Social behavior and welfare in horses (Equus caballus)

Thaana Van Dessel
Persbericht

Het verborgen leed van paarden

De laatste vijftig jaar is er een toename van het aantal mensen met paarden en een afname van het aantal paardenmensen.

Paarden maken al eeuwen deel uit van onze maatschappij, en nu is de paardensport nog populairder dan ooit. Maar hoe goed kennen we onze paarden eigenlijk? En in hoeverre weten we wel of ze gelukkig zijn? Hoe ervaren zij het leven dat we hun opleggen?

Ten einde het paard en zijn welzijnsnoden beter te begrijpen, heb ik tussen februari en mei 2018 een onderzoek gedaan naar het natuurlijk kuddegedrag van paarden, en naar de effecten van sociale isolatie. Het ultieme doel was om de ware aard van het paard naar voren te brengen, met als hoop dat de opgedane kennis een betere toekomst zou beteken voor gedomesticeerde paarden.
In de studie werden er twee onderzoekspopulaties ingezet: een kudde van veertien Akhal-Teke paarden, gehouden op 40 hectaren land in het Zuiden van Estland en een groep van negen IJslandse paarden gehuisvest op een paddock met inloopstal te Stabroek, België.

Resultaten

Vriendschap

De resultaten toonden dat paarden hoog sociale dieren zijn die frequent contact zoeken met hun kuddemaatjes. Zo zullen paarden elkaar krabben en poetsen, dicht bij elkaar gaan staan om te rusten of samen spelen. Bovendien nemen paarden van alle rang- en leeftijdscategorieën deel aan deze sociale interacties, wat betekend dat sociaal contact voor alle individuen zeer belangrijk is. Verder hebben we ondervonden dat paarden ook hechte vriendschappen vormen, in beide kuddes waren er meerdere duo’s die veel meer met elkaar omgingen dan met andere kuddeleden, bovendien waren deze ‘beste maatjes’ steeds van gelijke rangorde (bv. 1ste en 2de ; 12de en 13de in rang). En zowel hoog- als laag rankende paarden toonden de behoefte om hechte banden te vormen met andere paarden.

Isolatie

Tijdens de isolatie-test hebben we elke IJslander gedurende vijf minuten alleen op stal gezet. De afzondering wekte extreme stressreacties op, de dieren toonden allen signalen van abnormale spanning, angst en frustratie. Ze begonnen rusteloos over en weer te lopen, angstig rond te kijken, luid te briesen en te mesten. Sommige paarden probeerden de deur te forceren, anderen sloegen heftig tegen de grond met hun hoeven of begonnen in het rond te bokken. Zulke reacties ondanks het feit dat de afzondering enkel een paar minuten duurde vertalen ernstige stress en tonen aan dat sociale isolatie zware gevolgen kan hebben op de gemoedstoestand en het welzijn van paarden.

Groupshuisvesting, maar hoe? 

Als paarden niet geschikt zijn om een solitair leven te leiden, dan moeten ze wel in groep gehouden worden, maar op welke manier? Veel eigenaars houden hun (soms heel dure) paarden liever apart omdat ze ervan overtuigd zijn dat paarden onderling veel agressie naar elkaar tonen en dat er dus hoge kansen zijn op verwonding. Onze studie (en andere voorheen) toont echter dat paarden die in stabiele kuddes leven, vooral communiceren aan de hand van subtiele signalen en dat dominantie en agressie hoofdzakelijk worden geuit door dreigingen en neutrale benaderingen. Werkelijke contact-agressie (zoals bijten of schoppen) die zou kunnen resulteren in verwonding, vertegenwoordigde enkel 5% van alle agressieve gedragingen onder onze Akhal-Teke paarden. Dit was echter hoger bij de IJslanders (15%), en we hebben ondervonden dat de mate van agressie in een kudde sterk afhankelijk is van het menselijk beheer, van “hoe de paarden gehouden worden”. Zo kunnen er meerdere factoren inspelen op agressie:

Leefruimte

De contact-agressie was drie keer hoger (15% vs. 5%) in de kudde die op een kleiner oppervlak werd gehouden. Bovendien suggereren onze resultaten dat deze paddock-paarden veel meer agressie toonden in de context van ruimteverdediging dan de paarden die gehuisvest waren op een weide van 40ha. We vermoeden dus dat de factor omvang van leefruimte een considerabele rol speelt in de toename (of afname) van agressief gedrag. We hebben tevens ook gevonden dat ondergeschikte paarden meestal in periferie van de kudde bleven en dat anciënniteit gelinkt was aan rangorde, nieuwkomers zouden steeds een lage positie krijgen in de hiërarchie.
Onze resultaten wijzen er dus op dat – om agressie te verlagen en een goed welzijn te bekomen – elk individu over voldoende ruimte moet beschikken om zich te kunnen terugtrekken bij confrontaties en om zijn gewenste (en natuurlijke) interindividuele afstand te houden t.o.v. andere kudde leden. We suggereren ook dat er extra aandacht moet gegeven worden bij het introduceren van nieuwe paarden, en dat dit enkel gedaan mag worden wanneer er voldoende bewegingsruimte is voor de groep. In dit licht is het ook niet aangeraden om paarden regelmatig van groep te veranderen of “nu en dan” eens in een kudde te zetten.

