Meals have long been considered relevant units of feeding behavior. Large data sets of feeding behavior of cattle, pigs, chickens, ducks, turkeys, dolphins, and rats were analyzed with the aims of 1) describing the temporal structure of feeding behavior and 2) developing appropriate methods for estimating meal criteria. Longer (between-meal) intervals were never distributed as the negative exponential assumed by traditional methods, such as log-survivorship analysis, but as a skewed Gaussian, which can be (almost) normalized by log-transformation of interval lengths. Log-transformation can also normalize frequency distributions of within-meal intervals. Meal criteria, i.e., the longest interval considered to occur within meals, can be estimated after fitting models consisting of Gaussian functions alone or of one Weibull and one or more Gaussian functions to the distribution of log-transformed interval lengths. Nonuniform data sets may require disaggregation before this can be achieved. Observations from all species were in conflict with assumptions of random behavior that underlie traditional methods for criteria estimation. Instead, the observed structure of feeding behavior is consistent with 1) a decrease in satiety associated with an increase in the probability of animals starting a meal with time since the last meal and 2) an increase in satiation associated with an increase in the probability of animals ending a meal with the amount of food already consumed. The novel methodology proposed here will avoid biased conclusions from analyses of feeding behavior associated with previous methods and, as demonstrated, can be applied across a range of species to address questions relevant to the control of food intake.

International audience1. This study is the first to quantitatively compare the structure of feeding behaviour of broilers, ducks and turkeys as recorded by electronic feeders. It tests the hypothesis that this structure is so similar that the same models would be suitable to group the feeding behaviour of these species into meals. 2. Visits to electronic feeders were recorded from 3,470 broilers, 3,314 turkeys and 480 ducks. The frequency distributions of the length of short intervals to feeders varied between species as a result of differences in the number of visits within a feeding bout, the frequency of re-visits to the same feeder and probably in the likelihood of birds drinking within meals. 3. The lengths of longer day-time intervals between visits to feeders were all log-normally distributed. Disaggregation of these intervals by feeding strategy (i.e. meal frequency) showed that the probability of birds starting to feed increased with time since feeding last in all species, which is consistent with the satiety concept. 4. Two methods, one based on fitting a truncated log-normal, the other on observed changes in the probability of birds starting to feed with time since feeding last, gave very similar meal criteria estimates. These ranged from 1050 to 1200 sec in broilers, 1650 to 1725 sec in ducks and 1250 to 1320 sec in turkeys. 5. There were large between-species differences in the average number of daily meals, intake per meal, and feeding rate. Despite this variation, the overall structure of feeding behaviour of broilers, ducks and turkeys was so similar that the same models were suitable for application in all three species. This would allow for standardised analyses of feeding behaviour of different avian species kept in different husbandry systems

Intracranial astrocytomas are rarely diagnosed in cats. Clinical and pathological aspects of these tumors are more often described in humans and dogs. The classification scheme used in human medicine is of important prognostic value. We have analyzed clinical neurological and pathological findings from 8 cats with intracranial astrocytomas. The animals were 10.1 years old in average and presented with a history of tetraparesis (n = 3), epilepsy (n = 2), loss of balance (n = 3) and dyspnoe (n = 1). The latter cat died immediately after the first presentation while the other animals were euthanized because of a progressive course of the symptoms despite therapy. Even though feline astrocytomas, that we could classify into 4 different types in this study, are clinically and pathologically well correlated with those of other species, a prognostically useful classification has never been established before.

The temporal pattern of feed intake for individual ducks kept in groups was studied using a radio frequency identification system, to enable the continuous recording of feeding characteristics for a large numbers of animals over long periods. A total of 50 male ducks were used in experiment 1 and 480 male and female ducks in experiment 2. The bird:feeder ratio was 10:1 for both experiments. The birds were fed with a commercial pelleted duck grower ad libitum. For experiment 1, the BW, the amount and duration of feed intake, the number of meals, meal size, and feeding rate were recorded for ages from 3 to 7 wk and from 4 to 6(1/2) weeks for experiment 2. On the basis of the number of meals per day, the birds were assigned to 3 meal categories: high (H), low (L), and intermediate (I). The L-type ducks showed a higher feed consumption, BW, and meal size than I- and H-type ducks. The pattern of meal type and the interrelations among meal type, BW, feed intake, and other characteristics of feed intake were consistent for both experiments, throughout the experimental period. The relative frequency of pauses between feeding was plotted against the duration of the pauses for the H- and L-type ducks. The H-type birds showed a high number of pauses of less than 30 min in duration. The frequency of short meals declined with age for both meal types, whereas the frequency of larger meals increased.

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