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Sheng, Kehan; Foris, Borbala; Krahn, Joseph; Weary, D.M; von Keyserlingk, M.A.G 2023-12-15 Dominance hierarchies are known for mitigating conflicts and guiding priority of access to limited resources in gregarious animals. The dominance hierarchy of dairy cows is typically constructed using agonistic interactions, usually monitored at the feed bunk right after fresh feed delivery when competition is high resulting in numerous interactions. Yet, the outcome of agonistic interactions under time of high competition time may be more influenced by cows’ high valuation of fresh feed than their intrinsic dominance attributes. Thus, the dominance hierarchy constructed using agonistic interactions under high versus low competition times might differ. The aim of this study was to test how the structure of the dominance hierarchy changes in relation to different levels of competition. We monitored a dynamically changing group of 48 lactating dairy cows over 10 mo with 6 cows exchanged every 16 d, totally 159 cows. We used a validated algorithm to continuously detect the actor and reactor of replacement behaviors as cows competed for feed. We calculated feeder occupancy, the percentage of occupied feed bins, to characterize competition at the moment of each replacement, and created 25 corresponding dominance hierarchies using Elo ratings for occupancy levels ranging from 13% to 100%. With each 10% rise in feeder occupancy, hierarchy steepness fell by 0.02 (R2 = 0.96) and two-way dyads rose by 1.3% (R2 = 0.84). The win rate of the dominant cow within dyads declined with increased feeder occupancy (y = -0.11x -0.21, P < 0.001). Our findings provide evidence that there is noticeable variation in inferred hierarchies based on the competition context, with high competition flattening the hierarchy as subordinate animals succeed more in replacing others in order to gain feed access. This finding underscores that during heightened competition, the valuation of resources impacts agonistic behaviors and the subsequently constructed dominance hierarchy more than the individual's intrinsic dominance attributes. We recommend that researchers avoid using agonistic interactions occurring immediately after fresh feed delivery to establish dominance hierarchies. We also urge researchers to differentiate agonistic interactions based on context when constructing dominance hierarchies to draw inferences on animal behavior, cognition and health.
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Foris, Borbala; Sadrzadeh, Negar; Krahn, Joseph; Weary, D.M; von Keyserlingk, M.A.G 2023-02-22 Mechanical brushes are often provided on dairy farms to facilitate grooming. However, current brush designs do not provide data on their use and little is known about the effects of group size and placement of brushes within the pen. The objectives of this study were to automatically detect brush use in cow groups and investigate the influence of (1) group size and the corresponding cow-to-brush ratio and (2) brush placement in relation to the lying stalls and the feeding and drinking areas. We measured brush use in groups of 60, 48, 36, and 24 cows with the brush placed either in the alley adjacent to the feed bunk and water trough or in the back alley. Cows used the brush longer when placed in the feed/water alley compared to when placed in the back alley. Average brush use per cow increased when cows were housed in smaller groups but the brush was never in use more than 50% of the day regardless of group size. We conclude that brush use in-creases when availability is increased and when the brush is placed closer to feed and water.
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Foris, Borbala; Lecorps, Benjamin; Krahn, Joseph; Weary, D.M; von Keyserlingk, M.A.G 2021-11-17 An animal’s social position within a group can influence its ability to access essential resources such as food or a lying area, but little is known about how social position affects the ability to express what are arguably less important but still rewarding behaviors, such as grooming. We set out to assess if dominance measured at the feeder is associated with increased use of a mechanical brush. Over a 2-year period, 161 dry cows were enrolled in a dynamically changing group of 20 individuals with access to a mechanical brush. We determined dominance using agonistic behaviors at the feeder and retrospectively analyzed brush use for the 12 most, and 12 least dominant individuals during the week before calving. Cows that were more dominant at the feeder used the brush more, especially during peak feeding times. Agonistic interactions at the brush did not differ between dominants and subordinates and were not related to brushing duration. These findings indicate that social position, calculated using competition for feed, affects mechanical brush access such that subordinates use the brush less than dominant cows independent of competition or time of day.
