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Suckling behaviour of young dairy calves with their own and alien mothers
Applied Animal Behaviour Science, 33 ( 1992 ) 165-173 Elsevier Science Publishers B.V., Amsterdam
165
Suckling behaviour of young dairy calves with their own and alien mothers M. Spinka and G. Illmann Research Institute of Animal Production, CS- 104 O0 Prague 10 - Uhfin~ves, Czechoslovakia (Accepted 4 October 1991 )
ABSTRACT ,Spinka, M. and Illmann, G., 1992. Suckling behaviour of young dairy calves with their own and alien mothers. Appl. Anita. Behav. Sci., 33:165-173. Dairy cows with their calves were placed on the first day after parturition (Day 1 ) in a group of cows and calves. Each cow was removed on Day 5, after her parturition, while her calf was left in the group for a further 5 days or more so that the group contained twice as many calves as cows. The suckling behaviour was observed in order to examine the difference in the suckling of calves with and without mothers and to assess whether the cows are evenly suckled. Calves with their mothers present suckled on them almost exclusively, and did so in a "normal' opposite parallel position on 80-90% of occasions, whereas most calves with their mothers absent suckled on more than one cow, and in a normal position on only 30-47% of occasions. Suckling was organised in closely associated suckling bouts, or 'meals'. With the removal of the mother, the frequency of meals changed, but their mean duration remained stable at 7-9 min. After the mother was removed, the total time spent suckling fell from a mean of 6.0 to 2.3%, but increased during the following days. Because the suckling of alien calves was unevenly distributed among cows, the variation among the cows in the total time being suckled was very wide.
INTRODUCTION In practical dairy husbandry, calves are either isolated from their mothers immediately after birth or are allowed to suckle from the udder for 1 or 2 days only. However, there may be advantages in letting the calf suckle the dam for s e v e r a l d a y s . F i r s t , s u c k l i n g m a y b e s u p e r i o r t o t e a t f e e d i n g b y r e s u l t i n g in higher milk consumption and fewer digestive problems, leading to higher w e i g h t g a i n ( L e N e i n d r e e t al., 1 9 7 9 ; M e t z a n d M e t z , 1984; M e t z , 1 9 8 7 ) . S e c o n d l y , n a t u r a l s u c k l i n g is l e s s l a b o u r i n t e n s i v e t h a n m i l k i n g c o l o s t r u m a n d f e e d i n g it t o t h e c a l v e s . O n t h e o t h e r h a n d , t h e r e m a y b e d i s a d v a n t a g e s in leaving the calf with its mother. The welfare consequences of breaking the Correspondence to: M. Spinka, Research Institute of Animal Production, CS-104 00 Prague 10 - Uh~'infives, Czechoslovakia.
© 1992 Elsevier Science Publishers B.V. All rights reserved 0168-1591/92/$05.00
166
M. ~;PINKA AND G. ILLMANN
bond after several days of mutual contact are unknown. Also, the calf may be unable to consume the increasing quantities of milk produced (Metz, 1987 ), resulting in suppression of milk production a n d / o r occurrence of mastitis. The present study examined a potential natural suckling system of husbandry in which alien calves were joined to a group of cow-calf pairs. Suckling behaviour was observed in the group in order to examine the following questions. Are all the dams suckled sufficiently? Are the young motherless calves able to suckle alien dams? What is the difference in the suckling of own and alien calves? MATERIALS AND METHODS
Calves were born to heifers of the Bohemian Pied (Simmental) double purpose breed housed as a group in a loose stable. Each calf spent its first day of life together with its mother in the group of pregnant heifers. The day after parturition, the two were transferred to the experimental group of cows and calves. The cows were left for 4-5 days to move freely in the group without being milked, and were then transferred to another farm, while their calves were kept in the group for a further 5-16 days. Hence, the experimental group consisted of the cows, their own calves aged 1-6 days, and older alien calves. Twenty-four cows and their calves were