www.elsevier.comrlocaterapplanim
The effect of omitted milking on the behaviour of
cows in the context of cluster attachment failure
during automatic milking
J. Stefanowska
a,), M. Plavsic
b, A.H. Ipema
a,
M.M.W.B. Hendriks
aa ( )
Institute of Agricultural and EnÕironmental Engineering IMAG-DLO , Mansholtlaan 10-12, P.O. Box 43,
6700 AA Wageningen, Netherlands
b
LiÕestock Research Institute, 21000 NoÕi Sad, YugoslaÕia
Accepted 7 December 1999
Abstract
In robotic milking there is always a slight chance of failure to attach the milking cluster. Attachment failure is most likely for cows whose udder conformation is less convenient for robot attachment. In general, after milking failure cows try to revisit the milking robot if they are not sent to a separate area. Since it is difficult to estimate the effect of milking failure on such a cow and her welfare in conditions of robotic milking, a specific 16-day trial was conducted on 12 cows. These cows were milked in a milking parlour with six milking stalls. Each afternoon milking, three cows were not milked. All the cows were closely observed in the cubicle house for 1 h after the afternoon milking. Thereafter, all cows were brought to the milking parlour the third time and the three unmilked cows were milked. In total, each cow was observed 12 times after milking and four times after omitted milking. The following behavioural traits were registered: time budget for the 1 h, occurrence and time until eating, drinking, lying, urination and defecation, and aggressive interactions. Milking order was defined on the basis of how often a cow came to the milking parlour in the first batch of six cows. Moreover, the data related to the milk yield and the use of the automatic feeding installation with the complete diet were analysed. After omitted
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milking, only the cows from the first batch stood longer in cubicles 14.2 min of 1 h and lay less Ž5.4 min of 1 h than milked cows of the same batch respectively 7.0 min and 16.3 min for. Ž
. Ž .
standing and lying in cubicles P-0.01 . After omitted milking, cows urinated earlier and more
Ž . Ž . Ž . Ž .
frequently 64.5% than milked cows 36.3% P-0.002 both batches . There were no
)Corresponding author. Tel.:q31-747-6450; fax:q31-3174-25670.
Ž .
E-mail address: j.stefanowska@imag.dlo.nl J. Stefanowska .
0168-1591r00r$ - see front matterq2000 Elsevier Science B.V. All rights reserved. Ž .
statistically significant differences in eating time and feed intake after milking and omitted
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milking. Milk yield per cow averaged 24.9 kg during days with omitted delayed by 1 h milking
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and 25.3 kg during the days without omitted milking P-0.05 . It was concluded that cows show
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some signs of discomfort after omitted milking urination ; this discomfort seemed to be greater in
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cows coming earlier to the milking parlour afterwards they preferred to stand rather than to lie . The 60% of cases of milk leakage found after omitted milking indicates that failed cluster attachment can be accompanied by an extra risk factor for the occurrence of mastitis. However, omitted milking as a treatment did not influence feeding and aggressive behaviour or milking order when unmilked cows were brought to the milking parlour the third time together with the milked cows. Our methods and results can be useful for estimating the effects of robot milking failures on a cow. Future studies should pay particular attention to high-yielding cows and to longer periods of delayed milking.q2000 Elsevier Science B.V. All rights reserved.
Keywords: Omitted milking; Cluster attachment failure; Milk leakage; Automatic milking; Dairy cattle;
Behaviour
1. Introduction
Milking cluster attachment failures during automatic milking occur in the range from
Ž . Ž .
a few percent of cases to 12% Ipema et al., 1997 and 15% Mottram et al., 1995 . On commercial farms, after milking failure a cow is mostly diverted to a separate area and waits for a stockman, who takes her back to the robot and supervises robot attachment.
Ž .
