The ingestive behavior patterns were evaluated in nine sheep 1/2 Texel + 1/2 Ile-de-France over a six month period. Sheep were fed the diet at 9 a.m. and 4 p.m., which was composed by 250 g of concentrate (15.45% CP, 36.54% NDF) and ad libitum grass hay (6.69% CP, 69.10% NDF). Ingestive behavior was continuously measured for five days per period, and its activities or states were classified as eating, ruminating or idling, and sequentially registered. The probability estimates incorporated three types: The probabilities of being in a given state, of staying in a given state and of changing from a state to another one. Finite Fourier transformation was applied to the series of probabilities estimated at each five minutes, during 22 hours per day. In the nycterohemeral probabilities distribution study, it was used the analysis of periodgrams, phase diagrams and analysis of variance upon the transformed values of the probabilities series. The analysis of variance showed that all probability types followed a nycterohemeral distribution, and it was significantly affected by experimental period and animals at several frequencies. Analysis of periodgrams and phase diagrams showed that differences between the experimental periods and animals was mainly due to differences in the amplitude of trigonometric functions that described the nycterohemeral distribution of probabilities of being or staying in a given state. The day moment, the experimental period and individuals affected the nycterohemeral distribution of the transition state probabilities.
finite Fourier transform; periodograms; phase diagrams