used. Two of the 24 newborn calves were rejected by their mothers but each was adopted by cows which had calved shortly before the two were born. For the present study, these cows were considered as mothers to the two calves. The number of cows present in the experimental group varied at any one time between one and six,the number of calves between two and ten, and the calf: cow ratio between 1.2:1 and 2.5:1. The calves in the group were observed for 18 h (04:40-22:40 h) on each of 13 days in order to assess the total time of suckling of individual calves and the total time of being suckled of individual cows. The calves were also observed for 9 h ( 13:40-22:40 h) on 24 days in order to examine the age changes in suckling behaviour. Every 2 min, each calf was observed as to whether it was: ( i ) suckling (had a teat in its mouth ); (ii) attempting to suckle, by orienting its mouth towards the udder of any cow. The suckled cow was noted and three body positions of the suckling calf were distinguished: normal, with the calf standing parallel to the cow's body; from the side, the calf's body diverging from the cow's by more than 45 °; from behind, between the cow's hind legs. During the 18-h periods, 16 of the 24 calves were observed with mother present, and 13 with mother absent. Seventeen of the 24 cows were observed during at least one 18-h observation period. Data obtained from the 9-h observations were divided into seven categories according to the age of the calf. Thirteen of the 24 calves were observed on the day after birth (Day 1 ), 15 on Day 2, 10 on Day 3, and 13 on Day 4.
167
SUCKLING BEHAVIOUR OF CALVES
Twelve observations were made of calves on the afternoon after their mothers were removed, 5-6 days after parturition. The final two categories were on 12 motherless calves at Days 7-8 and eight motherless calves on Days 9-10. The temporal pattern of suckling was examined in detail by dividing suckling into 'b'~uts' and 'meals'. A bout was defined as an uninterrupted sequence of suckling records. The distribution of the intervals between successive suckling bouts over all days and all calves was analysed using logarithmic survivorship plot (Hammel et al., 1988; Sibly et al., 1990). The analysis resulted in the definition of a meal as a group of closely associated suckling bouts, and the age changes in the number and duration of meals were examined. Non-repeated analysis of variance (ANOVA) followed by Tukey's multiple range analysis (Winer, 1970) was used for testing the significance of age changes. The Mann-Whitney Utest and 2'2 test were used for non-parametric comparisons (Siegel, 1956). TABLE 1 Suckling of calves with their mothers present in the group and without them during 18-h observation periods Calves with mothers (2-6 days after birth ) (t1= 16)
Calves without mothers ( 7-16 days after birth ) ( n = 13)
No. of calves suckling 1 cow 2 cows 3 cows 4 cows
10~ 6 0 0
2b
5 4 2
Suckling on preferred cow (% of total suckling time) Median
Range
70- 100
77 d 40-100
52 16-116
54 32-88
14~ 4-26
20 I 8-48
100 c
Total time suckling (min per 18 h) Median Range
Total time suckling attempts (min per 1 8 h ) Median Range
a.bl0/16 VS. 2/ 13; significantly different; Z-"= 6.56, P < 0.02. c'dSignificantly different: M a n n - W h i t n e y U test, z = 3.298, P < 0.001. ~XSignificantly different; M a n n - W h i t n e y U test, z = 2.442, P < 0.015.
168
M. gPINKA AND G. ILLMANN
RESULTS
Suckling by the calves Ten out of 16 calves with mothers suckled on their dam only, while 11 of 13 motherless calves suckled on more than one cow (X2= 6.56, P < 0.05; Table 1 ). All 16 calves with mothers preferred to suckle on their own mother. Most motherless calves preferred to suckle one cow, and most calves had the same preferred cow. Altogether there were 14 observation periods when two or more cows and two or more alien calves were in the group. In ten of these periods, all alien calves preferred the same cow. In three periods, two different cows, and only once three different cows were preferred by different calves. The median total suckling time per 18 h was very similar for calves with and without mothers. Calves with mothers spent less time attempting to suckle (Table 1 ).
