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Investigating the effect of pen shape and pen size on group flight distance of extensively managed ewes
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Applied Animal Behaviour Science journal homepage: www.elsevier.com/locate/applanim
Investigating the effect of pen shape and pen size on group flight distance of extensively managed ewes Samantha R. Cramera, Carolina A. Munoza, David M. McGillb, Maxine Ricea, Rebecca E. Doylea,* a b
Animal Welfare Science Centre, Level 2, 21 Bedford St, University of Melbourne, North Melbourne, 3051 VIC, Australia Faculty of Veterinary and Agricultural Sciences, 250 Princes Highway, The University of Melbourne, Werribee, 3030 VIC, Australia
A R T I C LE I N FO
A B S T R A C T
Keywords: Animal welfare assessment Animal-based indicator Fear Flight zone Human-animal relationship
This study investigated the effect of pen shape and pen size on the group flight distance of extensively managed ewes, and how flight distances of individual ewes compared when recorded in group and isolated settings. Within eight groups of 25 sheep, six focal animals were randomly selected (N = 48 ewes). Over four days, groups were placed in four different sized and shaped pens and flight distances (m) of focal animals were recorded. Pens designs were small rectangle (3.3 m x 7.2 m), medium rectangle (4.8 m x 5.8 m), large rectangle (11 m x 19.6 m) and curved/concave (with 31.5 m perimeter). Following a previously validated protocol, flight distance (m) was also recorded when focal sheep were physically isolated from conspecifics. There was no association between the isolated flight distance and group flight distance of focal animals (n = 39, r(37) = 0.03, P = 0.83). Group flight distance was significantly affected by pen design (P < 0.001), being greater in large pens and smaller in small pens. To account for these pen effects, group flight distance was adjusted and analysed as a proportion of the largest dimension of each pen. To test this mathematical adjustment, pen and other variables predicted to have an influence on adjusted group flight distance were analysed as fixed effects in linear mixed models. A statistically significant Day x Pen interaction was found (F9,84 = 3.01, P < 0.004), although post-hoc pairwise comparisons showed that this interaction had no clear pattern across days or pens. The simple mathematical adjustment and statistical modelling made group flight distances comparable by accounting for day and pen effects. These results suggest that analysing group flight distance as a proportion of the pen in future welfare assessments will enable comparisons to be made between sites.
1. Introduction The human-animal relationship (HAR) represents the direct impact farmer or stockperson (terms used interchangeably here) attitudes and behaviours have on animal fear, stress, welfare and productivity (Hemsworth and Coleman, 2011). The HAR of extensively managed sheep involves neutral or aversive stockperson handling on an infrequent basis (Dwyer, 2009). This gives animals little opportunity to habituate to human contacts leading to stress and fear when they do occur (Turner and Dwyer, 2007). Human-sheep relationship indicators are required to assess how variations between farmer handling and positive behaviours may result in less fear and stress and a calmer behavioural response (Hemsworth and Coleman, 2011). Flight distance tests that ascertain the level of fear and stress experienced by sheep in response to an approaching human (Grandin and
Deesing, 2014) can be used as HAR indicators in welfare assessments. Hargreaves and Hutson (1990) conducted an individual flight distance test where ewes were isolated from conspecifics, placed in a start box and released into a race as a human approached from the opposite end. This validated test is practical for on-farm welfare assessments because it relies on single race infrastructure that is relatively consistent across farms, allowing for between site comparisons. However, as sheep are a highly social species, individual tests are assumed to have little relevance when assessing extensively managed sheep because the fear experienced by single sheep may not reflect fear of the flock, and the stress of social isolation may confound results (Boivin et al., 2003; Waiblinger et al., 2006). For these reasons, group flight distance tests may be more suitable when assessing extensively managed sheep as social isolation is nullified. Group flight distance may be determined by measuring the flight
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Corresponding author at: Animal Welfare Science Centre, Faculty of Veterinary and Agricultural Sciences, Level 2, 21 Bedford St, The University of Melbourne, North Melbourne, Victoria 3051, Australia. E-mail addresses: [email protected] (S.R. Cramer), [email protected] (C.A. Munoz), [email protected] (D.M. McGill), [email protected] (M. Rice), [email protected] (R.E. Doyle). https://doi.org/10.1016/j.applanim.2019.104887 Received 13 December 2018; Received in revised form 13 October 2019; Accepted 23 October 2019 0168-1591/ Crown Copyright © 2019 Published by Elsevier B.V. All rights reserved.
Please cite this article as: Samantha R. Cramer, et al., Applied Animal Behaviour Science, https://doi.org/10.1016/j.applanim.2019.104887
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Fig. 1. Isolated flight distance test: sheep were physically isolated from conspecifics and released from the start box and traversed the race before entering the post-test pen. Following the sheep’s exit from the start box, the observer approached from the start point until a flight response was observed and the flight distance (m) was recorded. This test was repeated on all 48 focal sheep.
inter-observer variation. Ewes were kept in four paddocks in between tests. In order to do this, the same two groups were combined overnight and then redrafted into their groups of 25 each day before testing.
distance of an individual ewe when within a group setting (Napolitano et al., 2011) or by recording the flight distance at the flock level, as has been proposed in the AWIN (2015) welfare assessment protocol for sheep. This protocol presents a practical option for assessing the human-sheep relationship, but there is no formal definition or criteria to determine group flight distance. Furthermore, there is no published evidence of this test being standardised for uncontrolled variables that inherently exist between farms, such as pen design, testing locations, method of approach, flock size and noise. The impact of different enclosures may confound results, as work by Napolitano et al. (2011) indicated that pen design and space allowances of testing facilities were likely to play a role in the expression of fear and flight distance. Additionally, sheep managed in extensive settings, including Australian farming systems, naturally display large flight zones (Grandin, 2008). This makes understanding the effect of pen design on group flight distance even more important because the impact of flight zones that exceed testing locations is unknown. We hypothesised that differences in pen design confound group flight distance test results used in welfare assessments. The present study aimed to investigate the effect of pen shape and pen size on the group flight distance of extensively managed ewes, using a standardised group flight distance test adapted from the Napolitano et al. (2011) and AWIN (2015) protocols. Mathematical adjustments to account for the pen differences were also tested. The Hargreaves and Hutson (1990) individual flight distance test was included to examine how flight distances of individual ewes compared when recorded in group and isolated settings.