Akhal-Teke paarden, Estland

Voedsel

In het wild foerageren paarden 60% - 70% van de dag. Onze kuddes, die quasi continu hooi ter beschikking hadden, aten gemiddeld 55% van de tijd dat ze geobserveerd werden, en op alle tijdstippen van de dag. Wat aantoont dat paarden in gevangenschap gelijke voederbehoeften hebben aan die van hun wilde soortgenoten. Ondanks de abundantie aan voedsel werd de meerderheid van agressief gedrag toch geuit in de context van voedsel(competitie), dit zou veroorzaakt kunnen zijn door de verspreiding van het voedsel: de onnatuurlijke opeenhoping zou de drang tot competitie en monopolisering van voedselbronnen opwekken waardoor hogere agressie geobserveerd wordt. Bijgevolg stellen we voor dat voedsel best op meerdere plaatsen wordt verspreid.

Wat kunnen we hieruit begrijpen?

De studie heeft aangetoond dat paarden hoog sociale dieren zijn die sterke vriendschapsbanden met elkaar vormen en acute stressreacties tonen wanneer ze worden geïsoleerd. Dit wijst erop dat paarden alleen houden ernstige gevolgen kan hebben voor hun welzijn. Bovendien blijkt dat leefruimte en voedselbeschikbaarheid zeer belangrijke factoren zijn voor kuddebeheer, gebrekkig management kan namelijk verhoogde stresslevels en onnodige conflicten veroorzaken.
We sluiten het artikel met een aantal welzijnssuggesties: 1) hou uw paard niet alleen 2) als u paard in groep leeft, geef dan de voorkeur aan a/ een ruime leefomgeving, b/een constante aanwezigheid van ruwvoer dat op verschillende plekken wordt verspreid en c/ aan minimale veranderingen in de samenstelling van de kudde.

Bibliografie

Alexander, S.L., Irvine, C.H.G., Livesey, J.H., Donald, R.A. (1988). Effect of isolation stress on concentrations of arginine vasopressin, α-melanocyte-stimulating hormone and ACTH in the pituitary venous effluent of the normal horse. J. Endocr., 116, 325 – 334.

Ayala, I., Marton, N.F., Silvan, G., Gutierrez-Panizo, C. Clavel, J.G., Illera, J.C. (2012). Cortisol, adrenocorticotropic hormone, serotonin, adrenaline and noradrenaline serum concentrations in relation to disease and stress in the horse. Research in Veterinary Science, 93(1); 103 – 107.

Back, W. & Clayton, H.M. (2013). Equine Locomotion (2nd Ed.). s.l.: Elsevier Health Sciences.

Barta, Z., Flynn, R., Giraldeau, L.A. (1997). Geometry for a selfish foraging group: genetic algorithm approach. Proceedings of the Royal Society of London, Series B, 264, 1233 – 1238.

Beever, E.A. (2013). Equus caballus datasheet. CABI Invasive Species Compendium. Accessed on December 10th, 2017 at: https://www.cabi.org/isc/datasheet/119345#3FF7D777-A6B2-479F-91CB-DCB38…

Benhajali, H.,  Richard-Yris, M.-A., Ezzaouia, M., Charfi, F., Hausberger, M. (2009). Foraging opportunity: a crucial criterion for horse welfare? Animal, 3 (9), 1308 – 1312.

Berger, J. (1979). “Predator Harassment” as a Defensive Strategy in Ungulates. The American Midland Naturalist, 102(1), 197 – 199.

Bertolino, S. (2003). Herd defensive behaviour of chamois, Rupicapra, in response to predation on the young by a golden eagle, Aquila chrysaetos. Zeitschrift für Jagdwissenschaft, 49(3), 233 – 236.

Boyd, L.E. (1991). The behavior of Przewalski’s horses and its importance to their management. Applied Animal Behaviour Science, 29 (1-4), 301 – 318.

Bradford, A. (2015). Horse Facts. Accessed on December 10th, 2017, at: https://www.livescience.com/50714-horse-facts.html

Briefer Freymond, S., Briefer, E.F., Niederhäusern, R.V., Bachmann, I. (2013). Pattern of Social Interactions after Group Integration: A Possibility to Keep Stallions in Group. PLoS ONE, 8(1).