Age changes in suckling The variation in the time spent suckling over the 10 days was significant (Fig. 1; ANOVA, P = 0 . 0 0 6 ) , with a decrease in the afternoon following separation from the m o t h e r (from 6.0 to 2.3%; Tukey's test, P < 0 . 0 5 ). The apparent increase to 4.7% at the next observation was not significant. The time spent in attempts to suckle did not vary significantly with the age of the calves. When suckling on Days 1-4, the calves usually assumed the 'normal' position (Fig. 2 ). After the m o t h e r was removed, the incidence of suckling in the normal position fell to less than 50% (ANOVA, P<0.001 ). This change between Days 4 and 5-6 was the only significant one (Tukey's test, P < 0 . 0 5 ). The distribution of the lengths of non-suckling intervals between successive suckling bouts is presented in Fig. 3 in the form of a logarithmic survivorship plot. The plotted frequencies do not form a straight line. This indicates that the probability of resumption of suckling depends on the duration of the break. There were more breaks equal to or shorter than 10 min than expected. Consequently, any group of successive suckling bouts separated by pauses equal to or shorter than 10 min was considered to be a meal. The number of meals varied significantly across days (Fig. 4; ANOVA, P < 0.001 ). Tukey analysis revealed a significant decrease on the day on which the mother was removed (from 4.7 to 1.6), and a subsequent non-significant increase. Neither the time spent suckling during each meal nor the total duration of meal varied significantly with age.
Cows being suckled The total time the cows were suckled by their own calves, by alien calves, and by all calves during an 18-h period is shown in Fig. 5. Seven cows were
SUCKLINGBEHAVIOUROF CALVES
U,I
8
..................................
169
i mother i removed
] ~ - .........................................
....................................
J
I_J ,< I-
4- . . . . . .
÷ .......... 41" . . . . . . . "h
o
1-
÷
o
)
x ÷
IZ kkl 0
r¢ W
0
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
O.
1
2
3
AGE
4
5-6
IN D A Y S
7-8
POST
9-10
PARTUM
Fig. 1. The percentage o f time devoted to suckling (solid line) and suckling attempts (broken line) as dependent on age.
'~ mother z
z O -
"no L~ I,
o F7, tU L~
100
......................................i r e m o v e d
......................................................
'7
75
tU > t-
o
ill o. ¢0 i11 tr
50
25
uJ
. • ...... • .........A
_z
&::;77i • ...... 1
2
3 AGE
4
i
•
-° i 5-6
IN D A Y S
7-8
POST
9-10
PARTUM
Fig. 2. Body positions during suckling as dependent on age: normal (solid line)~ from the side (broken line), and from behind (dotted line).
hardly ever suckled by alien calves, while some were suckled by them for a long time. Consequently, the variance in the time being suckled by all calves was also large. The two cows which rejected their own calves at birth were suckled for a very short time only. DISCUSSION
Thirty-eight percent of calves with mothers cross-suckled during the 18-h period, but the cross-suckling represented, at most, 30% of the total suckling
170
M. ~ P I N K A
AND G. ILLMANN
1000-!
60
]'
>
i
I.kl I"
J
tr
]10
,~
z
/ ~S,
L r
minutes]
....-"-
.' ,2,
3001____~_ 0
12
24
INTERVALS
36
LONGER
THAN
48
60
.. M I N U T E S
Fig. 3. Logarithmic survivorship plot for the intervals between bouts of suckling.
I mother removed L
6
20
...I
< uJ
5
15 O9 .J < iii
4
+
\
+
Y
10
3 O z
"~ L9 z
2
O3 ILl
5
iz
1
0
0 1
2
3
4
5-6
AGE IN D A Y S
7-8
POST
9 -10
PARTUM
Fig. 4. Number of suckling meals (solid line) and duration of suckling per meal (broken line) as dependent on age.
time for any individual calf. A similar pattern of cross-suckling was reported both for calves during the first 6 h after birth (Edwards, 1983 ) and for calves 50 days old (Le Neindre and Garel, 1977). This indicates that young calves strongly prefer to suckle from their own mother but commonly attempt to suckle from alien adults. The orphaned calves suckled more cows. In most cases, however, all motherless calves in the group directed most of their suckling to one cow. The varied propensity of the cows to kick and butt alien calves (Broom, 1983) may play a role in the preference.