2.2.1. Isolated flight distance test This test was used to assess the flight distance of focal sheep when physically isolated from conspecifics, and was adapted from the previously validated individual flight distance test by Hargreaves and Hutson (1990). Behavioural responses to an approaching human were tested using a start box and a race located in the sheep yards. The portable start box was a standard weighing crate with enclosed wooden walls (1.27 m x 0.52 m x 0.81 m) that was placed and opened to the front of the race (18.5 m x 1.1 m) (Fig.1). Markers were placed at 2 m increments along the race. Three GoPro HERO4 Silver edition cameras (GoPro, Inc., San Mateo, California, U.S.) continuously recorded the start box and race during the test. Test focal animals were visually isolated from conspecifics during the test, but audible range was maintained. All tests were conducted over one day. For this test, the six focal animals from each of the eight groups (N = 48) were drafted and tested once individually. Ewes were given 10 min to settle in the pre-test pen before behavioural testing commenced. Test sheep were individually caught by a handler and placed in the start box facing the doors. The ewe was given 30 s to settle before the start box doors were released. When the ewe exited the start box, the observer approached the ewe from the opposite end at the start point (Fig.1), at a pace of 1 step/s while facing the start box. The observer looked towards the ewe and approached with arms against the torso. The observer stopped approaching when a flight response was observed, which was defined as the point at which the ewe began to run past the observer (Hargreaves and Hutson, 1990). The isolated flight distance (m) was recorded as the distance between the observer’s feet and the ewe’s front hooves at the time of flight response. The markers were used as a guide to estimate the isolated flight distance and this was obtained post-hoc from the GoPro footage. The test period was over when the ewe entered the post-race pen.
2. Materials and methods This project received approval from the University of Melbourne Faculty of Veterinary and Agricultural Sciences Animal Ethics Committee (Ethics ID 1714127). 2.1. Animals & husbandry Two hundred single-bearing Merino ewes (aged 2–4 years) in early pregnancy (1–2 months gestation) were randomly selected for this study from a large flock of 3000 breeding ewes. The flock was raised extensively in a year-round outdoor system and managed in paddocks with limited human contacts. For the duration of the study, the 200 ewes were housed in paddocks in accordance with the University of Melbourne’s farm management protocol. The paddocks were in close proximity to the sheep yards and testing locations to limit daily handling.
2.2.2. Group flight distance test This test was used to assess the flight distance of focal sheep in a group situation using methodology by Munoz et al. (2018) which was adapted from existing group flight distance tests by Napolitano et al. (2011) and the AWIN (2015) welfare assessment protocol for sheep. Flight distance to an approaching human were tested using four constructed pens within the sheep yards. The dimensions were adapted from the most common pen designs that were observed across 32 Victorian farms during the larger project that applied the same group flight distance test (Munoz et al., 2018). The small rectangle (SR) measured 3.3 m x 7.2 m, the medium rectangle (MR) measured 4.8 m x 5.8 m, the large rectangle (LR) measured 11 m x 19.6 m and the curved/concave (C) measured a perimeter of 31.5 m (Fig. 2). Test groups were visually isolated from other groups during the test, but audible range was maintained. Tests were conducted over four days with each group being tested in one pen per day. All eight groups were tested in each of the four pens using a cross-over design, to ensure that the repeated measures were balanced for all pen designs. Flight distance was recorded for the six focal animals within each group (N = 192).
2.2. Experimental design, procedure and behaviour assessments Ewes were randomly divided into eight groups of 25 animals, identified with washable spray marker sprayed onto backs, and remained in these same groups for the duration of the experiment. Within each group of 25 ewes, six focal animals were randomly selected and individually identified with washable spray marker sprayed onto backs, and they remained as focal animals for all behavioural testing. The same researcher (SRC) conducted all flight distance tests to eliminate 2
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Fig. 2. Group flight distance test: groups of sheep were allocated to constructed pens of different shape and size. The observer started at the start point and approached a focal animal until a flight response was observed and the flight distance (m) was recorded. This process was repeated for all six focal animals within each group.
distance was also analysed as a proportion of the pen, as opposed to an absolute value. To adjust for these differences, the maximum dimension of each pen (diagonal; exact or estimated) was obtained and used to calculate the group flight distance as a proportion of the dimension length. The diagonal was the largest flight distance a sheep could establish between itself and the observer, positioned at the start point. The diagonal dimension was calculated exactly as 7.9 m for SR, 7.5 m for MR, 22.5 m for LR and estimated as 11.1 m for C. Results are reported as Mean ± Standard Deviation. Variables that were predicted to have an influence on adjusted group flight distance were analysed as fixed effects in linear mixed models and tested for statistical significance during preliminary analyses. Variables that had no statistically significant effect were removed from the final linear mixed model. Pen was included to investigate the effect of pen design. To investigate the effect of environmental noise, decibels (minimum, average and maximum) were included, however all three variables overfit linear mixed models when analysed as interactions and were subsequently removed from the final analyses. To detect intra-observer bias/drift and habituation or sensitisation of focal sheep, we considered variables (of varying complexity) that examined change in the adjusted group flight distances over time. These variables were day, time interval (AM or PM), the order of focal sheep tests within their respective group test (N = 6), the total order of focal sheep tests (N = 192), the order of group tests within days (N = 8) and the total order of group tests (N = 32). The total order of focal sheep tests, the order of group tests within days and the total order of group tests overfit the linear mixed models and were subsequently removed from the final analyses. The final linear mixed model, used for all subsequent analyses, incorporated pen and day as fixed factors. Focal sheep nested within group was incorporated as a random effect but was found to overfit the linear mixed model. Instead, group was analysed as a random effect to account for variations between groups. 2.3.2.2.1. Final linear mixed model. Adjusted group flight distance = Pen x Day + Group Post-hoc pairwise comparisons for pen and day were conducted using Least Square Means Differences and the Tukey method for p-value adjustment. Results are reported as Least Square Means ± Standard Error of the Least Square Means.