In experimental studies with an automatic milking system AMS where cow behaviour was studied, cows were not separated after milking failure. The stockman intervened twice a day to ensure that any cows with failed milking andror too long an interval
Ž .
since the previous milking were milked Stefanowska et al., 1999a,b . These cows were brought to the milking robot individually. Usually, the same cows, ones whose udder conformation is less convenient for robot attachment, failed to be milked. It was observed that when a visit to the AMS ended with a milking failure, cows returned to the AMS of their own free will after an average of 2 h, whereas milked cows returned
Ž .
after an average of 5 h Stefanowska et al., 1999a,b . It seems likely that a cow returns
Ž
after a milking failure because she wants to eat concentrate dispensing stops after
.
milking failure , or she expects to be milked, or both. It is not known whether cluster attachment failure has implications for the well-being and milk yield of a cow. It is difficult to study the effects of milking failure in conditions of voluntary visits to the
Ž
robot, since the conditions of individual cases are uncontrollable different milking
.
intervals; different situation related to rest and feeding . In these circumstances it is difficult to explain individual reaction to milking failure and to compare individual cases with each other. However, a trial on the effects of omitted milking in a traditional milking parlour might simulate the possible effects of cluster attachment failure. It proceeds under human supervision and can be controlled adequately. This paper describes such a trial.
Ž .
and 0.7 kg. Milk yield was not significantly different after a 60-min interval, possibly because the effect of a delay of milking after stimulation disappeared during the 60-min interval while milk production resumed. The effect of delay of milking on cow behaviour was not investigated.
Our aim was to estimate the well-being of unmilked cows by comparison with milked cows and to relate these findings to the situation of automatic milking. Our hypothesis
Ž .
was that omitted milking cluster attachment failure unsettles a cow in some way and this will be reflected by her behaviour.
2. Materials and methods
In this trial we studied the behaviour of cows after their return from the milking
Ž
parlour where some had been milked and others not. For ethical reasons not subjecting
.
the cows to unreasonable levels of discomfort it was considered that an observation period of 1 h was enough to reveal any effect of omitted milking; moreover, the cows in the trial were in the second half of lactation. The unmilked cows were milked immediately after the observation period had ended.
2.1. Animals, housing, procedures
We aimed to take into account all behavioural traits that could be influenced by omitted milking. The milking order during all visits to the milking parlour was registered, as were any aggressive interactions between cows and where these occurred. The milk production during the trial was also monitored.
The trial was carried out with 12 Holstein–Friesian cows, divided equally between
Ž .
first and second lactations. On average, the cows were 209 SDs42 days in their lactation. Mean milk yield at the beginning of the trial was 21.4 kgrday for cows in their first lactation and 27.9 kgrday for cows in their second lactation. Ten cows were in calf and two barren.
Ž .
The cows were kept in a compartment of a loose housing system Fig. 1 with a slatted floor, a lying area with the same number of cubicles as the number of cows, and
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a separate feeding area with six automatic feeders Devir et al., 1996 . One watering trough and one salt block were placed in the feeding area. Cows were fed a complete
Ž .
diet mixture of grass silage, corn silage and concentrate with 43.5% of dry matter ad libitum in an automatic forage installation. The cows were given 0.5 kg concentrate per milking.
The compartment for the experimental cows was located near the milking parlour
ŽFig. 1 . During a habituation period of 12 days the cows were milked 2 times per day. Žat 05.45 h and 15.45 h and learned to follow routine that was applied in the trial.
Fig. 1. Layout of compartment of the cubicle house used in the trial.
compartment. In the habituation period the cows were subjected to an identical proce-dure of udder preparation executed by a milker. This proceproce-dure consisted of four circular cleaning movements on the surface of the udder and three squeezes per teat.
After the habituation period the 16-day trial with omitted milkings started. The omitted milkings were applied only during the afternoon milkings. Each day, 3 of the 12
Ž .
cows never the same 3 as the previous day, and always a different trio were deliberately omitted from milking. If the preparation of the udder was not followed by milking, these cows were released from the milking stalls 2 min later. This mimicked the robot milking situation where the attachment attempt is aborted after 2 min
ŽStefanowska et al., 1999a . During the 16 days, each cow was subjected to four omitted.
milkings. The omitted milkings for the same cow were at least 2 days apart.
Immediately after an observation period of 1 h, all cows were simultaneously herded into the waiting area in front of the milking parlour for the three unmilked cows to be milked. The nine previously milked cows walked through the milking parlour, but the three unmilked cows were milked after another preparation of the udder.