SUCKLINGBEHAVIOUROF CALVES
171
8 u)
6
a O ;Z
4 2 0 30
60
90
120
MINUTES BEING SUCKLED BY OWN CALF
8 6 < Q O Z
4-
o
I
30
II
I 60
I
90
I-I
120
MINUTES BEING SUCKLED BY ALIEN CALVES
00
o
6 4
z
2 0 30
60
90
120
MINUTES BEING SUCKLED BY ALL CALVES
Fig. 5. Duration of being suckled (during 18 h) by own, by alien calves, and by all calves for 17 cows. Hatched area denotes two cows which rejected their calves at birth.
After the dam disappeared from the group, the calves changed their suckling behaviour. They mostly adopted positions other than normal and switched suckling between more cows. The total suckling time was depressed after separation, but increased again at the next observation. Hence, young calves seem to display enough behavioural plasticity to obtain milk when they lose their dam but still remain in a group with other cows.
172
M. ~PINKA AND G. ILLMANN
An interesting finding was that the mean duration of a suckling meal remained the same whether the calves suckled their own dam or alien cow(s). Graf et al. (1989) listed numerous investigations and concluded that the duration of a meal was roughly constant in calves of different breeds and ages. The present results suggest that the meal duration is insensitive even to profound changes in the social environment. The cows in the group were suckled to a widely varying extent. Two of 17 cows were suckled less than 20 min per 18 h, and seven were suckled almost only by their own calves. Additional calves in a group of cow-calf pairs probably cannot guarantee that the milk production of each cow is removed by suckling. The dams which reject their calves post-partum might be particularly endangered by not being suckled enough.
ACKNOWLEDGEMENTS
The authors wish to thank Drs. S.A. Edwards, P. Le Neindre, J.H.M. Metz, H.H. Sambraus and two reviewers for their valuable comments on an earlier draft of this paper.
REFERENCES
Broom, D.M., 1983. Cow-calf and sow-piglet behaviour in relation to colostrum ingestion. Ann. Rech. Vet., 14: 342-348. Edwards, S.A., 1983. The behavior of dairy cows and their newborn calves in individual or group housing. Appl. Anim. Ethol., 10: 191-198. Graf, B., Verhagen, N. and Sambraus, H.H., 1989. Reduzierung des Erszatzsaugens bei kiinstlich aufgezogenen K~ilbern durch Fixierung nach dem Tr~inken oder Verl~ingerung der Saugzeit. Z/ichtungskunde, 61: 384-400. Hammel, K.L, Metz, J.H.M. and Mekking, P., 1988. Sucking behaviour of dairy calves fed milk ad libitum by bucket or teat. Anim. Appl. Behav. Sci., 20: 275-285. Le Neindre, P. and Garel, J.P., 1977. 12tude des relations mbre-jeune chez les bovins domestiques: Comparaison des liaisons entre la m~re et des veaux 16gitimes ou adopt6s. Biol. Behav., 2: 39-49. Le Neindre, P., Menard, M.F. and Garel, J.P., 1979. Suckling and drinking behaviour of newborn calves of beef or dairy cows. Ann. Rech. Vet., 10:211-212. Metz, J., 1987. Productivity aspects of keeping dairy cow and calf together in the post-partum period. Livest. Prod. Sci., 16: 385-394. Metz, J. and Metz, J.H.M., 1985. Die Bedeutung der Mutter in der Umwelt des neugeborenen Kalbes. KTBL-Schrift, 307:188-197.
SUCKLING BEHAVIOUR OF CALVES
173
Sibly, R.M., Nott, H.M.R. and Fletcher, D.J., 1990. Splitting behaviour into bouts. Anim. Behav., 39: 63-69. Siegel, S., 1956. Nonparametric Statistics for the Behavioral Sciences. McGraw-Hill, New York. Winer, B.J., 1970. Statistical Principles in Experimental Design. McGraw-Hill, London.