Broom, D.M. and Zanella, A.J. (2004). Brain measures which tell us about animal welfare. Animal Welfare, 13, 41 – 45.

Budiansky, S. (1997). The Nature of Horses. s.l.: The Free Press.

Bukowski, J.A. & Aiello, S. (2016). Breeding and Reproduction of Horses. MSD Veterinary Manual. Accessed on December 10th 2017 at: http://www.msdvetmanual.com/horse-owners/routine-care-and-breeding-of-h… .

Bureau of Land Management (BLM). (2018). Program data. Accessed on July 24th, 2018 on the internet at: https://www.blm.gov/programs/wild-horse-and-burro/about-the-program/pro…

Burla, J-B., Ostertag, A., Patt, A., Bachmann, I., Hillmann, E. (2016). Effects of feeding management and group composition on agonistic behavior of group-housed horses. Applied Animal Behaviour Science, 176, 32 – 42.

Cameron, E.Z., Setsaas, T.H., Linklater, W.L. (2009). Social bonds between unrelated females increase reproductive success in feral horses. PNAS, 106 (33).

Christensen, J.W., Søndergaard, E., Thodberg, K., Halekoh, U. (2011). Effects of repeated regrouping on horse behaviour and injuries. Applied Animal Behaviour Science, 133 (3-4), 199 – 206.

Christman, M.C. & Lewis, D. (2005). Spatial distribution of dominant animals within a group: comparison of four statistical tests of location. Animal Behaviour, 70(1), 73 – 82.

Clement, C. (2015). Equus caballus. Animal Diversity Web. Accessed on December 10th, 2017 at: http://animaldiversity.org/accounts/Equus_caballus/

Cooper J. & McGreevy P. (2007). Stereotypic Behaviour in the Stabled Horse: Causes, Effects and Prevention without Compromising Horse Welfare. In: Waran N. (eds) The Welfare of Horses. Animal Welfare, vol 1. Dordrecht: Springer.

Cozzi, A., Sighieri, C., Gazzano, A., Nicol, C.J., Baragli, P. (2010). Post-conflict friendly reunion in a permanent group of horses (Equus caballus). Behavioural Processes, 85(2), 185 – 190.

Craig, J.V. (1986). Measuring Social Behavior: Social Dominance. Journal of Animal Science, 62 (4), 1120 – 1129.

Cronin, G.M., Wiepkema, P.R., van Ree, J.M. (1986). Endorphins implicated in stereotypies in tethered sows. Experientia, 42(2), 198 – 199.

Crowell-Davis, S.L., Houpt, K.A., Kane, L. (1987). Play development in Welsh pony (Equus caballus) foals. Applied Animal Behaviour Science, 18(2), 119 – 131.

De Vries, H. (1998). Finding a dominance order most consistent with a linear hierarchy: a new procedure and review. Animal Behaviour, 55, 827–843.

De Vries, H., Stevens, J., Vervaecke, H. (2006). How to measure steepness: A new method to measure steepness of dominance hierarchies. Animal Behaviour 71: 585-592

Dhabhar, D.S. (2002). Stress-induced augmentation of immune function—The role of stress hormones, leukocyte trafficking, and cytokines. Brain, Behavior, and Immunity, 16(6), 785 – 798.

Ellard, M-E. & Crowell-Davis, S.L. (1989). Evaluating equine dominance in draft mares. Applied Animal Behaviour Science, 24 (1), 55 – 75.

EquiMed Staff. (2015). Sexual Maturity in Stallions and Mares – What You Need to Know. EquiMed. Accessed on December 10th 2017, at: http://equimed.com/health-centers/reproductive-care/sexual-maturity-in-…

Estes, R. (1991). The Behavior guide to African Mammals: Including Hoofed Mammals, Carnivores, Primates. s.l.: University of California Press.  

Estevez, I., Andersen, I-L, Naeval, E. (2007). Group size, density and social dynamics in farm animals. Applied Animal Behaviour Science, 103 (3-4), 185 – 204.

Fagen, R.M. & George, T.K. (1977). Play behavior and exercice in young ponies (Equus caballus L.). Behavioral Ecology and Sociobiology, 2(3), 267 – 269.

Feh, C. & De Mazières, J. (1993). Grooming at a preferred site reduces heart rate in horses. Anim Behav., 46, 1191 – 1194.

Feh, C. (1999). Alliances and reproductive success in Camargue stallions. 57(3), 705 – 713.         

Feh, C. (s.a.). Relationships and Communication in Socially Natural Horse Herds. Accessed on December 10th, 2017 at: http://research.vet.upenn.edu/Default.aspx?TabId=3119

Flauger, B. & Krueger, K. (2013). Aggression level and enclosure size in horses (Equus caballus). Pferdeheilkunde 29 (4), 495 – 504.

