Long-Term Recording of Reticulo-Rumen Myoelectrical Activity in Sheep by a Telemetry Method

Abstract

The reticulum and rumen are considered a single functional unit (the reticulo-rumen) with regards to myoelectrical and contractile activities. The specialized contractions of the reticulo-rumen provide constant mixing of partially digested material (cycle A), its flow into the omasum during eructation (cycle B), and regurgitation-rumination (cycle C). This study aimed to investigate the feasibility of electromyography (EMG) registered by a long-term telemetry method for assessment of the basic reticulo-rumen myoelectrical activity in sheep, to develop the effective recognition of the reticulo-rumen cycles at rest with no food stimulation, and to investigate the relationship between cycles A, B, and C in such basic conditions. The experiment was carried out on nine ewes. Myoelectric activity of the rumen, reticulum, and abomasum was recorded by the combination of three silver bipolar electrodes and a 3-channel transmitter implant. The myoelectrical activity registered successfully in the reticulum and rumen was determined as three characteristic patterns of cycles A, B, and C. The percentage of each type of cycle changed at different intervals from equally cycles A (43–50%) and B (50–56%), occurring when cycle C was not observed to the domination of cycle C (57–73%) with a decrease of cycles A (6–14%) and B (20–28%). The long-term EMG telemetry registration is feasible in the assessment of the reticulo-rumen myoelectrical activity in sheep.

Induction of hypocalcaemia and evaluation of reticuloruminal motility using a three-axis accelerometer

“…Second, the bolus-type sensor with 3XA located in the reticulum detects and records reticuloruminal motility indirectly according to the movement of reticular walls or the flow of its contents. Recently, electrodes were surgically attached to sheep to assess the EMG activity of reticuloruminal smooth muscle directly, and the transmitted data could be recorded wirelessly for ~2 months (Wierzbicka et al 2021). So as to prevent a productivity decrease in cattle caused by forestomach problems, further studies to develop a non-invasive and accurate method based on these studies are necessary.…”

“…Biosensors have been applied to measure vital signs and physical activities such as body temperature, respiratory rate, lameness and exercise, and to evaluate productivity indicators such as ovarian cycles and delivery time. Among them, the implanted electrodes recorded the contraction patterns of the smooth muscle to analyse the myoelectrical activities of the reticulo-rumen in sheep, and they enabled wireless electromyography (EMG) telemetry registration (Wierzbicka et al 2021). In contrast, a bolustype accelerometer in the reticulum and a force transducer on the ruminal sac could detect both the frequency and amplitude of rumen motility accurately and effectively (Arai et al 2019;Hamilton et al 2019;Choi et al 2020).…”

Providing baseline data for conservation–Heart rate monitoring in captive scimitar-horned oryx

“…Data from two animals had to be excluded from the analysis because of a higher rate of erroneous detection of T-waves and electric noise as heartbeats (Figure 2B). Due to a reduced number of individuals tested for right side placement, we cannot properly assess the source of the electrical noise, but the biologger could potentially be detecting electrical signals originating from the different compartments of the stomach (Wierzbicka et al, 2021). Erroneous automated detection of ventricular depolarization (QRS) may limit long-term monitoring of heart rate in other ungulate and cetacean species, which share similar anatomical and electrophysiological characteristics of the heart (Ono et al, 2009;De Almeida et al, 2015).…”

Evaluation of an indwelling bolus equipped with a triaxial accelerometer for the characterisation of the diurnal pattern of bovine reticuloruminal contractions

“…Methods for measuring the RRCR are classified as either invasive or non-invasive, depending on whether surgery is required to apply the measuring device (Braun and Rauch, 2008; Han et al ., 2022). Invasive methods include electrodes applied in the forestomach to measure electrical activity (Plaza et al ., 1996; Wierzbicka et al ., 2021) and placement within the reticulum of air- or water-filled pressure devices (Holtenius et al ., 1971; Egert-McLean et al ., 2019; Scheurwater et al ., 2021). Non-invasive methods include ultrasonography and indwelling reticuloruminal boluses, which directly measure reticular movement; less direct non-invasive methods include clinical examination, auscultation and palpation of the paralumbar fossae; however, they cannot differentiate between primary and secondary cycles (Grünberg and Constable, 2009).…”