The group was moved to the pen and given 10 min to settle before the test started. The observer then entered the pen at the start point (Fig. 2) and walked anticlockwise around the perimeter at a rate of 1 step/s, with arms beside the torso and gaze held at eye level. After the observer returned to the start point, the observer waited for the group to settle, which was defined as the point at which the whole group exhibited no mobile movement or displacements for at least 3 s. The observer randomly selected one of the six marked focal animals and approached the ewe at a pace of 1 step/s. The observer looked towards the ewe and approached with arms against the torso. The observer stopped approaching when a flight response was observed, which was defined as the point at which the ewe stepped away/withdrew in an attempt to re-establish the flight zone. A surveyor wheel was used to measure the group flight distance, and this was obtained immediately after the flight response. The group flight distance (m) was recorded as the distance between the observer’s feet and the middle of the ewe’s back at the time of flight response. The observer then returned to the start point and the same process was performed on the remaining focal animals in the group. As noise was an uncontrolled factor, the environmental noise within the sheep yards was recorded during the tests by measuring decibel minimums, averages and maximums using the mobile phone application Decibel 10 for iOS version 5.3.3 (Skypaw Co Ltd, 2017). 2.3. Statistical analysis All statistical analyses were conducted using R Version 3.6.0 (RStudio Team, 2018). A statistical significance value of P < 0.05 was used for all statistical analyses. A stepwise approach using graphical representations was employed to inform decisions when assessing the normality of the data distributions, and residuals of outputs. Bartlett’s test was conducted to assess the homogeneity of variances. 2.3.1. Isolated flight distance test During the test, it was clear that the reactions of sheep varied after release from the start box. The reaction type was binary, with some sheep displaying a flight response after viewing the observer and others starting flight as soon as the start box opened and before viewing the observer. Sheep that performed the latter response have been categorised as having a ‘generalised fear response’. Results are presented as Mean ± Standard Deviation.
2.3.3. Isolated and group flight distance test comparisons ‘Generalised fear response’ sheep were excluded from this analysis. To investigate the relationship between focal animal behaviour within the isolated and group flight distance test, a Pearson’s correlation test was performed between each focal animals’ isolated flight distance and average adjusted group flight distance. Correlation coefficients of 0.30.49 were deemed moderate, and coefficients from 0.50 were deemed strong (Cohen, 2013).
2.3.2. Group flight distance test 2.3.2.1. Raw group flight distance. To investigate the effect of pen design on group flight distance, raw data was analysed using a linear model with unequal variances. Post-hoc pairwise comparisons were conducted using a Fisher Least Significant Differences test. Results are presented as Mean ± Standard Deviation. 2.3.2.2. Adjusted group flight distance. To account for differences in flight distance that were influenced by pen shape and size, group flight 3
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Fig. 3. Boxplot with individual data points comparing the distribution of raw group flight distance measures between and within pens. Raw group flight distance was significantly different (P < 0.05) between all four pen designs.
3. Results
3.3. Isolated and group flight distance test comparisons
3.1. Isolated flight distance test
There was no association between the isolated and average adjusted group flight distances of focal animals (n = 39, r(37) = 0.03, P = 0.83).
A total of 39 sheep showed a flight response after viewing the observer with flight distances ranging from 0 to 8 m (4.56 m ± 2.12 m). The other nine sheep (19%) performed a ‘generalised fear response’, where they ran as soon as the start box was opened and before viewing the observer.
4. Discussion As hypothesized, pen design affected the group flight distance of focal sheep. As we used the same focal sheep, flight distance should have been unchanged if pens were not an influence. However, group flight distances were greater in large pens and smaller in small pens. In alignment with our study, Hutson (1982) also found that flight distances of Merino sheep flocks were greater in wider laneways and smaller in narrow laneways. Our results indicate that this relationship between group flight distance and pen size is linear, as the group flight distance and maximum dimension of each pen increased in a linear way. This suggests that pen shape may be negligible, as was found in a study where pens altered by shape (width and depth) but consistent in area had no effect on the displacement behaviour of ewes (Bøe et al., 2006). We can conclude that pen size is a major determinant of group flight distance that may confound results, and that the shape of test pens warrants further research. The raw results from the group flight distance tests were effectively linear, so our results do not give a clear indication of what the natural flight distances of the study sheep were, as there was no plateau of flight distance. Extensively managed sheep have been known to exhibit flight distances of up to 38 m, which means the natural flight zones of focal sheep may have exceeded the size of all pens (Grandin and Shivley, 2015; Turner and Dwyer, 2007). It is possible that these natural flight zones were constrained in all pens but were further restricted in those that were smaller, leading to smaller flight distances. This rationale, based on the observed linear trend in the present study, supports the hypothesis that small enclosures constrict the size of an animal’s
3.2. Group flight distance test 3.2.1. Raw group flight distance Based on the same 48 animals tested daily for four days, the raw group flight distance ranged from 1.1 m to 14.8 m (M ± SD = 4.67 m ± 3.18 m). Raw group flight distance was significantly affected by pen design (P < 0.001), being greater in large pens and smaller in small pens, however we cannot conclude that pen shape was independently influential. Flight distances were 2.62 m ± 0.77 m in SR, 2.20 m ± 0.66 m in MR, 9.51 m ± 2.12 m in LR and 4.46 m ± 1.23 m in C (Fig. 3). Post-hoc pairwise comparisons further revealed that these results were significantly different (P < 0.05) between all four pen designs. Flight distance also ranged within pens, indicating that results were different across days, groups and/or animals within groups. 3.2.2. Adjusted group flight distance The adjusted group flight distance ranged from 0.15 to 0.66 (M = 0.36 ± 0.11). Adjusted group flight distance was significantly affected by a Day x Pen interaction (F9,84 = 3.01, P < 0.004); however, post-hoc pairwise comparisons showed no clear pattern across pens or days (Fig. 4). There was no detection of intra-observer drift on adjusted group flight distance and no evidence to suggest that focal sheep habituated or became sensitised to the repeated testing. 4
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Fig. 4. Bar graph with individual data points comparing the Least Square Means of the adjusted group flight distance between pens and across days. Error bars represent Standard Error of the Least Square Means and labels with different numbers are significantly different (P < 0.05). Analysing group flight distance as a proportion of the pen improved the comparability of data between pens, as the Day x Pen interaction showed no clear pattern on adjusted group flight distance across days or pens.