2.2. Collection of data
minute, was taken from the video registration: eating, standing in feeding area or lying area, standing in cubicles and lying. Furthermore, the time until the occurrence of eating, drinking, lying, urination and defecation was taken from video rounded off to the nearest
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minute. The occurrence of aggressive acts including physical contact was recorded,
Ž
noting the cows involved and the output of aggressive interaction e.g., aggressor and
.
recipient .
Ž .
Individual intake duration, amount of a complete diet as well as milk yield were registered automatically.
Ž
After omitted milking all cows were observed visually for leakage of milk
qualita-.
tive: yes or no .
Milking order of cows was observed during morning and afternoon milking as well as during the third visit to the milking parlour. The milking order was defined on the basis of whether the cow came to the milking parlour within the first batch of six cows. In this
Ž
way, after the 16 days of the trial, each cow had received three numbers each in the
.
possible range 0–16 equal to the numbers of visits in which she came within the first batch of six cows during the morning, the afternoon and also during the third herding into the milking parlour. Additionally the order of entering of the compartment after
Ž
afternoon milking defined in the same way as for the milking parlour, e.g., being one of
.
the first six cows was observed.
One important aspect of this experiment was that after each milking the first batch of six cows had to wait in the return alley for about 10 min until they were joined by the
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remaining six cows arriving from the milking parlour see Fig. 1 . The waiting cows may have urinated andror defecated. It was also possible that waiting in the return alley affected the behaviour during the observational period. To avoid complications, the observations started after all cows had entered the compartment, rather than as soon as the first six cows entered the compartment. This enabled us to observe each cow while within the entire group: this is especially important in the context of aggressive interactions.
2.3. Data analyses
Ž
The Genstat 5 statistical package was used for the analyses Genstat 5 Committee,
.
1998 .
Ž .1 The time budgets for five different activities were analysed by a generalised linear
Ž .
model GLM . The probabilities of the occurrence of the activities mentioned above were transformed to log-probabilitieshj where j is the index for the category. The effect of a treatment on these probabilities was assumed to be linear on the log-scale:
hjishjqbji
Ž .
1Ž .
where bji represents the effect of the factor level i isomitted milking on the
Ž
log-probability for category j see McCullagh and Nelder, 1989 for more detailed
.
information on models for the analysis of categorical data .
Ž .2 Occurrence of different events yesŽ rno during the 1-h observational period was.
Ž .
analysed by a generalised linear mixed model GLMM using a logistic link function:
where m is a binary variable representing whether or not an event has occurred, b
Ž
represents fixed effects and u represents the random effects for cows McCullagh and
.
Nelder, 1989; Engel and Keen, 1994 for the analysis of binary data .
Ž .3 The time until the occurrence of different events was analysed according to a
Ž .
linear mixed model LMM , where the variance was assumed to be constant and
Ž .
normally distributed Engel, 1990 :
msbxquz
Ž .
3wherem represents the expected value of the time that has elapsed until the occurrence
Ž .
of a certain event and b and u are the same as in Eq. 2 . Analysis of time until occurrence is complicated by the fact that observations ended after 60 min. This was corrected by the method described by Taylor for so-called censored observations
ŽTaylor, 1973 ..
Ž .4 The number of aggressive interactions induced by a certain cow within the 1-h
Ž .
observational period was analysed by a generalised linear mixed model GLMM with a logarithmic link function:
log
Ž
m.
sbxquzŽ .
4wherem is the number of aggressive interactions and b is a variable representing the effect of omitted milking or milking on the aggression of a cow. It was assumed that
Ž
variance increases proportionally to the expected response value see McCullagh and
.
Nelder, 1989 for loglinear models on counted data .
Ž .5 Data from the automatic forage installation and data about milk production were
Ž . Ž .
analysed with a linear mixed model LMM see Eq. 3 .
Ž .6 The number of changes between automatic forage feeders was analysed with a
Ž . Ž .
generalised linear mixed model GLMM see Eq. 4 .
Ž .
The analyses 1–6 included the effect of rank in the milking order, as well as the
Ž .
effect of lactation number and interaction between these factors if any .
