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

Energy requirements of animals are most readily expressed in terms of net energy (NE), while the energy yield of feed is, at least initially, expressed in terms of metabolisable energy (ME). Energy evaluation systems 'translate' NE requirements into ME requirements (ME systems) or assign NE values to feeds (NE systems). Efficiency of ME utilisation is higher for maintenance than for production and the NE yield of a feed varies, therefore, with ME intake. In addition, energetic efficiency for maintenance and production is thought to be different for lactating and non-lactating animals and to be affected by diet quality. As a result, there are currently many national energy evaluation systems that are complex, differ in their approach and are, as a result, difficult to compare. As ruminants in most production systems are fed ad libitum, this is also the most appropriate intake level at which to estimate energetic efficiency. Analyses of older as well as more recent data suggest that ad libitum feeding (i) abolishes the effects of diet quality on energetic efficiency (almost) completely, (ii) abolishes the differences between lactating and non-lactating animals (almost) entirely and (iii) results in overall energetic efficiencies that are always close to 0.6. The paper argues that there is now sufficient information to develop an international energy evaluation system for ad libitum fed ruminants. Such a system should (i) unify ME and NE systems, (ii) avoid the systematic bias and large errors that can be associated with current systems (iii) be simpler than current systems and (iv) have as a starting point a constant efficiency of ME utilisation, with a value of around 0.6. The remarkably constant efficiency of ME utilisation in ad libitum fed ruminants could be the result of energetic efficiency as well as feed intake regulation being affected by the same variables or of a direct role of energetic efficiency in feed intake regulation. Models to predict intake on the basis of the latter hypothesis are already available for non-reproducing ruminants but remain to be developed for reproducing animals. Keywords: energy evaluation systems, energy requirements, efficiency of ME utilisation ImplicationsThere are currently many different national energy evaluation systems for ruminants, which makes comparisons across borders problematic. The paper suggests that these different systems could be unified by taking ad libitum feeding, that is, the dominant on-farm feeding system, as a starting point. The presented analyses of older as well as more recent data show that the overall efficiency of ME utilisation in ad libitum fed ruminants is (i) virtually independent of feed quality characteristics, (ii) not essentially different between lactating and non-lactating ruminants and (iii) close to a value of 0.6. Using a single value for overall energetic efficiency in ad libitum fed ruminants (i) considerably simplifies existing energy evaluation systems, (ii) avoids the use of different national energy evaluation systems and abo...

The changes in behavior associated with a (subclinical) acute and a chronic health challenge were investigated to assess their potential value for the development of an early disease detection system in beef cattle. The hypothesis was that acute challenges would lead to acute but transient changes in behavior, whereas the converse would be the case during chronic challenges, with changes taking longer to develop, but being more persistent. For this purpose, Holstein-Friesian beef bulls were challenged either with a repeated lipopolysaccharide (LPS) intravenous bolus given at 3 increasing doses over the course of 5 d, or with a single dose of the abomasal parasite Ostertagia ostertagi, acting as models of acute and chronic challenge respectively. A third unchallenged group acted as controls. Fecal and blood samples were taken regularly and analyzed for fecal egg counts (FEC), pepsinogen concentration and LPS antibodies. A sensor was fitted to the front leg of each bull to record activity and posture. Video recordings were taken to monitor drinking and feeding behavior. Antibodies to LPS were detected only after the third LPS challenge. Fecal egg counts were detected 3 wk post infection, and pepsinogen increased roughly at the same time in parasitized bulls. Body weight of parasitized animals was reduced relative to controls after 17 d post infection (P < 0.001), whereas there was no difference in performance between the LPS and control animals (P > 0.05). Effects of LPS on behavior lasted only for a few hours, presenting themselves as reduction in activity approximately 10 h after the first challenge (P = 0.057). The clearest behavioral changes due to parasitism were on posture. Parasitized animals had less frequent (P = 0.003), but longer lying episodes (P = 0.038) than controls. Once established, these changes persisted for 30 d post infection. However, there was no treatment effect on overall activity, measured by the number of steps taken or on total lying time (P > 0.05). Frequency of feeding and drinking episodes and their duration were not affected by health challenge (P > 0.05); however there was an increase in average duration of feeding (P = 0.013) for the parasitized animals. Even though the parasite challenge had significant effects on several aspects of behavior, these may be considered too subtle to be useful indicators of disease; however when used with other measurements, they may prove helpful for the early detection of disease in beef cattle.

Better understanding of how animals regulate their intake may be gained by analysis of feeding behaviour. This is often recorded in terms of feeding events, e.g. visits to feeders, which can be clustered into meals. This enables calculation of the probability of animals starting a meal in relation to time since the last meal, which is thought to give insight into food intake regulation. Starting probabilities are often calculated with pooled data but recent work suggests that pooling may strongly affect conclusions.In this study we analysed feeding behaviour of cows to investigate how previous conclusions about feeding behaviour may have been affected by pooling. Using parameters derived from experimental data, we constructed simulation models to further explore under what circumstances pooling, either across day and night or across individuals, could affect the interpretation of starting probabilities. Data were simulated to explore the consequences of pooling as either the proportion of meals occurring during the day or the individual variation in their mean number of meals per 24 h changed. Simulation allowed us to extend the analysis of the consequences of pooling for the interpretation of starting probabilities.Analysis of experimental data, collected with 16 dairy cows, showed that they ate a mean of six meals per 24 h. Individual variation resulted in a proportional CV of the individual mean number of meals per 24 h of 0·14. Cows ate a mean proportion of 0·59 of their meals during the day. Analysis of experimental data suggested that pooling, conducted in previous studies, has probably led to a quantitative underestimation of the increase in starting probability with time since the last meal but not a qualitative misinterpretation of the direction of change in the starting probability.Simulation studies showed that pooling had no serious consequences when the mean number of meals per 24 h, or the variation about this mean, was low. However, as the number of meals per 24 h and variation increased, pooling led to conclusions that may wholly misrepresent both magnitude and direction of the change in starting probabilities calculated separately for the individuals or for day and night. This may explain why the results of some published studies seem not to agree with biological principles of food intake regulation.

Introduction Information on (changes in) standing and lying behaviour can be used for oestrus detection and early diagnosis of health problems, to evaluate welfare consequences of changes in housing and management and to investigate the underlying animal motivation for these behaviours. A data set on lying and standing behaviour was collected from cows with IceTag™ sensors (IceRobotics, South Queensferry, UK) fitted to their legs. Our aims were (a) to investigate whether this behaviour was bouted, (b) to estimate bout criteria if required and (c) to test the hypotheses that (i) the probability of cows standing up would increase with lying time and (ii) the probability of cows lying down would increase with standing time.