Presenttion in session H11.5 * The ehviour of horses in different pddock sizes, with nd without exercise G.H.M. Jørgensen * & K.E. Bøe. Deprtment of Animl nd Aquculturl Sciences, Norwegin University of life Science, PO-Box 5003. N-1432 Ås, Norwy. * Corresponding uthor: Grete Helen Meisfjord Jørgensen, grete.meisfjord@um.no, Telephone: +47 64 96 51 42 Fx: +47 64 96 51 01 Introduction Documenttion on horse mngement in Norwy is scrce, ut in Switzerlnd, Sweden nd Denmrk most horses re kept individully with restricted turnout in pddocks (Bchmnn nd Stuffcher, 2002; Søndergrd, et l., 2002; Sttens Jordruksverk, 2004). Swedish recommendtions stte tht n individul pddock should mesure t lest 300 m 2 (Ventorp nd Michnek, 1997), ut Dnish recommendtions suggest 800 m 2 nd in ddition horses re recommended kept together in socil groups (Søndergrd et l., 2002). There is, however little evidence to confirm tht these individul pddock sizes re dequte for exercise nd other ctivities. For Przewlski horses kept in groups, results indicte tht horses in smller pddock sizes perform more milling, pcing, ggression, nd less resting, compred to when in lrger pddocks (Boyd, 1988; Hogn et l., 1988). The im of this experiment ws to investigte the effect of dily exercise nd pddock size on the ehviour of individully kept horses. It ws hypothesized tht the generl ctivity in the pddock would decrese when horses were exercised, nd tht the horses would perform more running nd plying in lrger pddock size compred to smller pddock size. Mteril nd methods Experimentl design The experiment ws conducted during the summer of 2004, t the Norwegin Equine Centre (Strum), nd it ws designed s 2 x 3 fctoril experiment with exercise (no exercise / dily exercise) nd pddock size (smll: 150 m 2, medium: 300 m 2 nd lrge: 450 m 2 ) s min fctors. In oth the no exercise (three weeks) nd the exercise (three weeks) tretment periods, nine horses were exposed to ll the three pddock sizes (one week for ech pddock size tretment) for 2 hours dily. The order of pddock size tretments ws rotted systemticlly. The three pddocks mesured 10 x 15 m (smll), 10 x 30 m (medium) nd 10 x 45 m (lrge) respectively nd hd sndy soil ground with some grss nd green plnts growing on the outside of the fence, ll round the perimeter of the pddock. Every dy the horses were fed, exercised for 45 minutes dily in circulr wlker (Kondi triner, dimeter * This mnuscript is sed on mnuscript ccepted s short communiction in the journl Applied Animl Behviour Science.
20 m) t speed of pproximtely 75 m/min (only in the exercise period) nd then turned out to the pddocks. Animls nd feeding Nine helthy horses (10-22 yers old) from oth cold- (CB) nd wrm-looded (WB) reed types were selected. There were oth mres (3) nd geldings (6) nd ll horses were normlly used in schooling, either riding or crrige driving. The horses were stled in tie-stlls mesuring 1.87 x 2.50 m in the sme uilding, nd they were fed individully djusted rtions of good qulity hy (6-8 kg per dy) four times dy, in ddition to ot grin nd rley pellets, three times dy, while housed. Behviourl oservtions Direct oservtions were done y present oserver locted in nery uilding overlooking the pddock re, for two hours in the pddocks t the lst two dys of ech pddock tretment period. The following mutully exclusive ehviourl clsses were scored using instntneous smpling t one-minute intervls: Stnding, wlking, running, vigorous ply, explortion, eting grss, stnding lert, self- grooming, rolling, defection, stnding sleep, digging the ground, eting/ licking soil, eting/ licking the wooden fence. In order to simultneously score the position of the horse, the pddocks were divided into squres mrked with spry pint on the ground. This llowed us to clculte the numer of squres crossed during the two hours nd to give rough estimte of the distnce trvelled y the ssumption tht the horses moved from the centre of one squre to the centre of nother. This will of course overestimte the pproximte distnce trvelled. Wether conditions Every dy ir temperture, wind speed nd precipittion ws recorded for every oservtion session nd ctegorised into four ctegories ccording to the chilling effect: 1: 5 10 C, strong wind nd moderte to hevy rin (n = 9), 2: 10 15 C, no or slight wind, moderte rin (n = 45), 3: 10 15 C, no or slight wind, no rin (n = 30), 4: 15 25 C, no or slight wind, no rin (n = 18). Sttistics In order to test the effect of different pddock sizes nd exercise on the horses ctivity, GLM-model ws used including the clss vriles pddock size (smll, medium, lrge), exercise (exercise,/ no exercise), dy of oservtion (dy 1, dy 2), week (1, 2, 3), wether (ctegories 1, 2, 3 or 4) nd individul niml (Htcher nd Stepnski, 1994). Lest squre mens ws used to test differences etween mens. Results In the non-exercise tretment period the horses wlked significntly more, they trvelled longer distnce, explored more nd stood more lert in the pddock thn in the period with exercise (Tle 1).