The milking order of cows during three visits to the milking parlour and also the order during return to the compartment after the second visit to the milking parlour were
Ž .
compared using a Spearman correlation coefficient Siegel and Castellan, 1988 . The place where aggressive interactions between cows occurred after milking and after
2 Ž .
omitted milking was compared by a x test Siegel and Castellan, 1988 .
3. Results
The observations on the behaviour of milked and unmilked cows started immediately after the entire group had entered the compartment after returning from the milking
Ž .
parlour. The entrance led to the lying area see Fig. 1 , from where at least half of the cows went immediately to the feeding area. In the course of 1 h, the percentage of cases of eating or standing in the feeding area remained the same, whereas the percentage of cases of lying increased gradually, though this tendency was less marked in the
Ž .
Fig 2. Activities of cows during the 1-h observational period after milking or omitted milking.
always higher for the unmilked than for the milked cows. The impression from Fig. 2 is
Ž .
confirmed by the analysis of time budget per hour see Table 1 . The difference was significantly attributed to the cows that were in the first batch that came to the milking
Ž .
parlour. After omitted milking, these cows stood longer in the cubicles 14.2 min of 1 h
Ž .
and lay less 5.4 min of 1 h than milked cows for whom the corresponding figures were
. Ž .
7.0 min for standing and 16.4 min for lying in cubicles P-0.01 . There was no significant difference between milked and unmilked cows in time spent on eating and
Ž .
standing in the eating or in the lying area taken from video .
The probabilities of the occurrence of eating, drinking and lying as well as defecation and urination and the predicted time intervals for the occurrence of these activities in milked and unmilked cows are given in Table 2. Probability of cows eating forage was
Ž . Ž . Ž
80% SEMs4% after milking and 85% SEMs7% after omitted milking difference
. Ž .
not significant . Probability of cows drinking was 73% SEMs4% after milking and
Ž . Ž .
Table 1
Ž .
Predicted time budget min of 12 cows during 1 hour following their visit to the milking parlour. In 16 trials,
Ž . Ž .
each cow had not been milked 4= or milked 12=; standard error of means in parenthesis
Order of coming to the milking parlour Activity Milked cows Unmilked cows
Ž . Ž .
First batch of six cows eating forage 13.9 1.6 19.0 3.5
Ž . Ž .
standing in eating area 17.2 1.8 15.4 3.1
Ž . Ž .
standing in lying area 5.5 1.0 6.0 1.9 a
Ž . Ž .
standing in cubicle 7.0 1.1 a 14.2 3.0 b
Ž . Ž .
lying 16.4 1.7 a 5.4 1.8 b
Ž . Ž .
Second batch of six cows eating forage 12.7 1.6 14.2 2.8
Ž . Ž .
standing in eating area 13.7 1.7 14.9 2.8
Ž . Ž .
standing in lying area 5.6 1.0 6.1 1.8
Ž . Ž .
standing in cubicle 10.3 1.4 9.3 2.2
Ž . Ž .
lying 17.7 1.9 15.5 2.9
a Ž .
Different letters in one row indicate statistically significant difference P-0.01 .
Ž .
milked cows respective probabilities 64% and 36%, P-0.002 and the time interval
Ž
until urination was predicted to be shorter for unmilked cows 56 min versus 70 min for
.
milked cows, P-0.002 . Neither the probability of defecation nor the time interval to occurrence of defecation was significantly influenced by omitted milking.
The milking order was not reflected in the order in which the cows entered the
Ž .
compartment prior to the start of the observations rss y0.43, not significant , because the cows moved around in the return alley. However, milking order was reflected in the use of the automatic forage installation. Cows that were in the first batch to enter the milking parlour spent more time eating, changed feeding places more and ate more feed. Intake of feed was also influenced by lactation: during the 1-h observation period, cows in the second lactation ate 4.8 kg of forage on average, whereas cows in the first
Ž .
lactation ate 3.6 kg P-0.05 . The omitted milking did not significantly influence time
Table 2
Probability of occurrence of different activities for the 12 cows during 1 h after returning from the milking parlour, where three cows had been subjected to omitted milking, and predicted time until their occurrence for milked and unmilked cows; standard error of mean in parenthesis
Activity Milked cows Unmilked cows
Ž . Ž .
