Quantitative analysis of nycterohemeral eating and ruminating patterns in beef cattle fed pelleted concentrates with or without supplemental roughage

The effects of five diets on nycterohemeral pattern of chewing behaviour were evaluated in 10 Hereford steers according to a replicated 5 × 5 Latin square design. Steers had ad libitum access to diets, fed once daily at 09:00 h and chewing behaviour was continuously measured for 4 d. Dietary treatments were: 1) traditional diet — 80% pelleted concentrate (control) and 20% long timothy hay; 2) 80% control concentrate and 20% alfalfa cubes; 3) 90% control concentrate and 10% alfalfa cubes; 4) a completely pelleted diet with corn cobs; 5) 80% textured concentrate and 20% long timothy hay. Spectral analysis of hourly time spent either eating or ruminating was performed using the finite Fourier transform to decompose the 24-h total dispersion of chewing into 12 RC. Nycterohemeral patterns of time spent eating and ruminating different diets were mainly explained by RC 1, 2 and 3. RC 1 was relatively more important than the others in explaining total daily dispersion of time spent eating traditional completely p...