165
Suckling behaviour of young dairy calves with their own and alien mothers M. Spinka and G. Illmann Research Institute of Animal Production, CS- 104 O0 Prague 10 - Uhfin~ves, Czechoslovakia (Accepted 4 October 1991 )
ABSTRACT ,Spinka, M. and Illmann, G., 1992. Suckling behaviour of young dairy calves with their own and alien mothers. Appl. Anita. Behav. Sci., 33:165-173. Dairy cows with their calves were placed on the first day after parturition (Day 1 ) in a group of cows and calves. Each cow was removed on Day 5, after her parturition, while her calf was left in the group for a further 5 days or more so that the group contained twice as many calves as cows. The suckling behaviour was observed in order to examine the difference in the suckling of calves with and without mothers and to assess whether the cows are evenly suckled. Calves with their mothers present suckled on them almost exclusively, and did so in a "normal' opposite parallel position on 80-90% of occasions, whereas most calves with their mothers absent suckled on more than one cow, and in a normal position on only 30-47% of occasions. Suckling was organised in closely associated suckling bouts, or 'meals'. With the removal of the mother, the frequency of meals changed, but their mean duration remained stable at 7-9 min. After the mother was removed, the total time spent suckling fell from a mean of 6.0 to 2.3%, but increased during the following days. Because the suckling of alien calves was unevenly distributed among cows, the variation among the cows in the total time being suckled was very wide.
INTRODUCTION In practical dairy husbandry, calves are either isolated from their mothers immediately after birth or are allowed to suckle from the udder for 1 or 2 days only. However, there may be advantages in letting the calf suckle the dam for s e v e r a l d a y s . F i r s t , s u c k l i n g m a y b e s u p e r i o r t o t e a t f e e d i n g b y r e s u l t i n g in higher milk consumption and fewer digestive problems, leading to higher w e i g h t g a i n ( L e N e i n d r e e t al., 1 9 7 9 ; M e t z a n d M e t z , 1984; M e t z , 1 9 8 7 ) . S e c o n d l y , n a t u r a l s u c k l i n g is l e s s l a b o u r i n t e n s i v e t h a n m i l k i n g c o l o s t r u m a n d f e e d i n g it t o t h e c a l v e s . O n t h e o t h e r h a n d , t h e r e m a y b e d i s a d v a n t a g e s in leaving the calf with its mother. The welfare consequences of breaking the Correspondence to: M. Spinka, Research Institute of Animal Production, CS-104 00 Prague 10 - Uh~'infives, Czechoslovakia.
© 1992 Elsevier Science Publishers B.V. All rights reserved 0168-1591/92/$05.00
166
M. ~;PINKA AND G. ILLMANN
bond after several days of mutual contact are unknown. Also, the calf may be unable to consume the increasing quantities of milk produced (Metz, 1987 ), resulting in suppression of milk production a n d / o r occurrence of mastitis. The present study examined a potential natural suckling system of husbandry in which alien calves were joined to a group of cow-calf pairs. Suckling behaviour was observed in the group in order to examine the following questions. Are all the dams suckled sufficiently? Are the young motherless calves able to suckle alien dams? What is the difference in the suckling of own and alien calves? MATERIALS AND METHODS
Calves were born to heifers of the Bohemian Pied (Simmental) double purpose breed housed as a group in a loose stable. Each calf spent its first day of life together with its mother in the group of pregnant heifers. The day after parturition, the two were transferred to the experimental group of cows and calves. The cows were left for 4-5 days to move freely in the group without being milked, and were then transferred to another farm, while their calves were kept in the group for a further 5-16 days. Hence, the experimental group consisted of the cows, their own calves aged 1-6 days, and older alien calves. Twenty-four cows and their calves were used. Two of the 24 newborn calves were rejected by their mothers but each was adopted by cows which had calved