21112005
Agonistic behaviour in stable and unstable socialgroups of pregnant goats and its consequences for
kid survival and development
Andersen, I. L., Roussel, S., Ropstad, E., Braastad, B. O., Steinheim, G., Janczak, A., Jørgensen, G. M. and Bøe, K. E.
Agonistic behaviour in stable and unstable groups of goats -
consequences for kid survival and development
2
NO
RW
EGIAN
UN
IVERSITY OF LIFE SCIEN
CES
www.umb.no
Background
Female mountain goats, the ancestor of our domestic goat, live in a rigid and rocky terrain with scarce food resources and where a high competitive ability is an advantage
Female goats interact aggressively much more frequently than other female ungulates (Fournier and Festa-Bianchet, 1995)
Kaiser and Sachser (2005): in evolutionary terms mothers should try to maximise fitness by adjusting the phenotype of their offspring to the environment in which they live (“environment-adaptation hypothesis”), and under wild conditions offspring may become more offensive/competitive in high density populations (guinea pigs: e.g. Asher et al., 2004)
This is of particular relevance for farm animals since high-density, unstable social environments are the norm in our production environments
Consequences of social instability have been intensively studied in most farm animal species, but not in goats
Agonistic behaviour in stable and unstable groups of goats -
consequences for kid survival and development
3
NO
RW
EGIAN
UN
IVERSITY OF LIFE SCIEN
CES
www.umb.no
Aim
To study the effects of social instability (regrouping) during seven weeks of pregnancy on aggression, cortisolconcentrations and growth in the adult goats, and itsconsequences for survival, growth and some aspects ofbehavioural development in the kids
Agonistic behaviour in stable and unstable groups of goats -
consequences for kid survival and development
4
NO
RW
EGIAN
UN
IVERSITY OF LIFE SCIEN
CES
www.umb.no
We predicted that social instability would:
Adult goats:
– Induce higher aggression levels, especially shortly after regrouping
– Increase cortisol concentration and reduce growth
Kids:
– Produce kids with an offensive behaviour (i.e. active exploration of novel stimuli, actively trying escape when being isolated from their group)
Agonistic behaviour in stable and unstable groups of goats -
consequences for kid survival and development
5
NO
RW
EGIAN
UN
IVERSITY OF LIFE SCIEN
CES
www.umb.no
Material and methods
32 healthy , pregnant, dairy goats were distributed on 8 groups with four goats in each group:
Treatments:
– Stable groups: 4 of the groups were allowed to remain in the same group throughout the entire pregnancy
– Unstable groups: another 4 groups were subjected to pair wise regrouping every Monday for seven weeks starting six weeks of gestation
– The rotation scheme resulted in each pair in the unstable treatment having to meet two new pairs of goats and to change pen each week
Agonistic behaviour in stable and unstable groups of goats -
consequences for kid survival and development
6
NO
RW
EGIAN
UN
IVERSITY OF LIFE SCIEN
CES
www.umb.no
Materials and methods cont.
The goats were weighed 2 days prior to the start of the experimentand immediately after the seventh week of regrouping at the start and the end of the experiment
The goat kids were weighed at birth and weaning (six weeks)
The no. of live born kids, the number of each sex and kid survival wererecorded for all litters
Blood samples were drawn from the adult goats at 0830 h everyTuesday and Thursday from one week before the start ofrotation/regrouping and until one week before expected birth
Blood samples were collected from the kids at the age of three weeksfrom a maximum of two kids from each litter (a total of 50 kids)– Cortisol concentration was then analysed
Agonistic behaviour in stable and unstable groups of goats -
consequences for kid survival and development
7
NO
RW
EGIAN
UN
IVERSITY OF LIFE SCIEN
CES
www.umb.no
Materials and methods cont.
Behavioural tests in the home pens:
The social test at the age of1 and 7 weeks
The novel object test at the age of 5 weeks
Agonistic behaviour in stable and unstable groups of goats -
consequences for kid survival and development
8
NO
RW
EGIAN
UN
IVERSITY OF LIFE SCIEN
CES
www.umb.no
Results
Butting/clashing (no. of interactions)
0
5
10
15
20
25
30
35
Week 1, day 1Week 1, day 5Week 2, day 1Week 2, day 5Week 4, day 1Week 4, day 5Week 7, day 1Week 7, day 5
2 w. bef. birth, day 1
2 w. bef. birth, day 5
Unstable groupsStable groups
Agonistic behaviour in stable and unstable groups of goats -
consequences for kid survival and development
9
NO
RW
EGIAN
UN
IVERSITY OF LIFE SCIEN
CES
www.umb.no
Results cont.
0
2
4
6
8
10
12
Week 0, day 2Week 0, day 4Week 1, day 2Week 1, day 4Week 4, day 2Week 4, day 4Week 7, day 2Week 7, day 4
2 weeks bef. birth, day 2
2 weeks bef. birth, day 4
Last week bef. birth, day 2
Last week bef. birth, day 4
Cor
tisol
(ng/
litrUnstable groups
Stable groups
Agonistic behaviour in stable and unstable groups of goats -
consequences for kid survival and development
10
NO
RW
EGIAN
UN
IVERSITY OF LIFE SCIEN
CES
www.umb.no
Results cont.
No. sign. effects of treatment or age on growth or kid production of the goats
Goats with a high mean level of cortisol throughout theexperimental period, gave birth to significantly fewer kids (R=-0.5, P < 0.01)
Agonistic behaviour in stable and unstable groups of goats -
consequences for kid survival and development
11
NO
RW
EGIAN
UN
IVERSITY OF LIFE SCIEN
CES
www.umb.no
Unstable groups
0
2
4
6
8
10
12
14
16
0 to10 11 to 30 31 to 50 51 to 70 71 to 90 >100
No of fights involving butting/clashing
No.
of g
oats
Stable groups
0
2
4
6
8
10
12
14
16
0 to10 11 to 30 31 to 50 51 to 70 71 to 90 >100
No. of fights involving butting/clashing
No.
of g
oats
Extremely aggressive and non-aggressive goats
0,0
0,5
1,0
1,5
2,0
2,5
3,0
3,5
4,0
No. of kids Birth weight
< 20 fights
>70 fightsSign. differencesbetween extremes!
Agonistic behaviour in stable and unstable groups of goats -
consequences for kid survival and development
12
NO
RW
EGIAN
UN
IVERSITY OF LIFE SCIEN
CES
www.umb.no
Results cont.
Basal cortisol level in the goat kids (ng/ml)
a
b
0
1
2
3
4
5
6
7
8
9
10
Kids from unstable groups Kids from stable groups
Agonistic behaviour in stable and unstable groups of goats -
consequences for kid survival and development
13
NO
RW
EGIAN
UN
IVERSITY OF LIFE SCIEN
CES
www.umb.no
Results from the behaviouraltests
No. of nose contacts with stimulus cage/kids in the second social test
a
b
8
9
10
11
12
13
14
15
16
Kids from unstable groups Kids from stable groups
No. of escape attempts in the first and second social test
a
b
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
Kids from unstable groups Kids from stable groups
First social testSecond social test
Kids from the unstablegroups tended to spend more time in contact withthe novel object (P = 0.09)
Conclusions
Except for the higher aggression level in the unstable groups, social instability did not have any other significant effects onfactors such as growth, cortisol level or kid production in the goats
There were only minor effects on the behavioural development in the goat kids. However, some of the results suggested a more active coping style in the kids from goats belonging to the unstable groups