Fry, J. (2007). Backyard Horsekeeping: The Only Guide You’ll Ever Need. s.l.: Rownan & Littlefield.

Fureix, C., Bourjade, M., Henry, S., Sankey, C., Hausberger, M. (2012). Exploring aggression regulation in managed groups of horses Equus caballus. Applied Animal Behaviour Science, 138 (3-4), 216 – 228.

Garwicz, M., Christensson, M., Psouni, E. (2009). A unifying model for timing of walking onset in humans and other mammals. Proceedings of the National Academy of Sciences of the Unites States of America, vol. 106 (51).

Gibbons, J.M., Lawrence, A.B., Haskell, M.J. (2010). Measuring sociability in dairy cows. Applied Animal Behaviour Science, 122 (2-4), 84 – 91.

Giles, S.L., Nicol, C.J., Harris, P.A., Rands, S.A. (2015). Dominance rank is associated with body condition in outdoor-living domestic horses (Equus caballus). Applied Animal Behaviour Science, 166, 71 – 79.

GISD (Global Invasive Species Database). (2017). Species profile: Equus caballus. Accessed on December 10th, 2017 at: http://www.iucngisd.org/gisd/species.php?sc=1632

Goodwin D. (2007) Horse Behaviour: Evolution, Domestication and Feralisation. In: Waran N. (eds) The Welfare of Horses. Animal Welfare, 1, Springer : Dordrecht.

Grandin, T., McGee, K., Lanier, J.L. (1999). Prevalence of severe welfare problems in horses that arrive at slaughter plants. Journal of the American Veterinary Medical Association, 214 (10), 1531 – 1533.

Grogan, E.H. & McDonnel, S.M. (2005). Injuries and blemishes in a semi-feral herd of ponies. Journal of Equine Veterinary Science, 25 (1), 26 – 30.

Grubb, P. (2005). Order Perissodactyla. In: Mammal Species of the World. A Taxonomic and Geographic Reference (3rd ed.) [ed. by Wilson, D. E. \Reeder, D. M.]. Baltimore, Maryland, USA: Johns Hopkins University Press.

Hamilton, W.D. (1971). Geometry for the selfish herd. Journal of Theoretical Biology, 31(2), 295 – 311.

Hampson, B.A., de Laat, M.A., Mills, P.C., Pollitt, C.C. (2010). Distances travelled by feral horses in “outback” Australia. Equine Vet J Suppl., 38, 582 – 586.

Harewood, E.J. and McGowan, C.M. (2005). Behavioral and physiological responses to stabling naïve horses. Journal of Equine Veterinary Science, 25(4), 164 – 170. 

Hartmann, E., Christensen, J.W., McGreevy, P.D. (2017). Dominance and Leadership: Useful Concepts in Human – Horse Interactions? Journal of Equine Veterinary Science, 52, 1 – 9.

Hartmann, E., Søndergaard, E., Keeling, L.J. (2012). Keeping horses in groups: A review. Applied Animal Behaviour Science, 136(2-4), 77 – 87.

Hausberger, M., Fureix, C., Bourjade, M., Wessel-Robert, S., Richard-Yris, M-A. (2012). On the significance of adult play: what does social play tell us about adult horse welfare? Naturwissenschaften, 99(4), 291 – 302.

Hausberger, M., Gautier, E., Müller, C., Jego, P. (2007). Lower learning abilities in stereotypic horses. Applied Animal Behaviour Science, 107(3-4), 299 – 306.

Hausberger, M., Roche, H., Henry, S., Visser, E.K. (2008). A review of the human – horse relationship. Applied Animal Behaviour Science, 109(1), 1 – 24.

Heard, D.C. (1992). The Effect of Wolf Predation and Snow Cover on Musk-ox Group Size. The American Naturalist, 139(1), 190 – 204.

Heitor, F. & Vicente, L. (2010). Affiliative relationships among Sorraia mares: influence of age, dominance, kinship and reproductive state. Journal of Ethology, 28 (1), 133 – 140.

Heitor, F., do Mar Oom, M., Vicente, L. (2006a). Social relationships in a herd of Sorraia horses: Part I. Correlates of social dominance and contexts of aggression. Behavioural Processes, 73 (2), 170 – 177.

Heitor, F., do Mar Oom, M., Vicente, L. (2006b). Social relationships in a herd of Sorraia horses Part II. Factors affecting affiliative relationships and sexual behaviours. Behavioural Processes, 73(3), 231 – 239.

Held, S.D.E., Spinka, M. (2011). Animal play and animal welfare. Animal behavior, 81(4), 891 – 899.