shortly before the two were born. For the present study, these cows were considered as mothers to the two calves. The number of cows present in the experimental group varied at any one time between one and six,the number of calves between two and ten, and the calf: cow ratio between 1.2:1 and 2.5:1. The calves in the group were observed for 18 h (04:40-22:40 h) on each of 13 days in order to assess the total time of suckling of individual calves and the total time of being suckled of individual cows. The calves were also observed for 9 h ( 13:40-22:40 h) on 24 days in order to examine the age changes in suckling behaviour. Every 2 min, each calf was observed as to whether it was: ( i ) suckling (had a teat in its mouth ); (ii) attempting to suckle, by orienting its mouth towards the udder of any cow. The suckled cow was noted and three body positions of the suckling calf were distinguished: normal, with the calf standing parallel to the cow's body; from the side, the calf's body diverging from the cow's by more than 45 °; from behind, between the cow's hind legs. During the 18-h periods, 16 of the 24 calves were observed with mother present, and 13 with mother absent. Seventeen of the 24 cows were observed during at least one 18-h observation period. Data obtained from the 9-h observations were divided into seven categories according to the age of the calf. Thirteen of the 24 calves were observed on the day after birth (Day 1 ), 15 on Day 2, 10 on Day 3, and 13 on Day 4.
167
SUCKLING BEHAVIOUR OF CALVES
Twelve observations were made of calves on the afternoon after their mothers were removed, 5-6 days after parturition. The final two categories were on 12 motherless calves at Days 7-8 and eight motherless calves on Days 9-10. The temporal pattern of suckling was examined in detail by dividing suckling into 'b'~uts' and 'meals'. A bout was defined as an uninterrupted sequence of suckling records. The distribution of the intervals between successive suckling bouts over all days and all calves was analysed using logarithmic survivorship plot (Hammel et al., 1988; Sibly et al., 1990). The analysis resulted in the definition of a meal as a group of closely associated suckling bouts, and the age changes in the number and duration of meals were examined. Non-repeated analysis of variance (ANOVA) followed by Tukey's multiple range analysis (Winer, 1970) was used for testing the significance of age changes. The Mann-Whitney Utest and 2'2 test were used for non-parametric comparisons (Siegel, 1956). TABLE 1 Suckling of calves with their mothers present in the group and without them during 18-h observation periods Calves with mothers (2-6 days after birth ) (t1= 16)
Calves without mothers ( 7-16 days after birth ) ( n = 13)
No. of calves suckling 1 cow 2 cows 3 cows 4 cows
10~ 6 0 0
2b
5 4 2
Suckling on preferred cow (% of total suckling time) Median
Range
70- 100
77 d 40-100
52 16-116
54 32-88
14~ 4-26
20 I 8-48
100 c
Total time suckling (min per 18 h) Median Range
Total time suckling attempts (min per 1 8 h ) Median Range
a.bl0/16 VS. 2/ 13; significantly different; Z-"= 6.56, P < 0.02. c'dSignificantly different: M a n n - W h i t n e y U test, z = 3.298, P < 0.001. ~XSignificantly different; M a n n - W h i t n e y U test, z = 2.442, P < 0.015.
168
M. gPINKA AND G. ILLMANN
RESULTS
Suckling by the calves Ten out of 16 calves with mothers suckled on their dam only, while 11 of 13 motherless calves suckled on more than one cow (X2= 6.56, P < 0.05; Table 1 ). All 16 calves with mothers preferred to suckle on their own mother. Most motherless calves preferred to suckle one cow, and most calves had the same preferred cow. Altogether there were 14 observation periods when two or more cows and two or more alien calves were in the group. In ten of these periods, all alien calves preferred the same cow. In three periods, two different cows, and only once three different cows were preferred by different calves. The median total suckling time per 18 h was very similar for calves with and without mothers. Calves with mothers spent less time attempting to suckle (Table 1 ).