flight zone (Hutson and Grandin, 2014). These findings support the theory that the influence of pen design on HAR indicators, including flight distance tests, may mislead our interpretations of the measures (de Passillé and Rushen, 2005; Napolitano et al., 2011). Natural flight zones, and the effect of restricting these zones, need to be further investigated if group flight distance tests are to be validated in pens and used in welfare assessments. Differences in pen design must be eliminated or accounted for in order to mitigate their confounding effect on group flight distance. The influence of pen design can be removed by conducting the test in identical pens, but this is not a feasible on-farm solution because sheep yards are heterogeneous and inherently differ between and within farms. Instead, we hypothesised that the pen effects were determined by the maximum possible flight distance that could be performed in each pen. Based on this premise, a mathematical approach that analysed group flight distance as a proportion of the maximum dimension in each pen was applied to the data. The effects of pen design were negated and the comparability of the results between pens markedly improved. By accounting for the effects of pen design using the simple mathematical adjustment, we can place more confidence in our interpretations of the HAR using group flight distance. This is an important consideration if flight distance and human-sheep relationships are to be compared between pens, farms, and other studies. Whilst the present study attempted to deal with the uncontrolled factor of pen design in the AWIN (2015) protocol, there are a number of other variables requiring consideration before the group flight distance test can be validated for welfare assessments. Method of approach, flock size and criteria for determining flight distance were other inconsistent
aspects of the protocol that were addressed and standardised in the adapted methodology used in the current study. Environmental noise is another uncontrolled factor in the on-farm group flight distance test which may differ between and within test locations. Noise has been previously shown to affect the physiological and physical parameters measured in sheep (Grandin, 1980; Hall et al., 2010). Although our results indicated no significant influence of decibels on adjusted group flight distance, it was not possible to analyse full interactions, so a larger sample size is required. Uncontrolled variables are an inevitable aspect of on-farm tests, but by investigating the effects and developing strategies to alleviate them, it will allow group flight distance results to be compared between farms. Failure to correlate the group and isolated flight distances could be attributed to differences in the social environments. Conspecifics are integral for forming sheep defensive behaviours, such as flocking (Dwyer, 2009). Consequently, social isolation can inflict a significant amount of stress on sheep, particularly those normally managed in groups (Waiblinger et al., 2006). The social seclusion experienced in the isolated flight distance test may have caused focal sheep to react in a way that differed to their response within the group setting. This could have occurred during the settling period which was termed a ‘social distress period’ by Boivin et al. (2003). In the current study, the direction and magnitude of this social separation effect was not clear, except Hutson (1982) found individual flight distances of Merino sheep were larger than flock flight distances. Isolated flight distances cannot be extrapolated to reflect the fear of extensively managed sheep flocks but may be more suitable when assessing individual sheep fear during procedures such as crutching and shearing. 5
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animals.
The ewes in our study responded in two different ways during the isolated flight distance test, with 19% of animals eliciting a ‘generalised fear response’ and the remaining performing a flight response. The ‘generalised fear response’ was not an outcome of the group flight distance test, nor was it reported in the original test by Hargreaves and Hutson (1990). However, two distinct reactions to human presence have been described for sheep, where active responses featured locomotion and vocalisations, whilst passive responses involved freezing and vigilance (Vandenheede et al., 1998). These two categories could potentially translate to our results, with the ‘generalised fear response’ resembling an active reaction and the flight response being a passive reaction. Alternatively, Boissy et al. (2005) found that sheep perform two similar fear reactions in response to social isolation during arena and corridor tests. This finding infers that the ‘generalised fear response’ was potentially an active reaction to social isolation. It is possible that ‘generalised fear response’ sheep were reacting to restriction in the start box, causing an immediate stress response unrelated to fear of human approach. A similar trend was seen in an arena test with an immobile human, where ‘More Active’ lambs showed more locomotion but were less fearful than ‘Less Active’ lambs (Beausoleil et al., 2008). Given the habituation time was 30 s in the start box as opposed to 10 min in the pen, the isolated flight distance of all sheep may have been confounded by stress induced from the procedure and environment. The isolated flight distance test may be sufficient for assessing housed sheep that are habituated to procedures similar to the test protocol, but not for testing extensively managed sheep (Richmond et al., 2017).
References AWIN, 2015. AWIN Welfare Assessment Protocol for Sheep. Available:. https://doi.org/ 10.13130/AWIN_SHEEP_2015. Beausoleil, N.J., Blache, D., Stafford, K.J., Mellor, D.J., Noble, A.D.L., 2008. Exploring the basis of divergent selection for ‘temperament’ in domestic sheep. Appl. Anim. Behav. Sci. 109, 261–274. Bøe, K.E., Berg, S., Andersen, I.L., 2006. Resting behaviour and displacements in ewes—effects of reduced lying space and pen shape. Appl. Anim. Behav. Sci. 98, 249–259. Boissy, A., Bouix, J., Orgeur, P., Poindron, P., Bibé, B., Le Neindre, P., 2005. Genetic analysis of emotional reactivity in sheep: effects of the genotypes of the lambs and of their dams. Genet. Sel. Evol. 37, 381–401. Boivin, X., Lensink, J., Tallet, C., Veissier, I., 2003. Stockmanship and farm animal welfare. Anim. Welf. 12, 479–492. Cohen, J., 2013. The significance of a product moment Rs. In: Cohen, J. (Ed.), Statistical Power Analysis for the Behavioral Sciences. Taylor & Francis, London. De Passillé, A.M., Rushen, J., 2005. Can we measure human–animal interactions in onfarm animal welfare assessment?: some unresolved issues. Appl. Anim. Behav. Sci. 92, 193–209. Dwyer, C.M., 2009. Welfare of sheep: providing for welfare in an extensive environment. Small Rumin. Res. 86, 14–21. Grandin, T., 1980. The effect of stress on livestock and meat quality prior to and during slaughter. Int. J. Study Anim. Probl. 1, 313–337. Grandin, T., 2008. Principles for handling grazing animals. In: Benson, G.J., Rollin, B.E. (Eds.), The Well-Being of Farm Animals: Challenges and Solutions. Wiley, Iowa. Grandin, T., Deesing, M.J., 2014. Genetics and behavior during handling, restraint, and herding. In: Grandin, T., Deesing, M.J. (Eds.), Genetics and the Behavior of Domestic Animals, Second edition. Academic Press, San Diego. Grandin, T., Shivley, C., 2015. How farm animals react and perceive stressful situations such As handling, restraint, and transport. Animals 5, 1233–1251. Hall, S.J.G., Kirkpatrick, S.M., Lloyd, D.M., Broom, D.M., 2010. Noise and vehicular motion as potential stressors during the transport of sheep. Anim. Sci. 67, 467–473. Hargreaves, A.L., Hutson, G.D., 1990. The effect of gentling on heart rate, flight distance and aversion of sheep to a handling procedure. Appl. Anim. Behav. Sci. 26, 243–252. Hemsworth, P.H., Coleman, G.J., 2011. A model of stockperson-animal interactions and their implications for livestock. In: Hemsworth, P.H., Coleman, G.J. (Eds.), HumanLivestock Interactions: The Stockperson and the Productivity and Welfare of Intensively Farmed Animals. CABI, Wallingford, UK. Hutson, G.D., 1982. ‘Flight distance’ in Merino sheep. Anim. Prod. Sci. 35, 231–235. Hutson, G.D., Grandin, T., 2014. Behavioural principles of sheep handling. In: Hutson, G.D., Grandin, T. (Eds.), Livestock Handling and Transport, 4th Edition: Theories and Applications. CABI, Wallingford, UK. Munoz, C.M., Campbell, A., Barber, S., Hemsworth, P.H., Doyle, R.E., 2018. Using longitudinal assessment on extensively managed ewes to quantify welfare compromise and risks. Animals 8, 8. Napolitano, F., De Rosa, G., Girolami, A., Scavone, M., Braghieri, A., 2011. Avoidance distance in sheep: test–retest reliability and relationship with stockmen attitude. Small Rumin. Res. 99, 81–86. Richmond, S.E., Wemelsfelder, F., De Heredia, I.B., Ruiz, R., Canali, E., Dwyer, C.M., 2017. Evaluation of Animal-Based Indicators to Be Used in a Welfare Assessment Protocol for Sheep. Front. Vet. Sci. 4, 210. Rstudio Team, 2018. RStudio: Integrated Development for R. R Version 3.6.0 (2019-0426) – "Planting of a Tree" Ed. RStudio, Inc., Boston, MA. Skypaw Co Ltd, 2017. Decibel 10. 5.4.1 Ed. Turner, S., Dwyer, C.M., 2007. Welfare assessment in extensive animal production systems: challenges and opportunities. Anim. Welf. 16, 189–192. Vandenheede, M., Bouissou, M.F., Picard, M., 1998. Interpretation of behavioural reactions of sheep towards fear-eliciting situations. Appl. Anim. Behav. Sci. 58, 293–310. Waiblinger, S., Boivin, X., Pedersen, V., Tosi, M.-V., Janczak, A.M., Visser, E.K., Jones, R.B., 2006. Assessing the human–animal relationship in farmed species: a critical review. Appl. Anim. Behav. Sci. 101, 185–242.