Hemelrijk, C.K. (2000). Towards the integration of social dominance and spatial structure. Animal Behaviour, 59 (5), 1035 – 1048.

Henderson, A.J.Z. (2007). Don’t Fence Me In: Managing Psychological Well Being for Elite Performance Horses. Journal of Applied Animal Welfare Science.

Herberholz, J. & Marquart, G.D. (2012). Decision Making and Behavioral Choice during Predator Avoidance. Frontiers in Neuroscience, 6, 125.

Hogan, E.S., Houpt, K.A., Sweeney, K. (1988). The effect of enclosure size on social interactions and daily activity patterns of the captive Asiatic wild horse (Equus przewalskii). Applied Animal Behaviour Science, 21 (1-2), 147 – 168.

Houpt, K. A. & Wolski, T. R. (1980), Stability of equine hierarchies and the prevention of dominance related aggression. Equine Veterinary Journal, 12, 15–18.

Houpt, K.A., Law, K., Martinisi, V. (1978). Dominance hierarchies in domestic horses. Applied Animal Ethology, 4 (3), 273-283.

Ingólfsdóttir, H.B. & Sigurjónsdóttir, H. (2008). The benefits of high rank in the wintertime – A study of the Icelandic horse. Applied Animal Behaviour Science, 114 (3), 485 – 491.

Janson, C.H. (1990). Social correlates of individual spatial choice in foraging groups of brown capuchin monkeys, Cebus apella. Animal Behaviour, 40 (5), 910 – 921.

Jørgensen, G.H.M., Borsheim, L., Mejdell, C.M., Søndergaard, E., Bøe, K.E. (2009). Grouping horses according to gender – Effects on aggression, spacing and injuries. Applied Animal Behaviour Science, 120 (1), 94 – 99.

Jørgensen, G.H.M., Mejdell, C.M. Bøe, K.E. (2015). Group housing of horses – animal welfare and human safety. IGN Fokus, autumn 2015, 25 – 27.

Keeling, J.K. (2001). Social Behavior in Farm Animals. Wallingford: CABI Publishing.

Keiper, R. & Receveur, H. (1992). Social interactions of free-ranging Przewalski horses in semi-reserves in the Netherlands. Applied Animal Behaviour Science, 33 (4) , 303 – 318.

Keiper, R.R. & Sambraus, H.H. (1986). The stability of equine dominance hierarchies and the effects of kinship, proximity and foaling status on hierarchy rank. Applied Animal Behaviour Science, 16 (2), 121 – 130.

Keiper, R.R. (1986). Social Structure. Veterinary Clinics of North America: Equine Practices, 2(3), 465 – 484.

Keiper, R.R. (1988). Social interactions of the Przewalski horse (Equus przewalskii Poliakov, 1881) herd at the Munich Zoo. Applied Animal Behaviour Science, 21(1-2), 89 – 97.

Kie, J.G. (1999). Optimal Foraging and Risk of Predation: Effects on Behavior and Social Structure in Ungulates. Journal of Mammalogy, 80(4), 1114 – 1129.

Kilby, E.R. (2007). The demographics of the U.S. equine population. In: Salem, D.J.  & Rowan, A.N. (Eds.). The state of the animals, pp. 175-205. Washington, DC: Humane Society Press.

Kimura, R. (1998). Mutual grooming and preferred associate relationships in a band of free-ranging horses. Applied Animal Behaviour Science, 59(4), 265 – 276.

King, A.J., Wilson, A.M., Wilshin, S.D., Lowe, J., Haddadi, H., Hailes, S., Morton, A.J. (2012). Selfish-herd behavior in sheep under threat. Current Biology, 22(14), 561 – 562.

Klimov, V.V. (1988). Spatial-ethological organization of the herd of Przewalski horses (Equus przewalskii) in Askania-Nova. Applied Animal Behaviour Science, Volume 21, Issue 1, 99 – 115

Knubben, J.M., Fürst, A., Gygax, L., Stauffacher, M. (2008). Bite and kick injuries in horses: Prevalence, risk factors and prevention. Equine Veterinary Journal, 40(3), 219 – 223.

Komarkova, M, Bartosova, J., Dubcova, J. (2014). Age and group residence but not maternal dominance affect dominance rank in young domestic horses. J Animal Sci, 92 (11).

Krueger, K. & Heinze, J. (2008). Horse sense: social status of horses (Equus caballus) affects their likelihood of copying other horses’ behavior. Animal Cognition, 11 (3), 431 – 439.

Krueger, K., Flauger, B., Farmer, K., Hemelrijk, C. (2014). Movement initiation in groups of feral horses. Behavioural Processes, 103, 91 – 101.

