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Author Wathan, J.; Burrows, A.M.; Waller, B.M.; McComb, K. url  doi
openurl 
  Title EquiFACS: The Equine Facial Action Coding System Type Journal Article
  Year 2015 Publication PLoS ONE Abbreviated Journal PLoS ONE  
  Volume 10 Issue 8 Pages e0131738  
  Keywords  
  Abstract <p>Although previous studies of horses have investigated their facial expressions in specific contexts, e.g. pain, until now there has been no methodology available that documents all the possible facial movements of the horse and provides a way to record all potential facial configurations. This is essential for an objective description of horse facial expressions across a range of contexts that reflect different emotional states. Facial Action Coding Systems (FACS) provide a systematic methodology of identifying and coding facial expressions on the basis of underlying facial musculature and muscle movement. FACS are anatomically based and document all possible facial movements rather than a configuration of movements associated with a particular situation. Consequently, FACS can be applied as a tool for a wide range of research questions. We developed FACS for the domestic horse (<italic>Equus caballus</italic>) through anatomical investigation of the underlying musculature and subsequent analysis of naturally occurring behaviour captured on high quality video. Discrete facial movements were identified and described in terms of the underlying muscle contractions, in correspondence with previous FACS systems. The reliability of others to be able to learn this system (EquiFACS) and consistently code behavioural sequences was high?and this included people with no previous experience of horses. A wide range of facial movements were identified, including many that are also seen in primates and other domestic animals (dogs and cats). EquiFACS provides a method that can now be used to document the facial movements associated with different social contexts and thus to address questions relevant to understanding social cognition and comparative psychology, as well as informing current veterinary and animal welfare practices.</p>  
  Address  
  Corporate Author Thesis  
  Publisher Public Library of Science Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN (up) Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5973  
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Author Krueger, K.; Schneider, G.; Flauger, B.; Heinze, J. doi  openurl
  Title Context-dependent third-party intervention in agonistic encounters of male Przewalski horses Type Journal Article
  Year 2015 Publication Behavioural Processes Abbreviated Journal Behav. Process.  
  Volume 121 Issue Pages 54-62  
  Keywords Equus ferus przewalskii; Group conflict; Rank orders; Social bonds; Social control; Third-party intervention  
  Abstract Abstract One mechanism to resolve conflict among group members is third party intervention, for which several functions, such as kin protection, alliance formation, and the promotion of group cohesion have been proposed. Still, empirical research on the function of intervention behaviour is rare. We studied 40 cases of intervention behaviour in a field study on 13 semi-wild bachelor horses (Equus ferus przewalskii) in (a) standard social situations, and (b) when new horses joined the group (i.e. introductions). Only interventions in agonistic encounters were analysed. Eight of 13 animals directed intervention behaviour toward threatening animal in agonistic encounters of group members. One stallion was particularly active. The stallions did not intervene to support former group mates or kin and interventions were not reciprocated. In introduction situations and in standard social situations, the interveners supported animals which were lower in rank, but targeted, threatening animals of comparable social rank. After introductions, stallions received more affiliative behaviour from animals they supported and thus appeared to intervene for alliance formation. In standard social situations, interveners did not receive more affiliative behaviour from animals they supported and may primarily have intervened to promote group cohesion and to reduce social disruption within the group.  
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  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0376-6357 ISBN (up) Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5925  
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Author Huebner, F.; Fichtel, C. url  doi
openurl 
  Title Innovation and behavioral flexibility in wild redfronted lemurs (Eulemur rufifrons) Type Journal Article
  Year 2015 Publication Animal Cognition Abbreviated Journal Anim.Cogn.  
  Volume 18 Issue 3 Pages 777-787  
  Keywords  
  Abstract Innovations and problem-solving abilities can provide animals with important ecological advantages as they allow individuals to deal with novel social and ecological challenges. Innovation is a solution to a novel problem or a novel solution to an old problem, with the latter being especially difficult. Finding a new solution to an old problem requires individuals to inhibit previously applied solutions to invent new strategies and to behave flexibly. We examined the role of experience on cognitive flexibility to innovate and to find new problem-solving solutions with an artificial feeding task in wild redfronted lemurs (Eulemur rufifrons). Four groups of lemurs were tested with feeding boxes, each offering three different techniques to extract food, with only one technique being available at a time. After the subjects learned a technique, this solution was no longer successful and subjects had to invent a new technique. For the first transition between task 1 and 2, subjects had to rely on their experience of the previous technique to solve task 2. For the second transition, subjects had to inhibit the previously learned technique to learn the new task 3. Tasks 1 and 2 were solved by most subjects, whereas task 3 was solved by only a few subjects. In this task, besides behavioral flexibility, especially persistence, i.e., constant trying, was important for individual success during innovation. Thus, wild strepsirrhine primates are able to innovate flexibly, suggesting a general ecological relevance of behavioral flexibility and persistence during innovation and problem solving across all primates.  