5. Conclusion Group flight distance tests can be a useful on-farm tool for measuring the human-animal relationship in extensively managed sheep, but results are influenced by pen size, and possibly pen shape. To account for differences in pen design, we proposed a simple mathematical approach that mitigated pen effects. Implementation of this method could allow group flight distance comparisons to be made between pens, sites and studies. Variations between the isolated and group flight distance test protocols were not as easily adjusted or accounted for. This suggests that isolated flight distances cannot be extrapolated to group flight distance and highlights the need for situation-specific tests. Declaration of Competing Interest None Acknowledgements This project was funded by the Faculty of Veterinary and Agricultural Sciences, the University of Melbourne. Thanks are due to Kym Butler and Ellen Jongman for providing study design input, and the farm staff of Dookie College for the care and provision of the
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Contents lists available at ScienceDirect
Applied Animal Behaviour Science journal homepage: www.elsevier.com/locate/applanim
Investigating the effect of pen shape and pen size on group flight distance of extensively managed ewes Samantha R. Cramera, Carolina A. Munoza, David M. McGillb, Maxine Ricea, Rebecca E. Doylea,* a b
Animal Welfare Science Centre, Level 2, 21 Bedford St, University of Melbourne, North Melbourne, 3051 VIC, Australia Faculty of Veterinary and Agricultural Sciences, 250 Princes Highway, The University of Melbourne, Werribee, 3030 VIC, Australia
A R T I C LE I N FO
A B S T R A C T
Keywords: Animal welfare assessment Animal-based indicator Fear Flight zone Human-animal relationship
This study investigated the effect of pen shape and pen size on the group flight distance of extensively managed ewes, and how flight distances of individual ewes compared when recorded in group and isolated settings. Within eight groups of 25 sheep, six focal animals were randomly selected (N = 48 ewes). Over four days, groups were placed in four different sized and shaped pens and flight distances (m) of focal animals were recorded. Pens designs were small rectangle (3.3 m x 7.2 m), medium rectangle (4.8 m x 5.8 m), large rectangle (11 m x 19.6 m) and curved/concave (with 31.5 m perimeter). Following a previously validated protocol, flight distance (m) was also recorded when focal sheep were physically isolated from conspecifics. There was no association between the isolated flight distance and group flight distance of focal animals (n = 39, r(37) = 0.03, P = 0.83). Group flight distance was significantly affected by pen design (P < 0.001), being greater in large pens and smaller in small pens. To account for these pen effects, group flight distance was adjusted and analysed as a proportion of the largest dimension of each pen. To test this mathematical adjustment, pen and other variables predicted to have an influence on adjusted group flight distance were analysed as fixed effects in linear mixed models. A statistically significant Day x Pen interaction was found (F9,84 = 3.01, P < 0.004), although post-hoc pairwise comparisons showed that this interaction had no clear pattern across days or pens. The simple mathematical adjustment and statistical modelling made group flight distances comparable by accounting for day and pen effects. These results suggest that analysing group flight distance as a proportion of the pen in future welfare assessments will enable comparisons to be made between sites.
1. Introduction The human-animal relationship (HAR) represents the direct impact farmer or stockperson (terms used interchangeably here) attitudes and behaviours have on animal fear, stress, welfare and productivity (Hemsworth and Coleman, 2011). The HAR of extensively managed sheep involves neutral or aversive stockperson handling on an infrequent basis (Dwyer, 2009). This gives animals little opportunity to habituate to human contacts leading to stress and fear when they do occur (Turner and Dwyer, 2007). Human-sheep relationship indicators are required to assess how variations between farmer handling and positive behaviours may result in less fear and stress and a calmer behavioural response (Hemsworth and Coleman, 2011). Flight distance tests that ascertain the level of fear and stress experienced by sheep in response to an approaching human (Grandin and
Deesing, 2014) can be used as HAR indicators in welfare assessments. Hargreaves and Hutson (1990) conducted an individual flight distance test where ewes were isolated from conspecifics, placed in a start box and released into a race as a human approached from the opposite end. This validated test is practical for on-farm welfare assessments because it relies on single race infrastructure that is relatively consistent across farms, allowing for between site comparisons. However, as sheep are a highly social species, individual tests are assumed to have little relevance when assessing extensively managed sheep because the fear experienced by single sheep may not reflect fear of the flock, and the stress of social isolation may confound results (Boivin et al., 2003; Waiblinger et al., 2006). For these reasons, group flight distance tests may be more suitable when assessing extensively managed sheep as social isolation is nullified. Group flight distance may be determined by measuring the flight
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Corresponding author at: Animal Welfare Science Centre, Faculty of Veterinary and Agricultural Sciences, Level 2, 21 Bedford St, The University of Melbourne, North Melbourne, Victoria 3051, Australia. E-mail addresses: [email protected] (S.R. Cramer), [email protected] (C.A. Munoz), [email protected] (D.M. McGill), [email protected] (M. Rice), [email protected] (R.E. Doyle). https://doi.org/10.1016/j.applanim.2019.104887 Received 13 December 2018; Received in revised form 13 October 2019; Accepted 23 October 2019 0168-1591/ Crown Copyright © 2019 Published by Elsevier B.V. All rights reserved.