Probability of activity eating forage 0.80 0.04 0.85 0.07
Ž . Ž .
drinking 0.73 0.04 0.71 0.07
Ž . Ž .
lying down 0.59 0.05 0.55 0.08
Ž . Ž .
defecation 0.48 0.05 0.48 0.08
a
Ž . Ž .
urination 0.36 0.05 a 0.64 0.08 b
Ž . Ž . Ž .
Time until occurrence of activity min eating forage 33.1 4.2 31.4 2.4
Ž . Ž .
drinking 34.5 4.2 43.0 2.4
Ž . Ž .
lying down 52.0 4.1 57.1 2.4
Ž . Ž .
defecation 61.9 4.7 66.8 2.7
Ž . Ž .
urination 70.2 4.0 a 55.8 2.3 b
a
Ž .
spent in the forage installation, the forage intake or the rate of eating forage, as analysed on the basis of data from automatic forage installation.
One hour after an omitted milking, cows gave on average 11.48 kg milk; this was
Ž . Ž .
more than what normally milked cows gave 10.81 kg, P-0.01 Table 3 . The following morning the opposite was true: cows subjected to omitted milking the previous afternoon gave 13.38 kg milk on average, whereas cows normally milked gave
Ž . Ž
14.50 kg P-0.01 . Daily milk yield calculated as afternoon plus next morning milk
.
yields on days with omitted milking averaged 24.88 kg in comparison with 25.29 kg on
Ž .
days without omitted milking P-0.05 . Cows that were most frequently in the first batch during afternoon milking had a higher daily milk yield and a higher morning milk yield. This relation was not found for the afternoon milk yield, because of the direct effect of omitted milking.
Throughout the experiment, the same milking order was observed, as indicated by the
Ž .
correlation coefficient: rss q0.69 between morning and afternoon milking P-0.05 ;
Ž .
rss q0.78 between afternoon milking and the third visit 1 h later of all cows to the
Ž . Ž .
milking parlour for the three unmilked cows to be milked P-0.01 .
Table 3
Ž .
Predicted milk yield of experimental cows kgrcow and factors found to have significant influence on it; standard error of mean in parenthesis
Milk production in the afternoon
cows normally milked cows milked 1 h later
a
cows normally milked cows milked 1 h later
Ž . Ž .
days without omitted milkings days with omitted milking
Ž . Ž .
Different letters in one row indicate a statistically significant difference a,b at P-0.01 level; c,d at
.
The average number of aggressive interactions was 2.2 per cowrh after milking and
Ž .
2.6 per cowrh after omitted milking difference not statistically significant . The number of aggressive interactions was not related to the milking order or to the lactation number. The proportion of numbers of being the aggressor to the sum of being the aggressor and of being the recipient of the aggression was similar after milking and after
Ž .
omitted milking rss q0.86, P-0.01 . Analysis of where the 468 aggressive
interac-Ž .
tions 337 of milked cows and 131 of cows after omitted milking took place revealed
Ž .
that cows were most aggressive at the forage feeders 43.4% of cases and the water
Ž .
trough 28.0% of cases . Aggressive interactions also took place, but less, in the feeding
Ž . Ž . Ž
area 13.5% of cases , around the salt block 7.0% of cases and in the lying area 6.6%
. Ž
of cases . Pushing a cow away from her lying place happened exceptionally seven
. 2
cases, 1.5% of all . The x test revealed no difference in the distribution of the location of the aggressive acts of milked and unmilked cows.
Milk leakage from the udder was observed in 60% of cases after omitted milking. In
Ž
5 out of 12 cows milk leakage was always observed after omitted milking e.g., for four
. Ž
occasions of omitted milking , in three cows it was never observed e.g., during any of
.
four occasions ; milk leakage was observed irregularly in the remaining four cows after omitted milking. No relation was found between milk leakage after omitted milking and behaviour after omitted milking or milk yield.
4. Discussion
4.1. Experiences of cows induced by omitted milking
It was assumed that cows perceive a mismatch between the familiar daily routine
Žcoming to milking parlour, preparation of the udder, milking and the outcome of the.