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  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1435-9456 ISBN (up) Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Equine Behaviour @ team @ Huebner2015 Serial 5938  
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Author Ihle, M.; Kempenaers, B.; Forstmeier, W. url  doi
openurl 
  Title Fitness Benefits of Mate Choice for Compatibility in a Socially Monogamous Species Type Journal Article
  Year 2015 Publication PLoS Biol Abbreviated Journal PLoS Biol  
  Volume 13 Issue 9 Pages e1002248  
  Keywords  
  Abstract Research on mate choice has primarily focused on preferences for quality indicators, assuming that all individuals show consensus about who is the most attractive. However, in some species, mating preferences seem largely individual-specific, suggesting that they might target genetic or behavioral compatibility. Few studies have quantified the fitness consequences of allowing versus preventing such idiosyncratic mate choice. Here, we report on an experiment that controls for variation in overall partner quality and show that zebra finch (Taeniopygia guttata) pairs that resulted from free mate choice achieved a 37% higher reproductive success than pairs that were forced to mate. Cross-fostering of freshly laid eggs showed that embryo mortality (before hatching) primarily depended on the identity of the genetic parents, whereas offspring mortality during the rearing period depended on foster-parent identity. Therefore, preventing mate choice should lead to an increase in embryo mortality if mate choice targets genetic compatibility (for embryo viability), and to an increase in offspring mortality if mate choice targets behavioral compatibility (for better rearing). We found that pairs from both treatments showed equal rates of embryo mortality, but chosen pairs were better at raising offspring. These results thus support the behavioral, but not the genetic, compatibility hypothesis. Further exploratory analyses reveal several differences in behavior and fitness components between “free-choice” and “forced” pairs.  
  Address  
  Corporate Author Thesis  
  Publisher Public Library of Science Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN (up) Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5959  
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Author Aurich, J.; Wulf, M.; Ille, N.; Erber, R.; von Lewinski, M.; Palme, R.; Aurich, C. url  doi
openurl 
  Title Effects of season, age, sex and housing on salivary cortisol concentrations in horses Type Journal Article
  Year 2015 Publication Domestic Animal Endocrinology Abbreviated Journal Domest. Anim. Endocrinol.  
  Volume Issue 0 Pages  
  Keywords horse; cortisol; diurnal rhythm; reproduction; housing  
  Abstract Abstract Analysis of salivary cortisol is increasingly used to assess stress responses in horses. Since spontaneous or experimentally induced increases in cortisol concentrations are often relatively small for stress studies proper controls are needed. This requires an understanding of factors affecting salivary cortisol over longer times. In this study, we have analysed salivary cortisol concentration over 6 mo in horses (n = 94) differing in age, sex, reproductive state and housing. Salivary cortisol followed a diurnal rhythm with highest concentrations in the morning and a decrease throughout the day (P < 0.001). This rhythm was disrupted in individual groups on individual days; however, alterations remained within the range of diurnal changes. Comparison between months showed highest cortisol concentrations in December (P < 0.001). Cortisol concentrations increased in breeding stallions during the breeding season (P < 0.001). No differences in salivary cortisol concentrations between non-pregnant mares with and without a corpus luteum existed. In stallions, mean daily salivary cortisol and plasma testosterone concentration were weakly correlated (r = 0.251, P < 0.01). No differences in salivary cortisol between female and male young horses and no consistent differences between horses of different age existed. Group housing and individual stabling did not affect salivary cortisol. In conclusion, salivary cortisol concentrations in horses follow a diurnal rhythm and are increased in active breeding sires. Time of the day and reproductive state of the horses are thus important for experiments that include analysis of cortisol in saliva.  
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  Corporate Author Thesis  
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  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0739-7240 ISBN (up) Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5847  
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Author Lovrovich, P.; Sighieri, C.; Baragli, P. url  doi
openurl 
  Title Following human-given cues or not? Horses (Equus caballus) get smarter and change strategy in a delayed three choice task Type Journal Article
  Year 2015 Publication Applied Animal Behaviour Science Abbreviated Journal Appl. Anim. Behav. Sci.  
  Volume 166 Issue Pages 80-88  
  Keywords  
  Abstract Highlights

