Effects of rumen cannulation surgery on physiological parameters and rumen fluid pH in Korean native Hanwoo cattle

Rumen cannulation is used for nutritional and microbiological research, clinical diagnosis, and rumen component transfaunation. However, the cannulation procedure can affect parameters such as complete blood count findings, serum chemistry, and rumen fluid pH. The objective of this study was to evaluate the health risks related to the rumen cannulation procedure over a 1-month period. We did not identify significant differences in red blood cell numbers or morphologies between pre- and postoperative timepoints. Moreover, no inflammation or infection was detected. Despite the absence of apparent clinical signs after surgery, serum chemistry results revealed changes in blood urea nitrogen levels and the activities of liver enzymes, including aspartate transaminase, lactate dehydrogenase, and creatinine kinase, from postoperative days 1 to 14. Rumen fluid pH, as measured from samples collected via an orogastric tube, was slightly increased after a preoperative fasting period and on postoperative day 1 but decreased thereafter from postoperative day 4, indicating a minor influence of cannulation surgery on ruminal fluid pH. This is the first study to evaluate hematological parameters and rumen pH before and after rumen cannulation surgery in Hanwoo cattle. Further research is required to better elucidate the potential effects of rumen cannulation surgery on animal health.