Ž .
visit no milking . There would have been physical sensations too: during preparation for milking the oxytocine reflex stimulates inflow of milk into the cistern of the udder, and therefore if no milking follows, the udder is likely to become distended. Incidences of leakage of milk observed after omitted milking were also registered in previous research in some cows that were brought in groups to the milking robot but had to wait
Ž .
their turn Stefanowska et al., 1995 as well as in cows waiting for access to a traditional milking parlour. The leakage is a consequence of milk accumulating in the cistern of the udder and is reinforced by preparation for milking not followed by milking. Cows differ in the occurrence of milk leakage, depending on differences in milk yield, individual reactivity and, last but not least, the difference in the functioning of the small sphincter muscles closing the milk canals of teats. It was assumed that omitted milking was experienced by cows externally as an unexpected situation and internally as pressure or at least as the lack of the familiar feeling of a milked-off udder.
were not selected for milking until they were in the milking stall with a robot: cows after milking failure or a no-milking visit urinated more often in the exit area from milking
Ž .
stalls than milked cows Stefanowska et al., 1999a . Furthermore, in three trials on the behaviour of cows subjected to ‘‘walk-through’’ selection on their way to a milking robot, it was observed that cows refused access to the robot urinated in the passage with ‘‘walk-through’’ selection more frequently than cows for whom the gate to the milking
Ž .
stalls with robot had opened Stefanowska et al., 1999b . The urination was presumably
Ž .
the cows’ response to the uncertainty about their situation. Hopster 1998 reported the occurrence of elimination by cows exposed to a new environment, but did not
distin-Ž .
guish between urination and defecation. Marchal et al. 1995 observed a decrease in elimination by cows after habituation to an automatic milking system. The empirical observations of farmers are that elimination increases after the installation of a new
Ž .
milking parlour. Kilgour and Albright 1971 suggested that stress stimulated cows to defecate and urinate. It is not known why in the present trial as well as in earlier trials
Ž . Ž .
reported by Stefanowska et al. 1999a,b the given situation with stress factor had more impact on urination than on defecation.
Another noteworthy result was that cows that came to the milking parlour in the first batch and were subjected to omitted milking stood significantly longer in the cubicles and lay significantly shorter than milked cows during the following period of 1 h. It seems probable that because they were more motivated for milking they experienced
Ž
more disruption. Moreover, because they had a somewhat higher milk yield 26.0 kg of milkrday in comparison to 23.2 kg of milkrday for cows that were more frequently in
.
the second batch they experienced more discomfort than cows from the second batch.
Ž .
Ipema et al. 1988 reported that high yielding cows stood longer in cubicles than low yielding cows and that after introduction of more frequent milking they began to lie longer in the cubicles. The cows that were present most frequently in the first batch were four cows in second lactation and two cows in first lactation. They were also in the first batch during the third visit to the milking parlour for milking the three unmilked cows. This suggests that a cow’s motivation to lead the way to the milking parlour may be related to milk yield, age, but maybe also to individual attribute.
4.2. Does omitted milking stress the cow?
The question arises whether we can qualify the experience of omitted milking as
Ž .
stress. Hopster 1998 defined stress as a state when the expectations or objectives of an
Ž .
animal do not match the observed and sensed environment external or internal . Unspecific reactions to stressors take place when influencing factors may exert effect on
Ž . Ž .
psychological status uncertainty, fear Hopster, 1998 . In this context we may hypothe-sise that urination after omitted milking is an unspecific reaction to the disturbance of
Ž .
daily routine e.g., omitted milking . During stress, the concentration of adrenalin and noradrenalin in the blood and also locally released noradrenalin inhibit milk removal
ŽHamann, 1994 . Algers 1998 is convinced that stress can affect milk production, but it. Ž .
is difficult to state whether such effects are direct or indirect. In our trial, cows after omitted milking gave 0.7 kg milk more during the milking 1 h later than cows normally
Ž . Ž .
of the udder and to the extra hour elapsed before milking. During the next morning cows
Ž .
after omitted milking gave 1.1 kg milk less than cows normally milked P-0.01 . This can be attributed to the 1 h shorter milking interval. However, the difference of 0.4 kg
Ž .
milk less P-0.05 on days with omitted milking than on days without omitted milking might be caused by the milk ejection process being interrupted during days with omitted
Ž .
milking; this agrees with the findings of Bruckmaier and Blum 1998 on oxytocine release and milk removal in ruminants.
