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A unambiguous relationship between weight of animal, index of dominance and DFC [Tab. 1] was found in the first investigation. The heaviest animal occupied the highest rank and showed the highest DFC for activity and feeding. Its DFC suggests that there was no indication of stress on this individ-ual. Animal No. 4 had the lowest weight and lowest rank in the hierarchy. During daily conflicts, this animal was most frequently attacked by others and was prevented from grazing, ruminating or resting.

These social interactions resulted in extremely low DFC. Social stress caused by other animals led to complete desynchronisation between feeding and circadian zeitgebers.

In the second investigation, the main structure of measured activity showed high similarity between the two different measuring systems (BERGER et al. 1997) and decreasing DFCs during periods of stress of different origin [Fig. 2]. After short immobilisation of the animal, the DFC dropped to a low level and was only slowly re-established. Low DFCs were observed also during two phases in No-vember, when other animals were captured after hunting in the enclosure.

Control group Experimental group

1. phase: 5 animals 10 animals

2. phase: 5 animals 15 animals 5 animals

5 animals

3. phase: 5 animals 15 animals 5 animals

5 animals

4. phase: 5 animals 20 animals 5 animals

In the third investigation, a significant difference of DFC (feeding) between the experimental and control groups was found to exist only in the first phase [Tab. 2]. No such significant differences were revealed in any of the other phases. Accordingly, we could not affirm social stress from social insta-bility and rising group size. Comparison between phases showed significant changes in either group [Tab. 3]. DFCs in either group were clearly decreased in the third phase compared to the other three phases [Tab. 4]. A stress reaction, consequently, was established only in the third phase. This was certainly due to exterior disturbance (mowing operations in a neighbouring enclosure).

Tab. 1 Weight, index of dominance and DFC in the group of four hinds (first investigation).

Tab. 5 shows means, standard deviations and range of cortisol metabolite levels measured on days 3 and 10 in each phase. A significant difference between experimental and control groups could be found only in the third phase [Tab. 2]. This primarily was due to elevation of metabolite concentra-tions on day 10, after exchange of five individuals, and thus may not have reflected an effect of in-creased social instability. A stress-related increase in adrenal activity should occur immediately after introduction of new animals and should lead to elevation in faecal cortisol metabolites within 24 hours, as was recently demonstrated for roe deer (DEHNHARD pers. comm.). Our sampling regime on days 3 and 10 of each phase may have been unsuitable for identification of treatment-dependent changes of adrenal activity.

Fig. 2 DFCs (activity) of one hind from April 1995 to January 1996 (second investigation), periods of stress by human interference are indicated.

Comparison between phases showed significant changes for cortisol metabolites in either group [Tab.

3]. This was due to higher cortisol metabolite levels in phase three and may have resulted from exter-nal disturbance reported rather than from treatment.

Animal Weight Index of DFC [%]

[kg] dominance* Activity Feeding

red deer 1 118.88 1 88.06 100.0

red deer 2 115.4 -0.19 / /

red deer 3 111.87 -0.2 61.20 66.3

red deer 4 99.4 -1 55.86 0.0

* Index of dominance = (victories - defeats) / (victories + defeats)

0 20 40 60 80 100

Apr Apr May May May Jun Jun Jul Aug Aug Aug Sep Sep Sep Oct Oct Nov Nov Nov Dec Dec Dec Jan

Month

DFC Activity [%]

stress period 1:

immobilisation

stress period 2:

hunting

stress period 3:

hunting standard-deviation

standard-deviation

Tab. 2 Comparison between control and experimental groups (variance analysis) in the third experiment.

Tab. 3 Comparison between phases (variance analysis) in the third experiment.

Tab. 4 DFCs of activity and feeding for each animal in different phases (third experiment).

Despite the small number of data, the results revealed certain trends. We obtained a negative relation-ship between DFC (of activity or feeding) and cortisol metabolite levels and a positive relationrelation-ship between daily totals (of activity and feeding) and cortisol metabolite levels. Among behavioural pa-rameters, rising vigilance indicated rising stress, and a high rank in social hierarchy sometimes was related to stress. We think, that the need to defend their high rank quite frequently may have contrib-uted to this result. In comparison with the index of dominance, vigilance appears to be the best indi-cator of stress.