Lamoot, I. & Hoffmann, M. (2004). Do season and habitat influence the behavior of Haflinger mares in a coastal dune area? Belg. J. Zool., 134(2), 97 – 103.

Landsberg, G.M. (s.a.). Social Behavior of Horses. Merck Veterinary Manual. Accessed on December 10th 2017 at: http://www.merckvetmanual.com/behavior/normal-social-behavior-and-behav…

Lansade, L., Bouissou, M-F., Erhard, H.W. (2008). Reactivity to isolation and association with conspecifics: A temperament trait stable across time and situations. Applied Animal Behaviour Science, 109, 355-373.

Linklater, W.L., Cameron, E.Z., Minot, E.O., Stafford, K.J. (1999). Stallion harassment and the mating system of horses. Anim Behav., 58(2), 295 – 306.

Luescher, U.A., McKeown, D.B., Halip, J. (1991). Reviewing the causes of obsessive compulsive disorders in horses. Veterinary Medicine, 86, 527 – 530.

Mal, M.E., Friend, T.H., Lay, D.C., Vogelsang, S.G., Jenkins, O.C. (1991). Physiological responses of mares to short term confinement and social isolation. Journal of Equine Veterinary Science, 11(2), 96 – 102.

Marcum, C.S. (2013). Age Differences in Daily Social Activities. Res. Aging, 35-5, 612 – 640.

Mascaro, O. & Csibra, G. (2014). Human Infants’ Learning of Social Structures: The Case of Dominance Hierarchy. Psychol. Sci., 25(1), 250 – 255.

Mason, G. & Rushen, J. (2006). Stereotypic Animal Behaviour: Fundamentals and Applications to Welfare (2de dr.). s.l.: CABI.

Mason, G.J. (1991a). Stereotypies: a critical review. Animal Behaviour, 41 (6), 1015 – 1037.

Mason, G.J. (1991b). Stereotypies and suffering. Behavioural Processes, 25 (2 – 3), 103 – 115.

McAfee, L.M., Mills, D.S., Cooper, J.J. (2002). The use of mirrors for the control of stereotypic weaving behavior in the stabled horse. Applied Animal Behaviour Science, 78(2-4), 159 – 173.

McAllister, R. (2008). The Heartbreak of Separation Anxiety. Consulted on June 25th 2018 on the internet: https://thehorse.com/124719/the-heartbreak-of-separation-anxiety/.

McBride, S.D. & Cuddeford, D. (2001). The Putative Welfare-Reducing Effects of Preventing Equine Stereotypic Behaviour. Animal Welfare, 10(2), 173 – 189.

McCall, C.A., Hall, S., McElhenney, W.H., Cummins, K.A. (2006). Evalutation and comparison of four methods of ranking horses based on reactivity. Applied Animal Behaviour Science, 96(1-2), 115 – 127.

McDonald Pavelka, M.S. (1991). Sociability in Old Female Japanese Monkeys: Human versus Nonhuman Primate Aging. American Anthropologist, 93(3), 588 – 598.

McDonnell, S.M. (2003). The Equid Ethogram: A Practical Field Guide to Horse Behavior. s.l.: Eclipse Press.

McGowan, C. (2011). Welfare of Aged Horses. Animals (Basel), 1(4), 366 – 376.

McGreevy, P. (2012). Equine Behavior, A Guide for Veterinarians and Equine Scientists, 2: Equine Behavior. s.l.: Elsevier Health Sciences.

McGreevy, P.D. & Nicol, C.J. (1998). Prevention of crib-biting: a review. Equine Veterinary Journal, 30(27), 35 – 38.

McKinnon, A.O., Squires, E.L., Vaala, W.E., Varner, D.D. (2011). Equine Reproduction (2nd ed.). s.l.: John Wiley & Sons.

Miller, R. (1983). Seasonal Movements and Home Ranges of Feral Horse Bands in Wyoming’s Red Desert. Journal of Range Management, 36(2), 199 – 201.

Mills, D. & Davenport, K. (2002). The effect of a neighbouring conspecific versus the use of a mirror for the control of stereotypic weaving behaviour in the stabled horse. Animal Science, 74(1), 95 – 101.

Mills, D.S. & McDonnel, S.M. (2005). The Domestic Horse: The Origins, Development and Management of Its Behaviour. s.l.: Cambridge Univeristy Press.

Mooring, M.S. & Hart, B.L. (1992). Animal Grouping for Protection From Parasites: Selfish Herd and Encounter-Dilution Effects. Behaviour, 123(3), 173 – 193.

Morrell, L.J. Ruxton, G.D., James, R. (2011). Spatial positioning in the selfish herd. Behavioral Ecology, 22(1), 16 – 22.