It is clear that omitted milking did not influence either the time spent in the forage installation or the amount of forage eaten. All cows ate intensively during the 1 h after returning from the milking parlour. During that hour they ate on average 1.9 kg of dry matter from the mixed ration. Compare this with a daily intake of circa 20 kg of dry matter from forage and concentrate as registered in the same installation during another
Ž .
trial Metz-Stefanowska et al., 1993 . The rate of eating of the mixed ration was circa 100 g dmrmin. This is higher than the mean daily forage eating rate of 83 g dmrmin as
Ž .
reported by Metz-Stefanowska et al. 1993 , probably because eating intensity depends on kind of forage and way of rationing and it varies throughout the day.
Metz-Ž .
Stefanowska et al. 1992, 1993 described that after milking in a traditional milking
Ž
parlour and also after robotic milking, cows were at the feeding rack optionally
.
automatic feeding installation much more frequently than during any other time. Tyler
Ž .
et al. 1997 observed that when forage was available, cows stayed in the feeding area after milking longer than when no forage was available.
It is interesting that the number of aggressive acts and the individual proportion of being aggressorrrecipient was not influenced by omitted milking either. The average number of 30 aggressive acts within the group during the 1 h of observations agrees
Ž .
with observations of Metz 1983 on aggressive interactions between 14 cows provided with a feeding rack with 7 places and fed ad libitum. According to Metz, the described situation was not as competitive as it can be in case of not feeding ad libitum. Omitted milking was not a situation that changed aggression beyond an established level in a group.
4.3. Relating the results of research on omitted milking to robotic milking failures
In other research conducted in circumstances of automatic milking, cows returned to
Ž .
the AMS after milking failure earlier than milked cows Stefanowska et al., 1999a,b . Compared with the other cows they returned to the AMS without lying or eating more
Ž .
often Ketelaar-de Lauwere et al., 2000 . The cows with recurrent milking failure because their udder conformation was less suitable for robot attachment could develop their own strategy to try to resolve their situation by returning, with whatever motivation
Žto eat concentrate andror to be milked . This was not the case in our trial: during the.
third visit to the milking parlour the unmilked cows did not break with the established milking order. It is widely accepted that cows that undergo daily routine as a group react
Ž .
to stress more passively Hopster, 1998 . After failure of cluster attachment, the cows in
Ž .
influ-Ž .
enced their time budget idle time at the expense of eating or lying . Efficient use of time budget is very important for high yielding cows because they must eat and lie a lot. These cows urinated in the exit area of the AMS more often than milked cows
ŽStefanowska et al., 1999a ..
In the case of a cowshed with a robot and animals given access to the pasture dependent on milking status, cows may be denied access to outdoors after milking failure of the robot. They may pay many unsuccessful visits to the robot before finally being allowed outdoors, mostly after the farmer has intervened. It is essential to establish some time limits for human intervention in the case of milking failure, especially for high yielding cows and when successful milking is a prerequisite for being
Ž
allowed to leave the barn or during the periods of longer absence of the farmer e.g., at
.
night . It would be possible to estimate the well-being of cows after the failure of the robot attachment on the basis of their activities following the failure by looking at their idle time and occurrence of urination.
The leakage of milk observed after omitted milking as well as after cluster attachment failure during robotic milking forms a risk for the udder health of cows. Elbers et al.
Ž1998 reported that leakage of milk from the udder is one of the factors associated with.
clinical mastitis at herd level.
5. Conclusions
Ž .1 After omitted milking, all cows showed some signs of discomfort urination ;Ž . Ž
those that visited the milking parlour most frequently in the first batch more milk and
.
higher motivation showed some signs of discomfort by standing in the cubicles afterwards instead of lying.
Ž .2 The leakage of milk that can occur after omitted milking or after cluster attachment failure during robotic milking is a risk factor for mastitis.