Cortisol DFC Activity DFC Feeding

1. Phase / / *

2. Phase / / /

3. Phase * / /

4. Phase / / /

* significant different between control and experimental group

Cortisol DFC Activity DFC Feeding

Experimental group * * *

Control group * * *

* significant different between phases

DFC Activity [%]

Phases Control group Experimental group

1 2 3 4 5 Mean 1 2 3 4 5 6 7 8 9 10 Mean

1 95 100 93 100 100 97.7 100 100 100 100 100 82 100 100 100 90 97.2

2 82 85 66 90 86 81.6 100 100 100 95 92 74 100 92 95 94.2

3 73 71 76 65 71 71.3 72 60 68 55 64 66 63 64 68 64.5

4 89 82 100 100 100 94 78 79 93 92 86 100 87 88 94 88.4

DFC Feeding [%]

Phases Control group Experimental group

1 2 3 4 5 Mean 1 2 3 4 5 6 7 8 9 10 Mean

1 94 100 92 86 100 94.3 0 100 63 100 84 70 100 100 100 86 80.3

2 83 94 92 100 100 93.9 100 100 86 100 95 90 73 100 86 100 92.9

3 73 100 71 64 91 79.7 61 44 55 61 78 68 77 53 58 67 62.2

4 93 100 100 100 100 98.5 87 84 86 86 86 86 100 100 86 82 88.3

Tab. 5 Mean, standard deviation and range of cortisol metabolite levels in control and experimental groups for different acts of sampling (third experiment).

Fig. 3 summarises data obtained by correlating cortisol metabolite levels and behavioural parameters. Trends and significant correlations between cortisol metabolite level and behavioural parameters (third experiment).

CONCLUSION

A time structure of behavioural parameters which are in harmony with the circadian zeitgeber is char-acteristic of normal conditions. This clear rhythmic pattern of activity and feeding was disturbed dur-ing different stress periods. Therefore, analysdur-ing of time structure of long-term and continuously measured activity and feeding proved to be a useful method to detect stressful conditions. In case of cortisol metabolite levels in faeces, no significant effect could be related to the treatments. This might be attributable to an inadequate sampling regime on days 3 and 10 after treatment. Further investiga-tions therefore should be carried out considering data from roe deer which showed increase of cortisol metabolites in faeces within 24 hours after application of stress.

(-) (-) (+) (+)

(+) (+)

0 3 6 9 12 15

number of animals

trend (direction) significance DFC activity

DFC feeding

total activity

total feedingvigilance index of dominance number of data sets per animal: 2 to 8

Cortisol metabolite level [ng/g]

Phases Day Control group Experimental group

mean standard dev. minimum maximum mean standard dev. minimum maximum

1 3 11.3 7.5 3.1 24.6 30.1 18.9 10.5 79.9

10 15.4 14.1 4.7 43.3 16.4 11.6 5.7 45.9

2 3 33.4 32.2 4.7 87.9 39 42.0 5.3 140

10 24.5 4.1 18.5 29.7 16.9 14.9 3.4 53.1

3 3 21.3 5.5 12.7 29.6 29.4 12.7 11 46.6

10 36 11.4 20.2 55.5 60.5 37.7 9.6 144

4 3 25.4 11.3 14.7 39.6 24.9 14.2 11 56.9

10 39.9 14.3 20 60.7 36.8 19.9 11.3 76.3

REFERENCES

BERGER, A.; SCHOBER, F.; SCHEIBE, K.-M.; REIMOSER,S.; EICHHORN, K. (1997): Comparison of two telemetric methods for measuring behavioural parameters. International Journal of Mammalian Biology, Z. Säugetierkd. 62 (II), 14-17.

PALME, R.; MÖSTL, E. (1997): Measurement of cortisol metabolites in faeces of sheep as a parameter of cortisol concentration in blood. Z. Säugetierkunde, 62, (II), 192-197.

SCHEIBE, K.-M.; SINZ, R.; TEMBROCK, G. (1978): Biorhythmische Verfahren und Ergebnisse zur Belastungsdiagnostik in der Tierproduktion. In: LYHS, L., Umwelt und Leistung landwirtschaftlicher Nutztiere, (in German), pp. 61-69.

SCHEIBE, K.-M.; SCHLEUSNER, T.; BERGER, A.; EICHHORN, K.; LANGBEIN, J.; DAL ZOTTO, L.; STREICH, W.J. (1998):

ETHOSYS® - new system for recording and analysis of behaviour of free-ranging domestic animals and wildlife. Appl. Anim.

Behav. Sci. 55, 195-211.

SCHEIBE, K.-M.; BERGER, A.; LANGBEIN, J.; STREICH, W.J.; EICHHORN, K. in press.: Comparative Analysis of ultradian and circadian behavioural rhythms for diagnosis of biorhythmic state of animals. Biol. Rhythm. Res.

SCHOBER, F.; FLUCH, G. (1995): Heart rate and body temperature repeater telemetry system for wildlife animals. In: Biote-lemetry XIII, Proc. 13th Int. Symp. BioteBiote-lemetry. Ed. by C. CRISTALLI; C.J.JR. AMLANER; M.R. NEUMAN. Williamsburg, Virginia, U.S.A., 366-371.