Möstl, E., Palme, R. (2002). Hormones as indicators of stress. Domestic Animal Endocrinology, 23(1-2), 67 – 74.

Nicol, C. (1999). Understanding equine stereotypies. Equine veterinary Journal, 28, 20 – 25.

Normando, S., Haverbeke, A., Meers, L., Odberg, D., Ibaned Tallegon, M. (2002). Heart rate reduction by grooming in horses. Proceedings of the Havermeyer Workshop on Horse Behaviour and Welfare, 23 – 26.

Normando, S., Haverbeke, A., Meers, L., Ödberg, F.O., Ibáñez Talegón, M., Bono, G. (2003). Effect of Manual Imitation of Grooming on Riding Horses' Heart Rate in Different Environmental Situations. Veterinary Research Communications, 27(1), 615 – 617.

Novaro, A., Moraga, C., Briceñ O, C., Funes, M., Marino, A., Steppe, A. (2009). First records of culpeo (Lycalopex culpaeus) attacks and cooperative defense by guanacos (Lama guanicoe). Mammalia, 73(2), 148 – 150.

NPS: National Park Service. (2015). Muskox : Circle Defense. Consulted online on June 12th 2018 on; https://www.nps.gov/gaar/learn/nature/muskox-circle-defense.htm

Overall, K.L. (s.a.). Normal Social Behavior in Horses. MSD Veterinary Manual. Accessed on December 10th, 2017 at: http://www.msdvetmanual.com/horse-owners/behavior-of-horses/normal-soci…

Pierard, M., McGreevy, P., Geers, R. (2018). Effect of density and relative aggressiveness on agonistic and affiliative interactions in a newly formed group of horses. Journal of Veterinary Behavior, in Press, available online 9 April, 2018.

Proops, L., McComb, K., Reby, D. (2009). Cross-modal individual recognition in domestic horses (Equus caballus). PNAD, 106(3), 947 – 951.

Pulliam, H.R. (1973). On the advantages of flocking. Journal of Theoretical Biology, 38(2), 419 – 422.

Ransom, J.I. and Cade, B.S. (2009) Quantifying equid behavior— A research ethogram for free-roaming feral horses. U.S. Geological Survey Techniques and Methods, 2-A9, 23p.

Rendon, R.A., Shuster, L., Dodman, N.H. (2001). The effect of the NMDA receptor blocker, dextromethorphan, on cribbing in horses. Pharmacology Biochemistry and Behavior, 68(1), 49 – 51.

Rho, J.R., Sryngley, R.B., Chloe, J.C. (2007). Sex preferences in Jeju pony foals (Equus caballus) for mutual grooming and play-fighting behaviors. Zoological Science, 24(8), 769 – 773.

Roggen, E.L., Corsini, E., van Loveren, H., Luebke, R. (2014). Chapter 3.1 – Immunotoxicity Testing: Implementation of Mechanistic Understanding, Key Pathways of Toxicological Concern, and Components of These Pathways. In: Toxicogenomics-Based Cellular Models (Pp.57 – 65.). s.l.: Academic Press.

Rubenstein, D. (1978). On Predation, Competition, and the Advantages of Group Living. Perspectives in Ethology, 3, 205 – 231.

Rutberg, A.T. & Greenberg, S.A. (1990). Dominance, aggression frequencies and modes of aggressive competition in feral pony mares. Animal Behaviour, 40 (2), 322 – 331.

Sankey, C., Richard-Yris, M-A., Leroy, H., Henry, S., Hausberger, M. (2010).  Positive interactions lead to lasting positive memories in horses Equus caballus. Animal Behaviour, 79(4), 869 – 875.

Sarrafchi, A. & Blokhuis, H.J. (2013). Equine stereotypic behaviors: Causation, occurrence, and prevention. Journal of Veterinary behavior: Clinical Applications and Research, 8(5), 386 – 394.

Sellnow, S. (2013). Growing Up: Estimating Adult Size. The Horse. Accessed on December 10th, 2017 at: http://www.thehorse.com/articles/10228/growing-up-estimating-adult-size

Shank, C.C. (1977). Cooperative Defense by Bighorn Sheep. Journal of Mammalogy, 58(2), 243 – 244.

Sibbald, A.M., Elston, D.A., Smith, D.J.F., Erhard, H.W. (2005). A method for assessing the relative sociability of individuals within groups: an example with grazing sheep. Applied Animal Behaviour Science, 91 (1-2), 57 – 73.

Sigurjónsdóttir, H., van Dierendonck, M.C., Snorrason, S., Thórhallsdóttir, A.G. (2003). Social relationships in a group of horses without a mature stallion. 140 (6), 783 – 804.