Tle 1. Effect of pddock size nd exercise on horse ctivity. Mens with different letters differ significntly,,c P<0.001, d,e, f P<0.05. Behviour (mens ± SE % Pddock size Exercise of os.) Smll Medium Lrge P-vlue No exercise Exercise P-vlue Stnding 61.8 ± 3.7 50.0 ± 4.0 34.2 ± 4.3 c < 0.0001 44.4 ± 3.6 d 52.9 ± 3.5 e 0.01 Wlking 6.0 ± 0.9 7.2 ± 1.4 8.3 ± 1.7 0.3 9.3 ± 1.4 d 5.1 ± 0.6 e 0.01 Explortion 2.7 ± 0.4 2.9 ± 0.5 3.5 ± 0.5 0.2 3.9 ± 0.4 2.2 ± 0.3 0.0008 Eting grss 22.5 ± 2.9 31.0 ± 3.7 44.3 ± 5.0 c < 0.0001 31.2 ± 3.5 34.0 ± 3.3 0.20 Stnd lert 2.0 ± 0.5 1.6 ± 0.5 1.9 ± 0.5 0.8 3.1 ± 0.5 0.6 ± 0.2 0.0001 Self-grooming 0.8 ± 0.1 0.9 ± 0.2 0.5 ± 0.2 0.3 1.1 ± 0.2 d 0.4 ± 0.1 e 0.02 Eting/licking soil/fence 0.7 ± 0.3 2.4 ± 0.6 2.7 ± 0.1 0.08 0.9 ± 0.3 d 2.98 ± 0.7 e 0.04 Numer of squres crossed 27.0 ± 2.7 36.2 ± 2.8 43.9 ± 2.7 c < 0.0001 38.3 ± 2.6 33.1 ± 2.2 0.06 Distnce trvelled (metres) 163.3 ± 272.2 ± 338.8 ± 18.4 24.2 26.4 c < 0.0001 293.8 ± 222.4 ± 24.7 d 15.8 e 0.001 The horses stood more inctive, showed higher frequency of eting/licking soil nd eting/licking wooden fence nd lower frequency of self-grooming in the period with exercise (Tle 1). Running (men ± SE % of tot os.; 0.4 ± 0.1), vigorous ply (0.2 ± 0.07), digging the ground with one front foot (0.5 ± 0.2), defection (0.4 ± 0.05), stnding sleep (0.2 ± 0.07) nd rolling on the ck (0.3 ± 0.05) were rrely oserved nd were not ffected y exercise tretment or pddock size. The recorded ehviours did not chnge over time (from week 1 to 3) within the non-exercise period, nor within the exercise period. The horses were more ctive in the lrge pddock compred to the medium nd smll pddock (Tle 1), nd they lso trvelled longer distnce. The min reson for this incresed ctivity ws tht the horses te more grss from under the fence. The horses lso stood inctive more often in the smll pddock compred to the lrger ones, ut none of the other ehviours were ffected y pddock size. There were no significnt interctions etween pddock size nd exercise tretment for ny of the ehviours. At low tempertures nd rin (wether ctegory 1), the horses were more restless, nd wlked significntly more thn in wrmer wether (wether ctegories 2, 3 nd 4) (Fig 1).
