Technical note--a comparison of methods used to measure eating and ruminating activity in confined dairy cattle.

Detailed knowledge of chewing and rumination activities is critical to fully understand the dietary factors affecting normal rumen function. An automatic system for the digital recording of the jaw movements in free-ranging grazing cattle has been described, but its ability to measure chewing activity of cattle housed in confinement and fed total mixed rations has not yet been evaluated. The eating and ruminating behaviors of eight lactating dairy cows were recorded simultaneously by a wireless automatic system and by 5-min interval observation over 24-h periods. Results indicated that both methods agreed on identification of eating and ruminating bouts. Mean differences between methods for total time eating (8.7 min +/- 12.8) and ruminating (42.9 min +/- 12.0) were significantly different. The time recorded by observation in both eating and rumination was 3.6 and 10.3% higher compared with the automatic system. Differences indicate inaccuracies in the observational method itself. The automatic system may prove useful in further studies examining eating and rumination activities in cattle.