Sigurjónsdóttir, H., Van Dierendonck, M.C., Thórhallsdóttir, A.G. (2002). Friendship among horses: Rank and kinship matter. Proceedings of the Dorothy Russel Havemeyer Foundation Workshop, Horse behaviour and welfare.

Søndergaard, E., Bak Jensen, M., Nicol, C.J. (2011). Motivation for social contact in horses measured by operant conditioning. Applied Animal Behaviour Science, 132(3-4), 131 – 137.

Spinka, M., Newberry, R.C., Bekoff, M. (2001). Mammalian Play: Training for the Unexpected. The Quarterly Review of Biology, 76(2), 141 – 168.

Turner Jr, J.W. (2015). Environmental influences on movements and distribution of wild horse (Equus caballus) population in western Nevada, USA: a 25-year study. Journal of Natural History, 49(39-40), 2437 – 2464.

Turner, A.S., White, N., Ismay, J. (1984). Modified Forssell’s operation for crib biting in horses. J. Am. Vet. Med. Assoc., 184(3), 309 – 312.

van den Berg, M. (s.a.). Dietary Changes and The Evolution of The Horse. MB Equine Services. Accessed on December 10th, 2017, at: http://www.mbequineservices.com/dietary-changes-and-the-evolution-of-th…

Van Dierendonck, M.C. (2006). The importance of social relationships in horses. Dissertation, Utrecht University.

Van Dierendonck, M.C., De Vries, H., Schilder, M.B.H. (1994). An Analysis of domincance, Its Behavioural Parameters and Possible Determinants in a Herd of Icelandic Horses in Captivity. Netherlands Journal of Zoology, 45, 362-385.

Van Dierendonck, M.C., Sigurjónsdóttir, H., Colenbrander, B., Thorhallsdóttir, A.G. (2004). Differences in social behavior between late pregnant, post-partum and barren mares in a herd of Icelandic horses. Applied Animal Behaviour Science, 89(3-4), 283 – 297

Van Dierendonck, M.C., Spruijt, B.M. (2012). Coping in groups of domestic horses – Review from a social and neurobiological perspective. Applied Animal Behaviour Science, 138 (3 – 4), 194 – 202.

Vehrencamp, S.L. (1983). A model for the evolution of despotic versus egalitarian societies. Animal Behaviour, 31 (3), 667 – 682.

Vervaecke, H., Stevens, J.M.G., Vandemoortele, H., Sigurjónsdóttir, H., De Vries, H. (2007). Agression and dominance in matched groups of subadult Icelandic horses (Equus caballus). Journal of Ethologyn 25(3), 239 – 248.

Vervuert, I., Coenen, M. (2002). Feeding and housing management in horses.Pferdeheilkunde, 18, 629 – 663.

Visser, E.K., Ellis, A.D., Van Reenen, C.G. (2008). The effect of two different housing conditions on the welfare of young horses stabled for the first time. Applied Animal Behaviour Science, 114(3-4), 521 – 533.

Waring, G.H. (2003). Horse Behavior (2nd Ed.). Norwich, N.Y.: Noyes Publications.

Waters, A.J., Nicol, C.J., French, N.P. (2010). Factors influencing the development of stereotypic and redirected behaviours in young horses: findings of a four year prospective epidemiological study. Equine Veterinary Journal, 34(6), 572 – 579.

Wells, S. M., & von Goldschmidt-Rothschild, B. (1979). Social behaviour and relationships in a herd of Camargue horses. Zeitschrift für Tierpsychologie, 49(4), 363-380.

Whitaker, J.O. and Hamilton, W.J. (1998). Mammals of the Eastern United States. s.l.: Cornell University Press.

Whitehead, H. 2009. SOCPROG programs: analyzing animal social structures. Behavioral Ecology and Sociobiology 63: 765-778.

Williams, C.A. (2004). The Basics of Equine Behavior. Ruthers New Hersey Agricultural Experiment Station. Accessed on December 10th, 2017 at: http://esc.rutgers.edu/fact_sheet/the-basics-of-equine-behavior/

Willoughby, D.P. (1974). The Empire of Equus. New York: A.S. Barnes and Company.

Zabek, M.A., Berman, D.M., Blomberg, S. Wright, J. (2016). Estimating distribution and abundance of feral horses (Equus caballus) in a coniferous plantation in Australia, using line-transect surveys of dung. Wildlife Research 43(7): 604 – 614.

Zanella, A.J., Broom, D.M., Hunter, J.C., Mendl, M.T. (1996). Brain opioid receptors in relation to stereotypies, inactivity, and housing in sows. Physiology & Behavior, 59(4 – 5), 769 – 775.

Universiteit of Hogeschool
Agro- en biotechnologie
Publicatiejaar
2018
Promotor(en)
Hilde Vervaecke
Kernwoorden
Share this on: