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International audience; In ruminants, feeding behaviour variables are parameters involved in feed efficiency that show variation among individuals. This study aimed to evaluate during the first two production cycles in ruminants the repeatability of feed intake pattern, which is an important aspect of feeding behaviour. Thirty-five dairy goats from Alpine or Saanen breeds were housed in individual pens at four periods (end of first gestation, middle of first and second lactations and middle of second gestation which is also the end of first lactation) and fed a total mixed ration (TMR) ad libitum. Individual cumulative dry matter intake (DMI) was automatically measured every 2 min during the last 4 days of each period. Feed intake pattern was characterized by several measures related to the quantity of feed eaten or to the rate of intake during the 15 h following the afternoon feed delivery. Two main methods were used: modelling cumulative DMI evolution by an exponential model or by a segmentation-clustering method. The goat ability to sort against dietary fibre was also evaluated. There was a very good repeatability of the aggregate measures between days within a period for a given goat estimated by the day effect within breed and goat, tested on the residual variance (P > 0.95). The correlations between periods were the highest between the second and either the third or fourth periods. With increasing age, goats sorted more against the fibrous part of the TMR and increased their initial rate of intake. Alpine goats ate more slowly than Saanen goats but ate during a longer duration. Principal component analysis (PCA) was performed on all the aggregate measures of feed intake patterns. The factor score plots generated by the PCA highlighted the opposition between the different measures of feed intake patterns and the sorting behaviour. The projection of the animals on the scoring plots showed a breed effect and that there was a continuum for the feed intake pattern of goats. In conclusion, this study showed that the feed intake pattern was highly repeatable for an animal in a given period and between periods. This means that phenotyping goats in a younger age might be of interest, either to select them on feeding behaviour and choose preferentially the slow eaters or to adapt the quantity offered and restrict feed delivery to the fast eaters in order to increase feed efficiency and welfare by limiting the occurrence of acidosis, for example.

An understanding of the processes involved in grazing behaviour is a prerequisite for the design of efficient grassland management systems. The purpose of managing the grazing process is to identify sward structures that can maximize animal forage daily intake and optimize grazing time. Our aim was to evaluate the effect of different grazing management strategies on foraging behaviour and herbage intake by sheep grazing Italian ryegrass under rotational stocking. The experiment was carried out in 2015 in southern Brazil. The experimental design was a randomized complete block with two grazing management strategies and four replicates. The grazing management treatments were a traditional rotational stocking (RT), with pre- and post-grazing sward heights of 25 and 5 cm, respectively, and a ‘Rotatinuous’ stocking (RN) with pre- and post-grazing sward heights of 18 and 11 cm, respectively. Male sheep with an average live weight of 32 ± 2.3 kg were used. As intended, the pre- and post-grazing sward heights were according to the treatments. The pre-grazing leaf/stem ratio of the Italian ryegrass pasture did not differ between treatments (P > 0.05) (~2.87), but the post-grazing leaf/stem ratio was greater (P < 0.001) in the RN than in the RT treatment (1.59 and 0.76, respectively). The percentage of the non-grazed area was greater (P < 0.01) in post-grazing for RN compared with RT treatment, with an average of 29.7% and 3.49%, respectively. Herbage nutritive value was greater for the RN than for the RT treatment, with greater CP and lower ADF and NDF contents. The total time spent grazing, ruminating and resting did not differ between treatments (P > 0.05), with averages of 439, 167 and 85 min, respectively. The bite rate, feeding stations per min and steps per min by sheep were greater (P < 0.05) in the RN than in the RT treatment. The grazing time per hour and the bite rate were greater (P < 0.05) in the afternoon than in the morning in both treatments. The daily herbage intake by sheep grazing Italian ryegrass was greater (P < 0.05) in the RN than in the RT treatment (843.7 and 707.8 g organic matter/sheep, respectively). Our study supports the idea that even though the grazing time was not affected by the grazing management strategies when the animal behaviour responses drive management targets, such as in ‘Rotatinuous’ stocking, the sheep herbage intake is maximized, and the grazing time is optimized.

In intensive feeding systems, competition may be high and social dominance may affect animal performance by changing dry matter intake (DMI) and behavioral time budgets. If competition level is maintain over time, the strategies developed by heifers of different social status are expected to differ. Thus, the aim of this study was to compare individual DMI, intake rate and eating, ruminating, lying and standing behaviors in dominant (DOM) and subordinate (SUB) pre-pubertal dairy heifers in a model study implying continuous competitive situations. A total of 16 Holstein and Jersey×Holstein pre-pubertal heifers (251±10 days old, weighing 208±14 kg; mean±SEM) were allocated into eight homogeneous dyads. Each dyad was maintained during 120 days (day 0=beginning of measurements) in pens, and received a total mixed ration from one feeder/dyad. The DOM and SUB heifers was determined (day 0, twice during the first month of the experiment and every month afterwards) by observation of the winner in agonistic interactions in each dyad after the feed was supplied. The general activity pattern (eating, ruminating, lying and standing) of each heifer was recorded by direct instantaneous scan-sampling, every 10 min for 12 h, in 7 days (days 1, 21, 35, 60, 75, 100 and 120). Individual DMI was estimated with the double marker technique, in three intervals (I=days 17-26; II=days 78-87 and III=days 112-120), while estimated intake rate (kg/min) was calculated for each interval as the DMI per total eating time. After the experiment was concluded, data of the first 5 and the last 6 h of the 12 h scan-sampling (related to the moment the feed was supplied) was grouped according to the moments of greater and lesser competition for feed on each day. During the first 5 h, where competition was expected to be highest, no differences in eating behavior were found between heifers of different social status, but DOM heifers spent more time ruminating and lying than SUB heifers, while SUB spent more time standing than DOM heifers. No differences were found on DMI between DOM and SUB, but SUB ate at a faster rate on interval II compared with DOM heifers. In conclusion, in this model study of heifer dyads, SUB heifers had greater intake rate with no differences in feed intake, spent less time ruminating and lying, and more time standing than DOM heifers during the first hours after feed delivery.