Please cite this article as: Samantha R. Cramer, et al., Applied Animal Behaviour Science, https://doi.org/10.1016/j.applanim.2019.104887
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Fig. 1. Isolated flight distance test: sheep were physically isolated from conspecifics and released from the start box and traversed the race before entering the post-test pen. Following the sheep’s exit from the start box, the observer approached from the start point until a flight response was observed and the flight distance (m) was recorded. This test was repeated on all 48 focal sheep.
inter-observer variation. Ewes were kept in four paddocks in between tests. In order to do this, the same two groups were combined overnight and then redrafted into their groups of 25 each day before testing.
distance of an individual ewe when within a group setting (Napolitano et al., 2011) or by recording the flight distance at the flock level, as has been proposed in the AWIN (2015) welfare assessment protocol for sheep. This protocol presents a practical option for assessing the human-sheep relationship, but there is no formal definition or criteria to determine group flight distance. Furthermore, there is no published evidence of this test being standardised for uncontrolled variables that inherently exist between farms, such as pen design, testing locations, method of approach, flock size and noise. The impact of different enclosures may confound results, as work by Napolitano et al. (2011) indicated that pen design and space allowances of testing facilities were likely to play a role in the expression of fear and flight distance. Additionally, sheep managed in extensive settings, including Australian farming systems, naturally display large flight zones (Grandin, 2008). This makes understanding the effect of pen design on group flight distance even more important because the impact of flight zones that exceed testing locations is unknown. We hypothesised that differences in pen design confound group flight distance test results used in welfare assessments. The present study aimed to investigate the effect of pen shape and pen size on the group flight distance of extensively managed ewes, using a standardised group flight distance test adapted from the Napolitano et al. (2011) and AWIN (2015) protocols. Mathematical adjustments to account for the pen differences were also tested. The Hargreaves and Hutson (1990) individual flight distance test was included to examine how flight distances of individual ewes compared when recorded in group and isolated settings.
2.2.1. Isolated flight distance test This test was used to assess the flight distance of focal sheep when physically isolated from conspecifics, and was adapted from the previously validated individual flight distance test by Hargreaves and Hutson (1990). Behavioural responses to an approaching human were tested using a start box and a race located in the sheep yards. The portable start box was a standard weighing crate with enclosed wooden walls (1.27 m x 0.52 m x 0.81 m) that was placed and opened to the front of the race (18.5 m x 1.1 m) (Fig.1). Markers were placed at 2 m increments along the race. Three GoPro HERO4 Silver edition cameras (GoPro, Inc., San Mateo, California, U.S.) continuously recorded the start box and race during the test. Test focal animals were visually isolated from conspecifics during the test, but audible range was maintained. All tests were conducted over one day. For this test, the six focal animals from each of the eight groups (N = 48) were drafted and tested once individually. Ewes were given 10 min to settle in the pre-test pen before behavioural testing commenced. Test sheep were individually caught by a handler and placed in the start box facing the doors. The ewe was given 30 s to settle before the start box doors were released. When the ewe exited the start box, the observer approached the ewe from the opposite end at the start point (Fig.1), at a pace of 1 step/s while facing the start box. The observer looked towards the ewe and approached with arms against the torso. The observer stopped approaching when a flight response was observed, which was defined as the point at which the ewe began to run past the observer (Hargreaves and Hutson, 1990). The isolated flight distance (m) was recorded as the distance between the observer’s feet and the ewe’s front hooves at the time of flight response. The markers were used as a guide to estimate the isolated flight distance and this was obtained post-hoc from the GoPro footage. The test period was over when the ewe entered the post-race pen.
2. Materials and methods This project received approval from the University of Melbourne Faculty of Veterinary and Agricultural Sciences Animal Ethics Committee (Ethics ID 1714127). 2.1. Animals & husbandry Two hundred single-bearing Merino ewes (aged 2–4 years) in early pregnancy (1–2 months gestation) were randomly selected for this study from a large flock of 3000 breeding ewes. The flock was raised extensively in a year-round outdoor system and managed in paddocks with limited human contacts. For the duration of the study, the 200 ewes were housed in paddocks in accordance with the University of Melbourne’s farm management protocol. The paddocks were in close proximity to the sheep yards and testing locations to limit daily handling.
2.2.2. Group flight distance test This test was used to assess the flight distance of focal sheep in a group situation using methodology by Munoz et al. (2018) which was adapted from existing group flight distance tests by Napolitano et al. (2011) and the AWIN (2015) welfare assessment protocol for sheep. Flight distance to an approaching human were tested using four constructed pens within the sheep yards. The dimensions were adapted from the most common pen designs that were observed across 32 Victorian farms during the larger project that applied the same group flight distance test (Munoz et al., 2018). The small rectangle (SR) measured 3.3 m x 7.2 m, the medium rectangle (MR) measured 4.8 m x 5.8 m, the large rectangle (LR) measured 11 m x 19.6 m and the curved/concave (C) measured a perimeter of 31.5 m (Fig. 2). Test groups were visually isolated from other groups during the test, but audible range was maintained. Tests were conducted over four days with each group being tested in one pen per day. All eight groups were tested in each of the four pens using a cross-over design, to ensure that the repeated measures were balanced for all pen designs. Flight distance was recorded for the six focal animals within each group (N = 192).