&#65533;Horses remember the location of food hidden by the experimenter after a delay.
&#65533;They understand the communicative meaning of a human positioned close to the target.
&#65533;The same horses are capable of changing their decision-making strategy.
&#65533;They are able to shift from accuracy inferred from human given cues to speed.
&#65533;Horses can use human cues or not depending on time, cost, experience and reward.

Abstract

To date, horses have seemed capable of using human local enhancement cues only when the experimenter remains close to the reward, since they fail to understand the communicative meaning of the human as momentary local enhancement cue (when the human is not present at the moment of the animal's choice). This study was designed to analyse the ability of horses to understand, remember and use human-given cues in a delayed (10&#8197;s) three-choice task. Twelve horses (experimental group) had to find a piece of carrot hidden under one of three overturned buckets after seeing the experimenter hide it. The results were then compared with those of a control group (twelve horses) that had to find the carrot using only the sense of smell or random attempts. At the beginning, the experimental horses made more correct choices at the first attempt, although they took more time to find the carrot. Later the same horses were less accurate but found the carrot in less time. This suggests that the value of the proximal momentary local enhancement cues became less critical. It seemed, in fact, that the experimental and control group had aligned their behaviour as the trials proceeded. Despite this similarity, in the second half of the trials, the experimental group tended to first approach the bucket where they had found the carrot in the immediately preceding trial. Our findings indicate that horses are capable of remembering the location of food hidden by the experimenter after a delay, by using the human positioned close to the target as valuable information. The same horses are also capable of changing their decision-making strategy by shifting from the accuracy inferred from human given cues to speed. Therefore, horses are able to decide whether or not to use human given-cues, depending on a speed-accuracy trade-off.
 
  Address  
  Corporate Author Thesis  
  Publisher Elsevier Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
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  ISSN ISBN (up) Medium  
  Area Expedition Conference  
  Notes doi: 10.1016/j.applanim.2015.02.017 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5849  
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Author Giles, S.L.; Nicol, C.J.; Harris, P.A.; Rands, S.A. url  doi
openurl 
  Title Dominance rank is associated with body condition in outdoor-living domestic horses (Equus caballus) Type Journal Article
  Year 2015 Publication Applied Animal Behaviour Science Abbreviated Journal  
  Volume Issue 0 Pages  
  Keywords Equine; fatness; obesity; social behaviour; displacement  
  Abstract Abstract The aim of our study was to explore the association between dominance rank and body condition in outdoor group-living domestic horses, Equus caballus. Social interactions were recorded using a video camera during a feeding test, applied to 203 horses in 42 herds. Dominance rank was assigned to 194 individuals. The outcome variable body condition score (BCS) was recorded using a 9-point scale. The variables age and height were recorded and considered as potential confounders or effect modifiers. Results were analysed using multivariable linear and logistic regression techniques, controlling for herd group as a random effect. More dominant (p = 0.001) individuals generally had a higher body condition score (p = 0.001) and this association was entirely independent of age and height. In addition, a greater proportion of dominant individuals fell into the obese category (BCS >= 7/9, p = 0.005). There were more displacement encounters and a greater level of interactivity in herds that had less variation in age and height, lending strength to the hypothesis that phenotypic variation may aid cohesion in group-living species. In addition there was a strong quadratic relationship between age and dominance rank (p < 0.001), where middle-aged individuals were most likely to be dominant. These results are the first to link behavioural predictors to body condition and obesity status in horses and should prompt the future consideration of behavioural and social factors when evaluating clinical disease risk in group-living animals.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0168-1591 ISBN (up) Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Equine Behaviour @ team @ Giles2015 Serial 5864  
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Author Baumgartner, M.; Frank,V.; Gandorfer,J.; Ramoser, A.;Seiler, S.; Zeitler-Feicht, M.H. pdf  openurl
  Title Feasible animal-based indicators for assessing equine welfare Type Conference Article
  Year 2015 Publication Proceedings of the 3. International Equine Science Meeting Abbreviated Journal Proc. 3. Int. Equine. Sci. Mtg  
  Volume Issue Pages  
  Keywords  
  Abstract Introduction