Pigs are housed in groups during the test period. Social effects between penmates may affect average daily gain (ADG), backfat thickness (BF), feed conversion rate (FCR), and the feeding behaviour traits of pigs sharing the same pen. The aim of our study was to estimate the genetic parameters of feeding behaviour and production traits with statisticalmodels that include social genetic effects (SGEs). The data contained 3075 Finnish Yorkshire, 3351 Finnish Landrace, and 968 F1-crossbred pigs. Feeding behaviour traits were measured as the number of visits per day (NVD), time spent in feeding per day (TPD), daily feed intake (DFI), time spent in feeding per visit (TPV), feed intake per visit (FPV), and feed intake rate (FR). The test period was divided into five periods of 20 days. The number of pigs per pen varied from 8 to 12. Two model approaches were tested, i.e. a fixed group size model and a variable group size model. For the fixed group size model, eight random pigs per pen were included in the analysis, while all pigs in a pen were included for the variable group size model. The linear mixed-effectsmodel included sex, breed, and herd*year*season as fixed effects and group (batch*pen), litter, the animal itself (direct genetic effect (DGE)), and penmates (SGEs) as random effects. For feeding behaviour traits, estimates of the total heritable variation (T-2 +/- SE) and classical heritability (h(2) +/- SE, values given in brackets) from the variable group size model (e.g. period 1) were 0.34 +/- 0.13 (0.30 +/- 0.04) for NVD, 0.41 +/- 0.10 (0.37 +/- 0.04) for TPD, 0.40 +/- 0.15 (0.14 +/- 0.03) for DFI, 0.53 +/- 0.15 (0.28 +/- 0.04) for TPV, 0.66 +/- 0.17 (0.28 +/- 0.04) for FPV, and 0.29 +/- 0.13 (0.22 +/- 0.03) for FR. The effect of social interaction was minimal for ADG (T-2 = 0.29 +/- 0.11 and h(2) = 0.29 +/- 0.04), BF (T-2 = 0.48 +/- 0.12 and h(2) = 0.38 +/- 0.07), and FCR (T-2 = 0.37 +/- 0.12 and h(2) = 0.29 +/- 0.04) using the variable group size model. In conclusion, the results indicate that social interactions have a considerable indirect genetic effect on the feeding behaviour and FCR of pigs but not on ADG and BF. (C) 2020 The Authors. Published by Elsevier Inc. on behalf of The Animal Consortium.

Feed intake behavior was studied between 9 weeks of age and slaughter in a total of 36 gilts, 32 immunocastrates, 33 surgically castrated barrows and 33 boars from 36 litters. Consequences for the concentration of substances contributing to off odor of pork (skatole, indole) were evaluated. Animals were kept in groups of 12 pigs of the same sex and treatment and fed ad libitum (13.4 MJ ME, 17% CP, 1.1% lysine). Individual feed intake behavior was recorded continuously by an electronic feeder. Immunocastration was carried out with two injections of Improvac with at least 4 weeks between both injections (1st: 12 to 17 weeks of age, 2nd: 19 to 21 weeks of age). Feed intake/day increased from an average of 0.91 ± 0.02 kg/day up to 3.15 ± 0.04 kg/day before slaughter. This increase was associated with a 50% reduction in the number of meals/day (from 15.8 ± 0.44 to 7.2 ± 0.29 meals/day). The larger meal sizes resulted from an increase in both, the duration of feed intake/meal and the feed intake rate (g/min). In addition, sex and treatment differences were observed: Feed intake in boars was lower than in all other groups due to a reduction in the number of meals/day and in the time spent feeding/day. In females, time spent feeding/day was quite similar to boars, but resulted from a higher number of meals of shorter duration. Barrows had a significantly higher feed intake because of a higher number of meals/day resulting in more time spent feeding/day. The feed intake rate was similar in boars, gilts and barrows and showed an increasing trend during the study, starting from about 15 g/min up to four times the amount. Immunocastration affected feed intake behavior severely, especially the meal size increased dramatically because of higher feed intake rate, which exceeded that of all other groups by 25% at the end of the study. The number of meals/day was not influenced by immunocastration and was almost identical to that of boars. Highest skatole concentrations were measured in fat of boars, whereas indole concentrations were higher in immunocastrates than in all other groups. In gilts and barrows, skatole concentrations were related to growth rate. Additionally, the feeding rate was an important factor explaining the variability in skatole/indole concentrations in adipose tissue. The physiological mechanisms however need further clarification.