2.2. Experimental design, procedure and behaviour assessments Ewes were randomly divided into eight groups of 25 animals, identified with washable spray marker sprayed onto backs, and remained in these same groups for the duration of the experiment. Within each group of 25 ewes, six focal animals were randomly selected and individually identified with washable spray marker sprayed onto backs, and they remained as focal animals for all behavioural testing. The same researcher (SRC) conducted all flight distance tests to eliminate 2
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Fig. 2. Group flight distance test: groups of sheep were allocated to constructed pens of different shape and size. The observer started at the start point and approached a focal animal until a flight response was observed and the flight distance (m) was recorded. This process was repeated for all six focal animals within each group.
distance was also analysed as a proportion of the pen, as opposed to an absolute value. To adjust for these differences, the maximum dimension of each pen (diagonal; exact or estimated) was obtained and used to calculate the group flight distance as a proportion of the dimension length. The diagonal was the largest flight distance a sheep could establish between itself and the observer, positioned at the start point. The diagonal dimension was calculated exactly as 7.9 m for SR, 7.5 m for MR, 22.5 m for LR and estimated as 11.1 m for C. Results are reported as Mean ± Standard Deviation. Variables that were predicted to have an influence on adjusted group flight distance were analysed as fixed effects in linear mixed models and tested for statistical significance during preliminary analyses. Variables that had no statistically significant effect were removed from the final linear mixed model. Pen was included to investigate the effect of pen design. To investigate the effect of environmental noise, decibels (minimum, average and maximum) were included, however all three variables overfit linear mixed models when analysed as interactions and were subsequently removed from the final analyses. To detect intra-observer bias/drift and habituation or sensitisation of focal sheep, we considered variables (of varying complexity) that examined change in the adjusted group flight distances over time. These variables were day, time interval (AM or PM), the order of focal sheep tests within their respective group test (N = 6), the total order of focal sheep tests (N = 192), the order of group tests within days (N = 8) and the total order of group tests (N = 32). The total order of focal sheep tests, the order of group tests within days and the total order of group tests overfit the linear mixed models and were subsequently removed from the final analyses. The final linear mixed model, used for all subsequent analyses, incorporated pen and day as fixed factors. Focal sheep nested within group was incorporated as a random effect but was found to overfit the linear mixed model. Instead, group was analysed as a random effect to account for variations between groups. 2.3.2.2.1. Final linear mixed model. Adjusted group flight distance = Pen x Day + Group Post-hoc pairwise comparisons for pen and day were conducted using Least Square Means Differences and the Tukey method for p-value adjustment. Results are reported as Least Square Means ± Standard Error of the Least Square Means.
The group was moved to the pen and given 10 min to settle before the test started. The observer then entered the pen at the start point (Fig. 2) and walked anticlockwise around the perimeter at a rate of 1 step/s, with arms beside the torso and gaze held at eye level. After the observer returned to the start point, the observer waited for the group to settle, which was defined as the point at which the whole group exhibited no mobile movement or displacements for at least 3 s. The observer randomly selected one of the six marked focal animals and approached the ewe at a pace of 1 step/s. The observer looked towards the ewe and approached with arms against the torso. The observer stopped approaching when a flight response was observed, which was defined as the point at which the ewe stepped away/withdrew in an attempt to re-establish the flight zone. A surveyor wheel was used to measure the group flight distance, and this was obtained immediately after the flight response. The group flight distance (m) was recorded as the distance between the observer’s feet and the middle of the ewe’s back at the time of flight response. The observer then returned to the start point and the same process was performed on the remaining focal animals in the group. As noise was an uncontrolled factor, the environmental noise within the sheep yards was recorded during the tests by measuring decibel minimums, averages and maximums using the mobile phone application Decibel 10 for iOS version 5.3.3 (Skypaw Co Ltd, 2017). 2.3. Statistical analysis All statistical analyses were conducted using R Version 3.6.0 (RStudio Team, 2018). A statistical significance value of P < 0.05 was used for all statistical analyses. A stepwise approach using graphical representations was employed to inform decisions when assessing the normality of the data distributions, and residuals of outputs. Bartlett’s test was conducted to assess the homogeneity of variances. 2.3.1. Isolated flight distance test During the test, it was clear that the reactions of sheep varied after release from the start box. The reaction type was binary, with some sheep displaying a flight response after viewing the observer and others starting flight as soon as the start box opened and before viewing the observer. Sheep that performed the latter response have been categorised as having a ‘generalised fear response’. Results are presented as Mean ± Standard Deviation.
2.3.3. Isolated and group flight distance test comparisons ‘Generalised fear response’ sheep were excluded from this analysis. To investigate the relationship between focal animal behaviour within the isolated and group flight distance test, a Pearson’s correlation test was performed between each focal animals’ isolated flight distance and average adjusted group flight distance. Correlation coefficients of 0.30.49 were deemed moderate, and coefficients from 0.50 were deemed strong (Cohen, 2013).
2.3.2. Group flight distance test 2.3.2.1. Raw group flight distance. To investigate the effect of pen design on group flight distance, raw data was analysed using a linear model with unequal variances. Post-hoc pairwise comparisons were conducted using a Fisher Least Significant Differences test. Results are presented as Mean ± Standard Deviation. 2.3.2.2. Adjusted group flight distance. To account for differences in flight distance that were influenced by pen shape and size, group flight 3
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Fig. 3. Boxplot with individual data points comparing the distribution of raw group flight distance measures between and within pens. Raw group flight distance was significantly different (P < 0.05) between all four pen designs.
3. Results
3.3. Isolated and group flight distance test comparisons
3.1. Isolated flight distance test
There was no association between the isolated and average adjusted group flight distances of focal animals (n = 39, r(37) = 0.03, P = 0.83).
A total of 39 sheep showed a flight response after viewing the observer with flight distances ranging from 0 to 8 m (4.56 m ± 2.12 m). The other nine sheep (19%) performed a ‘generalised fear response’, where they ran as soon as the start box was opened and before viewing the observer.