Are horses doing well in their husbandries? For the first time the answer shall be given objectively by an integral on-farm welfare assessment system for horse husbandries. A current research project at the Technical University Munich evaluates indicators for well-being, pain and suffering in horses in order to develop a welfare assessment system (Baumgartner and Zeitler-Feicht 2013, 2014a, 2014b, 2015, Zeitler-Feicht et al. 2015). The research project is professionally supported by horse husbandry experts from academics, industries as well as leading organizations for horse owners and veterinarians.
The aim of the project is to develop a welfare assessment system for all horse husbandry systems which can be applied both for sport horses and for leisure horses. It is based on national animal welfare standards (BMELV 2009) and does take sustainability into consideration. Animal-based indicators are completed with resource-based indicators if necessary. It is stipulated that indicators are valid, reliable and feasible.
Welfare criteria were formulated for the two principles „good health“ and „behavioural demands“ (see figure 1 and 2). Each has to be represented by at least one indicator.
The principle „behavioural demands“ aims at the possibility for horses to practise species-specific behaviour. It is gathered to what extent the housing conditions allow the horses to live out and show species-specific behaviour. Furthermore in the present studies the frequency of selected behaviours including abnormal behaviour were collected in precise timeframes.
Potential indicators for assessing equine welfare on-farm were selected by study of literature and field tests. The field tests included direct observations on free-ranged horses, horses in group-housing systems and single-stabled horses. The following section presents selected indicators that are feasible for assessing equine behaviour on-farm.


Feasible behavioural indicators for well-being

The literature research revealed that „being together“ is linked with affiliative behaviour. It includes „resting together“, „foraging together“ and additionally „walking together“. Horses do have a strong need for social bonds. „Being-together“ amongst horses must be voluntary and not caused by bad weather conditions or lack of space. Therefore the context must be considered. For temporary direct observations the frequency in group-housing systems is sufficient (0.57 ± 0.67 per horse per 20 minutes). That´s why in our study „being-together“ is considered as a feasible indicator for well-being for horses in permanent or temporary groups. It is intended to conduct further studies on its validity.
Other behaviours such as „social play“ is not only linked with positive emotional states in adult horses. Several studies showed that horses use „social play“ as a stress relief. However, it is too seldom to collect in an on-farm assessment system. Because of the lack of feasibility and validity we excluded „social play“ as an indicator for well-being.


Feasible behavioural indicators for suffering

Horses show „abnormal behaviour“ in distress, frustration, deprivation or conflict situations. The present studies showed a relatively high frequency in single-stabled horses (3.3 ± 6.45 per horse per 20 minutes). Hence „abnormal behaviour“ is a feasible and valid indicator for suffering. However, established stereotypes need to be excluded, because they may indicate a previous welfare status rather than the current welfare status.
Horses use „agonistic behaviour“ to regulate social relations, to defend themselves or to defend resources. If husbandry or management is inadequate, „agonistic behaviour“ increases and thereby the frequency of injuries caused by social conflicts. A high frequency of „agonistic behaviour“ indicates a high aggression level in group-housed horses and therefore distress and suffering. The mean frequency of group-housed horses is sufficient for temporary observations (2.6 ± 2.26 per horse per 20 minutes). As a result „agonistic behaviour“ is a feasible and vaild indicator for suffering. Further studies need to be done on the scoring and severity.

Key words

Animal-based indicators
Equine welfare
Being-together
Abnormal behaviour
Agonistic behaviour