Age changes in suckling The variation in the time spent suckling over the 10 days was significant (Fig. 1; ANOVA, P = 0 . 0 0 6 ) , with a decrease in the afternoon following separation from the m o t h e r (from 6.0 to 2.3%; Tukey's test, P < 0 . 0 5 ). The apparent increase to 4.7% at the next observation was not significant. The time spent in attempts to suckle did not vary significantly with the age of the calves. When suckling on Days 1-4, the calves usually assumed the 'normal' position (Fig. 2 ). After the m o t h e r was removed, the incidence of suckling in the normal position fell to less than 50% (ANOVA, P<0.001 ). This change between Days 4 and 5-6 was the only significant one (Tukey's test, P < 0 . 0 5 ). The distribution of the lengths of non-suckling intervals between successive suckling bouts is presented in Fig. 3 in the form of a logarithmic survivorship plot. The plotted frequencies do not form a straight line. This indicates that the probability of resumption of suckling depends on the duration of the break. There were more breaks equal to or shorter than 10 min than expected. Consequently, any group of successive suckling bouts separated by pauses equal to or shorter than 10 min was considered to be a meal. The number of meals varied significantly across days (Fig. 4; ANOVA, P < 0.001 ). Tukey analysis revealed a significant decrease on the day on which the mother was removed (from 4.7 to 1.6), and a subsequent non-significant increase. Neither the time spent suckling during each meal nor the total duration of meal varied significantly with age.
Cows being suckled The total time the cows were suckled by their own calves, by alien calves, and by all calves during an 18-h period is shown in Fig. 5. Seven cows were
SUCKLINGBEHAVIOUROF CALVES
U,I
8
..................................
169
i mother i removed
] ~ - .........................................
....................................
J
I_J ,< I-
4- . . . . . .
÷ .......... 41" . . . . . . . "h
o
1-
÷
o
)
x ÷
IZ kkl 0
r¢ W
0
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
O.
1
2
3
AGE
4
5-6
IN D A Y S
7-8
POST
9-10
PARTUM
Fig. 1. The percentage o f time devoted to suckling (solid line) and suckling attempts (broken line) as dependent on age.
'~ mother z
z O -
"no L~ I,
o F7, tU L~
100
......................................i r e m o v e d
......................................................
'7
75
tU > t-
o
ill o. ¢0 i11 tr
50
25
uJ
. • ...... • .........A
_z
&::;77i • ...... 1
2
3 AGE
4
i
•
-° i 5-6
IN D A Y S
7-8
POST
9-10
PARTUM
Fig. 2. Body positions during suckling as dependent on age: normal (solid line)~ from the side (broken line), and from behind (dotted line).
hardly ever suckled by alien calves, while some were suckled by them for a long time. Consequently, the variance in the time being suckled by all calves was also large. The two cows which rejected their own calves at birth were suckled for a very short time only. DISCUSSION
Thirty-eight percent of calves with mothers cross-suckled during the 18-h period, but the cross-suckling represented, at most, 30% of the total suckling
170
M. ~ P I N K A
AND G. ILLMANN
1000-!
60
]'
>
i
I.kl I"
J
tr
]10
,~
z
/ ~S,
L r
minutes]
....-"-
.' ,2,
3001____~_ 0
12
24
INTERVALS
36
LONGER
THAN
48
60
.. M I N U T E S
Fig. 3. Logarithmic survivorship plot for the intervals between bouts of suckling.
I mother removed L
6
20
...I
< uJ
5
15 O9 .J < iii
4
+
\
+
Y
10
3 O z
"~ L9 z
2
O3 ILl
5
iz
1
0
0 1
2
3
4
5-6
AGE IN D A Y S
7-8
POST
9 -10
PARTUM
Fig. 4. Number of suckling meals (solid line) and duration of suckling per meal (broken line) as dependent on age.
time for any individual calf. A similar pattern of cross-suckling was reported both for calves during the first 6 h after birth (Edwards, 1983 ) and for calves 50 days old (Le Neindre and Garel, 1977). This indicates that young calves strongly prefer to suckle from their own mother but commonly attempt to suckle from alien adults. The orphaned calves suckled more cows. In most cases, however, all motherless calves in the group directed most of their suckling to one cow. The varied propensity of the cows to kick and butt alien calves (Broom, 1983) may play a role in the preference.