4. Discussion As hypothesized, pen design affected the group flight distance of focal sheep. As we used the same focal sheep, flight distance should have been unchanged if pens were not an influence. However, group flight distances were greater in large pens and smaller in small pens. In alignment with our study, Hutson (1982) also found that flight distances of Merino sheep flocks were greater in wider laneways and smaller in narrow laneways. Our results indicate that this relationship between group flight distance and pen size is linear, as the group flight distance and maximum dimension of each pen increased in a linear way. This suggests that pen shape may be negligible, as was found in a study where pens altered by shape (width and depth) but consistent in area had no effect on the displacement behaviour of ewes (Bøe et al., 2006). We can conclude that pen size is a major determinant of group flight distance that may confound results, and that the shape of test pens warrants further research. The raw results from the group flight distance tests were effectively linear, so our results do not give a clear indication of what the natural flight distances of the study sheep were, as there was no plateau of flight distance. Extensively managed sheep have been known to exhibit flight distances of up to 38 m, which means the natural flight zones of focal sheep may have exceeded the size of all pens (Grandin and Shivley, 2015; Turner and Dwyer, 2007). It is possible that these natural flight zones were constrained in all pens but were further restricted in those that were smaller, leading to smaller flight distances. This rationale, based on the observed linear trend in the present study, supports the hypothesis that small enclosures constrict the size of an animal’s
3.2. Group flight distance test 3.2.1. Raw group flight distance Based on the same 48 animals tested daily for four days, the raw group flight distance ranged from 1.1 m to 14.8 m (M ± SD = 4.67 m ± 3.18 m). Raw group flight distance was significantly affected by pen design (P < 0.001), being greater in large pens and smaller in small pens, however we cannot conclude that pen shape was independently influential. Flight distances were 2.62 m ± 0.77 m in SR, 2.20 m ± 0.66 m in MR, 9.51 m ± 2.12 m in LR and 4.46 m ± 1.23 m in C (Fig. 3). Post-hoc pairwise comparisons further revealed that these results were significantly different (P < 0.05) between all four pen designs. Flight distance also ranged within pens, indicating that results were different across days, groups and/or animals within groups. 3.2.2. Adjusted group flight distance The adjusted group flight distance ranged from 0.15 to 0.66 (M = 0.36 ± 0.11). Adjusted group flight distance was significantly affected by a Day x Pen interaction (F9,84 = 3.01, P < 0.004); however, post-hoc pairwise comparisons showed no clear pattern across pens or days (Fig. 4). There was no detection of intra-observer drift on adjusted group flight distance and no evidence to suggest that focal sheep habituated or became sensitised to the repeated testing. 4
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Fig. 4. Bar graph with individual data points comparing the Least Square Means of the adjusted group flight distance between pens and across days. Error bars represent Standard Error of the Least Square Means and labels with different numbers are significantly different (P < 0.05). Analysing group flight distance as a proportion of the pen improved the comparability of data between pens, as the Day x Pen interaction showed no clear pattern on adjusted group flight distance across days or pens.
flight zone (Hutson and Grandin, 2014). These findings support the theory that the influence of pen design on HAR indicators, including flight distance tests, may mislead our interpretations of the measures (de Passillé and Rushen, 2005; Napolitano et al., 2011). Natural flight zones, and the effect of restricting these zones, need to be further investigated if group flight distance tests are to be validated in pens and used in welfare assessments. Differences in pen design must be eliminated or accounted for in order to mitigate their confounding effect on group flight distance. The influence of pen design can be removed by conducting the test in identical pens, but this is not a feasible on-farm solution because sheep yards are heterogeneous and inherently differ between and within farms. Instead, we hypothesised that the pen effects were determined by the maximum possible flight distance that could be performed in each pen. Based on this premise, a mathematical approach that analysed group flight distance as a proportion of the maximum dimension in each pen was applied to the data. The effects of pen design were negated and the comparability of the results between pens markedly improved. By accounting for the effects of pen design using the simple mathematical adjustment, we can place more confidence in our interpretations of the HAR using group flight distance. This is an important consideration if flight distance and human-sheep relationships are to be compared between pens, farms, and other studies. Whilst the present study attempted to deal with the uncontrolled factor of pen design in the AWIN (2015) protocol, there are a number of other variables requiring consideration before the group flight distance test can be validated for welfare assessments. Method of approach, flock size and criteria for determining flight distance were other inconsistent
aspects of the protocol that were addressed and standardised in the adapted methodology used in the current study. Environmental noise is another uncontrolled factor in the on-farm group flight distance test which may differ between and within test locations. Noise has been previously shown to affect the physiological and physical parameters measured in sheep (Grandin, 1980; Hall et al., 2010). Although our results indicated no significant influence of decibels on adjusted group flight distance, it was not possible to analyse full interactions, so a larger sample size is required. Uncontrolled variables are an inevitable aspect of on-farm tests, but by investigating the effects and developing strategies to alleviate them, it will allow group flight distance results to be compared between farms. Failure to correlate the group and isolated flight distances could be attributed to differences in the social environments. Conspecifics are integral for forming sheep defensive behaviours, such as flocking (Dwyer, 2009). Consequently, social isolation can inflict a significant amount of stress on sheep, particularly those normally managed in groups (Waiblinger et al., 2006). The social seclusion experienced in the isolated flight distance test may have caused focal sheep to react in a way that differed to their response within the group setting. This could have occurred during the settling period which was termed a ‘social distress period’ by Boivin et al. (2003). In the current study, the direction and magnitude of this social separation effect was not clear, except Hutson (1982) found individual flight distances of Merino sheep were larger than flock flight distances. Isolated flight distances cannot be extrapolated to reflect the fear of extensively managed sheep flocks but may be more suitable when assessing individual sheep fear during procedures such as crutching and shearing. 5
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animals.
The ewes in our study responded in two different ways during the isolated flight distance test, with 19% of animals eliciting a ‘generalised fear response’ and the remaining performing a flight response. The ‘generalised fear response’ was not an outcome of the group flight distance test, nor was it reported in the original test by Hargreaves and Hutson (1990). However, two distinct reactions to human presence have been described for sheep, where active responses featured locomotion and vocalisations, whilst passive responses involved freezing and vigilance (Vandenheede et al., 1998). These two categories could potentially translate to our results, with the ‘generalised fear response’ resembling an active reaction and the flight response being a passive reaction. Alternatively, Boissy et al. (2005) found that sheep perform two similar fear reactions in response to social isolation during arena and corridor tests. This finding infers that the ‘generalised fear response’ was potentially an active reaction to social isolation. It is possible that ‘generalised fear response’ sheep were reacting to restriction in the start box, causing an immediate stress response unrelated to fear of human approach. A similar trend was seen in an arena test with an immobile human, where ‘More Active’ lambs showed more locomotion but were less fearful than ‘Less Active’ lambs (Beausoleil et al., 2008). Given the habituation time was 30 s in the start box as opposed to 10 min in the pen, the isolated flight distance of all sheep may have been confounded by stress induced from the procedure and environment. The isolated flight distance test may be sufficient for assessing housed sheep that are habituated to procedures similar to the test protocol, but not for testing extensively managed sheep (Richmond et al., 2017).
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5. Conclusion Group flight distance tests can be a useful on-farm tool for measuring the human-animal relationship in extensively managed sheep, but results are influenced by pen size, and possibly pen shape. To account for differences in pen design, we proposed a simple mathematical approach that mitigated pen effects. Implementation of this method could allow group flight distance comparisons to be made between pens, sites and studies. Variations between the isolated and group flight distance test protocols were not as easily adjusted or accounted for. This suggests that isolated flight distances cannot be extrapolated to group flight distance and highlights the need for situation-specific tests. Declaration of Competing Interest None Acknowledgements This project was funded by the Faculty of Veterinary and Agricultural Sciences, the University of Melbourne. Thanks are due to Kym Butler and Ellen Jongman for providing study design input, and the farm staff of Dookie College for the care and provision of the
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