References

Baumgartner M. & M. H. Zeitler-Feicht (2013): Entwicklung eines Bewertungssystems zur Beurteilung der Tiergerechtheit von Pferdehaltungen als Bestandteil eines Nachhaltigkeitsmanagementsystems. KTBL Schrift: Aktuelle Arbeiten zur artgemäßen Tierhaltung 503, 226 – 227.
Baumgartner M. & M. H. Zeitler-Feicht (2014a): Indikatoren für Tierwohl beim Pferd. 7. Pferde-Workshop Uelzen 2014. DGfZ-Schriftreihe Heft 64, 161 – 166.
Baumgartner M. & M. H. Zeitler-Feicht (2014b): Entwicklung eines Bewertungssystems zur Beurteilung der Tiergerechtheit von Pferdehaltungen als Bestandteil eines Nachhaltigkeitsmanagementsystems. 9. Niedersächsisches Tierschutzsymposium in Oldenburg, Hrsg. Nds. Ministerium für Ernährung, Landwirtschaft und Verbraucherschutz, 37 – 42.
Baumgartner M. & M.H. Zeitler-Feicht (2015): Eignung ausgewählter tierbezogener Indikatoren zur Beurteilung der Tiergerechtheit von Pferdehaltungen hinsichtlich Praktikabilität. In: Tagungsband der Deutschen Veterinärmedizinischen Gesellschaft e.V. (DVG), Fachgruppen „Ethologie und Tierhaltung“ sowie „Tierschutz“, Verlag der DVG Service GmbH, Gießen, S. 182 – 192.
BMELV (2009): Leitlinien zur Beurteilung von Pferdehaltungen unter Tierschutzgesichtspunkten. Bundesministerium für Ernährung, Landwirtschaft und Verbraucherschutz. Sachverständigengruppe tierschutzgerechte Pferdehaltung.
Zeitler-Feicht M.H., Frank V., Ramoser A., Seiler S., Girisch C., Baumgartner M. (2015): Anhand welcher Verhaltensweisen lassen sich Rückschlüsse auf das Wohlbefinden von Pferden ziehen? In: Tagungsband der Deutschen Veterinärmedizinischen Gesellschaft e.V. (DVG), Fachgruppen „Ethologie und Tierhaltung“ sowie „Tierschutz“, Verlag der DVG Service GmbH, Gießen, S. 148 – 156.
 
  Address  
  Corporate Author Baumgartner,M. Thesis  
  Publisher Xenophon Publishing Place of Publication Wald Editor Krüger. K.  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN (up) Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5868  
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Author Wyss, C. pdf  openurl
  Title Does housing in a „social box“ change faecal cortisol metabolites concentration in stallions? Type Conference Article
  Year 2015 Publication Proceedings of the 3. International Equine Science Meeting Abbreviated Journal Proc. 3. Int. Equine. Sci. Mtg  
  Volume Issue Pages  
  Keywords housing system, stallions, social interaction, stress, faecal cortisol metabolites  
  Abstract In order to improve the housing conditions of stallions in individual boxes by offering a possibility to have more social contact, the Swiss national stud farm tested a new box system for horses, allowing increased physical contact with the neighbouring stallion. The aim of this part of the study was to investigate whether this type of housing system (named “social box”) potentially induces a change in stress reactions in stallions compared to conventional boxes. Therefore faecal cortisol metabolite (FCM) concentration was measured as a non-invasive parameter to assess endocrine responses related to this new environment.
Four groups each consisting of eight adult Freiberger breeding stallions were included in the test design. Every stallion spent three weeks in a conventional box and in a social box respectively (cross-over design). The conventional box consisted of a separation wall with a lower opaque part and an upper part with vertical barriers (5 cm between barriers), allowing visual and olfactory contact but strongly limiting tactile contact. The separating wall of the social box consisted of two lateral sections, one part being opaque to the ceiling and the second part consisting of vertical barriers (30 cm between barriers), allowing the horse to have physical contact with its neighbour or to avoid it.
In horses, FCM concentration reflects an average level of circulating cortisol over a period of approximatively 24h. Faecal samples were collected the day following integration in social / conventional boxes, reflecting the potential stress induced by increased social interactions during the integration. In order to asses potential chronical stress, faeces samples were also collected in week one, two and three after the integration into the social / conventional box (in total: 4 samples per horse and housing system). The samples were immediately stored at -20°C until they were analysed. The samples were not analysed in the laboratory until the end of the experiment, therefore the duration of conservation in the freezer varied from 40 to 429 days.
A considerable percentage of data from groups 1 and 2 was below the detection limit (<0.8 ng/g) (Tab. 1). Thus the statistical analysis was conducted with the FCM concentration from groups 3 and 4 (n horses = 16) which contained no values below the detection limit.

Tab. 1: Details about FCM values and storage time for the 4 groups of stallions
Group Storage duration [d] Proportion of data below the detection limit (<0.8 ng/g) Mean [ng/g] Median [ng/g]
Group 1 384-429 55.6 % 2.2 0
Group 2 315-360 25.5 % 5.8 6.3
Group 3 41-79 0.0 % 8.7 8.0
Group 4 40-85 0.0 % 5.8 5.4

