Technical note: Evaluation of the ororuminal FLORA sampling device for rumen fluid sampling in intact cattle

The objectives of this study were to evaluate the actual intraruminal sampling site of the ororuminal FLORA sampling device (Profs Products, Wittibreut, Germany), and to compare pH and volatile fatty acid (VFA) data obtained using FLORA and those obtained using a suction strainer introduced to the ventral ruminal sac via a rumen cannula. Five lactating multiparous Danish Holstein cows fitted with ruminal cannulas were used. All cows were fed the same diet once daily, and the diet was allowed ad libitum. Samples of rumen fluid and recordings were obtained 6 h after feeding at 3 occasions. Rumen fluid samples were taken using 2 devices: (1) the ororuminal FLORA sampling device and (2) a suction strainer inserted through the rumen cannula to the ventral ruminal sac and a 60-mL syringe for suction. Both sampling devices were inserted concomitantly, and samples of rumen fluid were obtained simultaneously with both devices. After sampling rumen fluid, the actual intraruminal placement of the FLORA sampling cup was manually assessed as being in either the cranial sac, the dorsal sac, the medial layer, or the ventral sac. Only VFA proportions, and not pH and VFA concentrations, were similar between rumen fluid samples obtained using FLORA and those obtained directly through the rumen cannula. The observed intraruminal sampling site of the FLORA sampling cup indicates that firm rumen digesta hampers the ability of the FLORA device to reach the ventral sac and impedes filling of the sampling cup and, consequently, increases the risk of saliva contamination of samples.