胃的植入式遥测pH传感器连续记录的测量值与通过瘤胃瘘管放置在瘤胃腹囊中的测量系统获得的测量值。实验在6头安装了瘤胃瘘管的荷斯坦奶牛身上进行，这些奶牛饲养在自由牛舍中。根据它们之前的泌乳量，将数量相等的奶牛分配到2个处理组。CON-组的奶牛仅饲喂每天切割一次的新鲜牧草，CON+组的奶牛除新鲜牧草外，还根据每头奶牛的个体产奶量添加精料补充料，以满足其预测的营养需求。实验从预计产犊日期前2周持续到泌乳第8周。在整个实验期间，使用包括pH传感器的无线遥测丸剂（eBolus，eCow Ltd.，埃克塞特，德文郡，英国）经口投服，每10分钟记录一次网胃中的pH值。同时，在预计产犊日期前的第2周以及泌乳的第2、4、6和8周，通过瘤胃瘘管将LRCpH测量系统（Dascor Inc.，埃斯孔迪多，加利福尼亚州）放置在瘤胃腹囊中，每30秒测量瘤胃pH值48小时。LRCpH测量系统的读数汇总为10分钟的平均值用于统计分析。记录的pH值在网胃中的平均比瘤胃中的高0.24个pH单位。网胃pH值的波动也比瘤胃中记录的pH曲线小（总体标准差为0.19个pH单位，瘤胃中为0.51个pH单位）。无论测量系统如何，pH值不受处理的影响，但随泌乳周数变化，且随着泌乳进展而降低。瘤胃和网胃pH值的差异随泌乳周数而变化。由于这种变化，无法提供固定的转换因子以使网胃中的pH测量值与瘤胃中的测量值具有可比性。