Despite the impressive social interactions observed between the stallions directly after being introduced into the social boxes, we did not find any differences in FCM concentration between the stallions being introduced into the conventional box and the social box on the day of integration (social box: n samples = 16, mean±SD: 6.9±4.7 ng/g; conventional box: n samples = 16, mean±SD: 9.0±11.2 ng/g; Wilcoxon signed rank test V = 70, p = 0.94).
Overall the samples taken during integration and in week one, two and three did not show evidence of changes in FCM concentration in either housing system over a longer period of time (social box: n samples = 64, mean±SD: 7.9±6.2 ng/g; conventional box: n samples = 64, mean±SD: 6.6±3.4 ng/g; Linear mixed model (LMM), p = 0.56).
Our results suggest that the possibility of having physical contact with a conspecific does not induce changes in FCM concentration in breeding stallions. The considerable percentage of values below the detection limit in groups 1 and 2 seemed to correlate with the increasing duration of storage before analysis. During the IESM Network Meeting 2015, we would like to discuss possible methodological issues and the possibilities to correctly integrate these low values in the statistical analysis.
 
  Address  
  Corporate Author Wyss, C. Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
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  Area Expedition Conference  
  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5869  
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Author Medill, S.A; Janz, D.M.; McLoughlin, P.D. pdf  openurl
  Title Hair testosterone and cortisol concentrations and their relationships to physiological and social status in feral horses (Equus ferus caballus) Type Conference Article
  Year 2015 Publication Proceedings of the 3. International Equine Science Meeting Abbreviated Journal Proc. 3. Int. Equine. Sci. Mtg  
  Volume Issue Pages  
  Keywords  
  Abstract Determining steroid hormone concentrations in hair has been frequently performed in humans, and increasingly in wildlife and domestic animals. Hair hormone concentrations may provide insight on how individuals are responding to their physiological condition or social situation. Cortisol is most frequently measured in hair as a biomarker of long-term stress, while testosterone may be linked with reproductive status in males. These hormones are commonly measured in substances that reflect either current (e.g. blood) or very recent (e.g. saliva, urine, feces) circulating levels. However, these hormones are also incorporated into hair during hair growth and provide a chronological record of circulating hormone levels. Thus, analysis of steroid hormones in hair provides a much longer representation of an animal’s endocrine status than other tissues frequently targeted for non-invasive monitoring.
The feral horse (Equus ferus caballus) population on Sable Island, Nova Scotia, Canada, has been annually censused during the mid-late summer since 2008 to track individual life histories and population dynamics. We collected tail hair (n = 144 females, n = 162 males) from known individuals either opportunistically or from natural or artificial snags to investigate how hair cortisol and testosterone might be associated with physiological state (e.g. lactating vs. non-lactating, body condition, age), as well as their social situation (e.g. dominant band stallion, subordinate band stallion, or bachelor) and measures of sociality. The proximal 5 cm of hair (excluding first 4mm or root region) were ground to a fine powder and hormones extracted with methanol and analyzed by using enzyme-linked immunoassay.
Preliminary analyses of the data showed a general sex based difference in hair cortisol concentrations (females lower than males; t = 3.16, df = 317, P=0.002). Among females, the presence of nursing foals was accompanied by an increase in hair cortisol (z = 2.93, df =140, P = 0.003); however, no significant difference was found in hair cortisol concentrations based on sex of the foal (t = -0.06, df = 82, P = 0.95). Horses in poor body condition tended to have higher hair cortisol than those in good or excellent condition (slope= -0.203, df = 312, P = 0.003). We also observed an increased concentration of hair cortisol as horses increased in age from 3-6 or entered into reproductive maturity. Adult male dominant band stallions did not have significantly less cortisol than bachelors or subordinate stallions but these three groups were significantly greater than young males (aged 3 and 4) who generally do not challenge the older males for reproductive opportunities.
Additionally, we looked at hair testosterone concentrations for n=46 males. Testosterone is known to influence traits and behaviours that enhance sexual selection. Often there is an inverse relationship between cortisol levels and testosterone; in particular, being able to maintain high testosterone and not have elevated cortisol related to the metabolic costs of sexual trait production ensures that traits or behaviours honestly signal the quality of the individual. For this reason we’d expect to see band stallions (those males in a position to mate) have a lower value in the ratio Cortisol: Testosterone. Early indications suggest we see this phenomenon in feral horses.
As a relatively new approach in wildlife research, the use of hair hormone analysis shows promise in contributing to our understanding of physiological aspects of sexual selection and other processes. Additionally, hair hormone analysis may have applications in advancing knowledge of animal husbandry and in particular, welfare.
 
  Address  
  Corporate Author Medill, S.A. Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN (up) Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 5870  
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