20 18 Wlking (% of oservtions) 16 14 12 10 8 6 4 2 0 5-10 C Strong wind Moderte/hevy rin 10-15 C Moderte rin 10-15 C 15-25 C Figure1. Effect of wether on wlking in individul pddocks (men + SE). Mens with different letters differ significntly,, P<0.05. Although digging the ground with one front foot generlly hd low frequency, this ehviour ws more prevlent during cold wether (P<0.05), nd the horses lso stood more lert t low tempertures (P<0.05) (Fig 2). These findings could not e explined y ny ovious disturnces in the pddock surroundings. % of oservtions 7 6 5 4 3 2 1 0 Stnding lert Digging the ground 5-10 C Strong wind Moderte/hevy rin 10-15 C Moderte rin 10-15 C 15-25 C Figure 2. Effect of wether on stnding lert nd digging the ground in individul pddocks (mens + SE). Mens within the sme ehviour rs with different letters, differ significntly,, P<0.05. On the other hnd, the horses tended to e stnding more sleep t wrm wether (ctegory 4, 0.6 ± 0.4 %) compred to wether ctegory 1 (0.0 ± 0.0), wether ctegory 2 (0.12 ± 0.07) nd wether ctegory 3 (0.08 ± 0.06) (P=0.06).
Discussion As hypothesised dily exercise significntly reduced the generl ctivity s shown y decresed time spent wlking, decresed distnce trvelled, less exploring of the environment nd less stnding lert. In comprison, Cnitz et l. (1991) found tht horses under trining were more relxed t the stles thn horses without trining nd Chy et l. (2006) found n incresed ctivity in horses turned out for only 2 h/week thn horses turned out for 12h/week. There is however, importnt to distinguish etween forced exercise (e.g. riding, pulling, nd mechnicl wlker) nd free exercise (pddock or psture). Even though oth the results from the present experiment nd Cnitz et l. (1991) suggest tht forced exercise reduce the motivtion for movement nd ctivity, it will not necessrily imply tht the horses do not hve n dditionl need for free exercise. While the present experiment found low frequency nd no significnt increse in running or vigorous ply in the non-exercise period, Chy et l. (2006) found tht horses turned out for 2 h/week were more likely to trot, cnter nd uck thn horses turned out for 12h/week. Similrly, Jensen (2001) found tht clves performed more trotting nd locomotor ply fter 3 dys of confinement compred to clves with only 1 or 0 dys in confinement. Possile explntions for the low frequency of running nd plying in our experiment my e the high ge of the horses nd tht these horses hd een t this frm for severl yers nd hence were very fmilir with oth the pddocks nd the dily ctivities. As commented y Frser (1992), ply ehviour mostly occur in young horses. Our hypothesis tht lrger pddock size would increse running nd plying ws not confirmed, ut time spent eting grss, the numer of squres crossed nd the distnce trvelled per se incresed in ddition to decresed pssive stnding when incresing the pddock size. Interestingly, the incresed ctivity in the lrger pddocks ws minly due to n incresed time spent eting grss from under the fence. The longer fence perimeter of course exposed the horses to more grss. As the horses were fed just efore turn out, the incresed ctivity ws proly not relted to nutritionl needs per se, ut rther tht grss ws n interesting stimulus. It is possile tht the effect of decresed pssive stnding could e extrpolted if incresing the pddock size further, however it is questionle whether incresed pddock size under the present conditions would entil more running nd plying (Dnish recommendtions: minimum of 800 m 2 ). During hevy rin nd strong wind the horses incresed the time spent wlking, stnding lert nd digging the ground. Both the oserved digging nd repeted wlking in the present experiment might e ehviour expressing frustrtion of the wether conditions nd imptience to get wy from it. Rugs or lnkets is often used in trditionl horse keeping nd will oviously reduce the climtic impct. However, the enefit of keeping horse in smll pddock without shelter on dys with hevy rin, eventully comined with strong wind is questionle. In conclusion, dily exercise significntly reduced the generl ctivity in the pddocks. Incresing the pddock size to 450 m 2, incresed the time spent eting grss from under the fence nd decresed the time spent stnding pssively. Acknowledgements We would like to thnk the Norwegin Equine Centre, Strum for lending us the horses nd fcilities to complete these experiments. We lso would like to thnk Dr. Inger Lise Andersen for vlule comments on this mnuscript. References my e cquired y contcting the corresponding uthor.