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8 u)
6
a O ;Z
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MINUTES BEING SUCKLED BY OWN CALF
8 6 < Q O Z
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o
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II
I 60
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MINUTES BEING SUCKLED BY ALIEN CALVES
00
o
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z
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MINUTES BEING SUCKLED BY ALL CALVES
Fig. 5. Duration of being suckled (during 18 h) by own, by alien calves, and by all calves for 17 cows. Hatched area denotes two cows which rejected their calves at birth.
After the dam disappeared from the group, the calves changed their suckling behaviour. They mostly adopted positions other than normal and switched suckling between more cows. The total suckling time was depressed after separation, but increased again at the next observation. Hence, young calves seem to display enough behavioural plasticity to obtain milk when they lose their dam but still remain in a group with other cows.
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M. ~PINKA AND G. ILLMANN
An interesting finding was that the mean duration of a suckling meal remained the same whether the calves suckled their own dam or alien cow(s). Graf et al. (1989) listed numerous investigations and concluded that the duration of a meal was roughly constant in calves of different breeds and ages. The present results suggest that the meal duration is insensitive even to profound changes in the social environment. The cows in the group were suckled to a widely varying extent. Two of 17 cows were suckled less than 20 min per 18 h, and seven were suckled almost only by their own calves. Additional calves in a group of cow-calf pairs probably cannot guarantee that the milk production of each cow is removed by suckling. The dams which reject their calves post-partum might be particularly endangered by not being suckled enough.
ACKNOWLEDGEMENTS
The authors wish to thank Drs. S.A. Edwards, P. Le Neindre, J.H.M. Metz, H.H. Sambraus and two reviewers for their valuable comments on an earlier draft of this paper.
REFERENCES
Broom, D.M., 1983. Cow-calf and sow-piglet behaviour in relation to colostrum ingestion. Ann. Rech. Vet., 14: 342-348. Edwards, S.A., 1983. The behavior of dairy cows and their newborn calves in individual or group housing. Appl. Anim. Ethol., 10: 191-198. Graf, B., Verhagen, N. and Sambraus, H.H., 1989. Reduzierung des Erszatzsaugens bei kiinstlich aufgezogenen K~ilbern durch Fixierung nach dem Tr~inken oder Verl~ingerung der Saugzeit. Z/ichtungskunde, 61: 384-400. Hammel, K.L, Metz, J.H.M. and Mekking, P., 1988. Sucking behaviour of dairy calves fed milk ad libitum by bucket or teat. Anim. Appl. Behav. Sci., 20: 275-285. Le Neindre, P. and Garel, J.P., 1977. 12tude des relations mbre-jeune chez les bovins domestiques: Comparaison des liaisons entre la m~re et des veaux 16gitimes ou adopt6s. Biol. Behav., 2: 39-49. Le Neindre, P., Menard, M.F. and Garel, J.P., 1979. Suckling and drinking behaviour of newborn calves of beef or dairy cows. Ann. Rech. Vet., 10:211-212. Metz, J., 1987. Productivity aspects of keeping dairy cow and calf together in the post-partum period. Livest. Prod. Sci., 16: 385-394. Metz, J. and Metz, J.H.M., 1985. Die Bedeutung der Mutter in der Umwelt des neugeborenen Kalbes. KTBL-Schrift, 307:188-197.
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Sibly, R.M., Nott, H.M.R. and Fletcher, D.J., 1990. Splitting behaviour into bouts. Anim. Behav., 39: 63-69. Siegel, S., 1956. Nonparametric Statistics for the Behavioral Sciences. McGraw-Hill, New York. Winer, B.J., 1970. Statistical Principles in Experimental Design. McGraw-Hill, London.