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Foris, Borbala; Vandresen, Bianca; Sheng, Kehan; Krahn, Joseph; Weary, D.M; von Keyserlingk, M.A.G 2023-11-20 Water is an essential resource for dairy cattle, and in some circumstances cattle will compete with one another to gain access to water. Here we applied a Bayesian-based, Elo-rating method to assess the winning probabilities of 87 cows housed in a dynamic group and compared the resulting social hierarchies based on their steepness. We identified a hierarchy at the drinker with a steepness of 0.55±0.02 whereas the hierarchy detected at the feeder during the same time period was less steep (0.45±0.02), indicating smaller average differences between the winning probabilities of cows when competing for feed compared to competing for water. Individual cows’ winning probabilities at the feeder and drinker were moderately correlated (rs=0.55, P<0.001). However, cows at both the lower and upper ends of the hierarchy demonstrated a consistent alignment. We compared drinker hierarchies between periods with THI above and below 72 and found similar steepness (0.54±0.03 and 0.56±0.03 respectively) and the individual winning probabilities of cows were highly correlated between hot and normal periods (rs=0.87, P<0.001). Individual drinking behaviour was also associated with the drinker hierarchy, cows with higher winning probability had lower average daily visit frequency (hot: rs=-0.40, P<0.01, normal: rs=-0.33, P<0.01) and higher average daily water intake (hot: rs=0.38, P<0.01, normal: rs=0.37, P<0.01). We also found evidence that cows differ in when they drink, depending on their winning probability; less successful cows shifted their drinking times to before or after the visit peak after milking. Automatically identifying cows with consistently high or low winning probabilities using drinkers may inform grouping decisions and water provision on farms.
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Krahn, Joseph; Azadian, Amin; Cavalli, Camilla; Miller, Julia; Protopopova, Alexandra 2024-01-15 Spatial judgement bias tests (JBTs) can involve teaching animals that a bowl provides a reward in one location but does not in another. The animal is then presented with the bowl placed between the rewarded and the unrewarded locations (i.e., ambiguous locations) and their latency to approach reflects expectation of reward or ‘optimism’. Some suggest that greater ‘optimism’ indicates better welfare. However, performance in JBTs may also indicate learning history independently from welfare determinants. We hypothesized that dogs’ ‘optimism’ in a follow-up JBT may be impacted by a learning treatment. Pet dogs (n=16) completed a JBT pre-treatment, a trial-based learning treatment, and a JBT post-treatment. During the JBT, dogs were presented with 5 locations: 1 rewarded, 1 unrewarded, and 3 ambiguous (all unrewarded). Dogs were randomly assigned to a trial-based learning task—a nose-touch to the palm of the hand. In Discrimination (n=8), the dog was presented with two hands in each trial, only rewarded for touching one specific hand. In Generalization (n=8), dogs were presented with one hand per trial in alternating sequence and were yoked to dogs in the Discrimination to receive the same number of rewarded and unrewarded trials (to control for possible frustration). Using a linear mixed model including dog identity as a random effect, we found no difference in the change in approach latency to the ambiguous locations between the dogs across treatments (P=0.97). ‘Optimism’ as measured in this JBT may not be sensitive to the type of training used in our study.
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Krahn, Joseph; Foris, Borbala; Sheng, Kehan; Weary, D.M; von Keyserlingk, M.A.G 2024-01-02 Group-housed cattle sometimes engage in agonistic competitive behavior over resources such as feed, which can negatively affect aspects of welfare. Little is known about how contextual factors such as group size influence agonistic behavior. We explored the frequency of agonistic interactions at the feeder when cattle were housed in different sized groups. We also explored the consistency of the directionality of agonistic interactions in dyads and of the number of agonistic interactions initiated by individuals across the group sizes. Four replicates of 50 cows each were assessed in two group-size phases. In Phase 1, cows were kept in one group of 50. In Phase 2, these same cows were divided into 5 groups of 10, maintaining stocking density (i.e., ratio of animals to lying stalls and feed bunk spaces). We measured agonistic replacements (i.e., interactions that result in one cow leaving the feed bin and another taking her place) at an electronic feeder using a validated algorithm. We used these data from Phase 1 to calculate individual Elo-ratings (a type of dominance score). Cows were then categorized into 5 dominance categories based upon these ratings. To ensure a consistent Elo-rating distribution between phases, 2 cows from each dominance category were randomly assigned to each small group of 10 cows. The mean±SE number of replacements per cow was similar regardless of whether the cows were housed in groups of 50 (34.1±2.4) or 10 (31.1±5.0), although the groups of 10 were more variable. Further, 81.5±5.2% of dyads had the same directionality across group sizes and individuals were moderately consistent in the number of replacements they initiated (ICC=0.62). These results indicate that the relationship between group size and agonistic behaviour is complex; we discuss these challenges and suggest new avenues for further research.

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