Ž .3 The treatment was not so influential that it caused cows whose milking had been
omitted to change the way they visited the milking parlour when they were finally brought for milking together with already milked cows. This is supported by other
Ž .
findings that during 1 h after omitted milking cows did not eat more or less and were
Ž .
not more or less aggressive than milked cows. A similar tendency was observed for drinking.
Ž .4 It seems probable that this approach will be useful for estimating possible direct
effects of a robot milking failure on a cow. Future studies should examine the consequences of a robot milking failure in high yielding cows and for a period longer than 1 hour.
Acknowledgements
References
Algers, B., 1998. What is animal stress and how does it affect milk production? In: Proc. of the 25th International Dairy Congress Aarhus 21–24.09. pp. 27–32.
Bruckmaier, R.M., Blum, J.W., 1998. Oxytocin release and milk removal in ruminants. J. Dairy Sci. 81, 939–949.
Devir, S., Hogeveen, H., Hogewerf, P.H., Ipema, A.H., Ketelaar-de Lauwere, C.C., Rossing, W., Smits, A.C., Stefanowska, J., 1996. Design and implementation of a system for automatic milking and feeding. Can.
Ž .
Agric. Eng. 38 2 , 107–113.
Elbers, A.R.W., Miltenburg, J.D., De Lange, D., Crauwels, A.P.P., Barkema, H.W., Schukken, Y.K., 1998. Risk factors for clinical mastitis in a random sample of dairy herds from the southern part of Netherlands. J. Dairy Sci. 81, 420–426.
Engel, B., 1990. The analysis of unbalanced linear models with variance components. Stat. Neerl. 44, 195–219.
Engel, B., Keen, A., 1994. A simple approach for the analysis of generalised linear mixed models. Stat. Neerl. 48, 1–22.
Genstat 5 Committee, 1998. Genstat TM 5 release 4.1: Reference Manual. Clarendon Press, Oxford, UK. Hamann, J., 1994. Possibilities for optimal interaction between cow and machine. In: Proc. of the International
Symposium Prospects for Future Dairing: A challenge for Science and Industry, 13–16 June, 1994, Tumba, Sweden. pp. 65–74.
Hopster H., 1998. Coping strategies in dairy cows. PhD thesis, Wageningen Agricultural University, 152 pp. Ipema, A.H., Ketelaar-de Lauwere, C.C., de Koning, C.J.A.M., Smits, A.C., Stefanowska, J., 1997. Robotic milking of dairy cows. In: Proc. 3rd Internationale Tagung: Bau, Technik und Umwelt in der Land-wirtschaftlichen Nutztierhaltung, Kiel. pp. 290–297.
Ipema, A.H., Wierenga, H.K., Metz, J., Smits, A.C., Rossing, W., 1988. The effects of automatic milking and feeding on the production and behaviour of dairy cows. In: Proc. of the EAAP Symposium of the Commission on Animal Management and Health & Cattle Production, 1 July, 1988, Helsinki, Finland, EAAP Publication No. 40. pp. 11–24.
Ketelaar-de Lauwere, C.C., Hendriks, M.M.W.B., Zondag, J., Ipema, A.H., Metz, J.H.M., Noordhuizen, J.P.T.M., 2000. The influence of routing treatments on cows’ visits to an automatic milking system, their
Ž .
time budget and other behaviour. Acta Agric. Scand., in press .
Kilgour, R., Albright, J.L., 1971. Control of voiding habits. NZ J. Agric. 122, 31–33.
Marchal, P., Wallian, L., Rault, G., Collewet, C., 1995. Investigation on the behaviour of dairy cows during robotic milking. In: Proc. of 3rd International Dairy Housing Conference, 2–5 February, 1995, Orlando, FL. pp. 415–425.
Mayer, H., Schams, D., Prokopp, A., 1984. Effects of manual stimulation and delayed milking on secretion of oxytocin and milking characteristics in dairy cows. Milchwissenschaft 39, 666–670.
McCullagh, P., Nelder, J.A., 1989. Generelized Linear Models. 2nd edn. Chapman and Hall, London, UK.
Ž .
Metz, J.H.M., 1983. Food competition in cattle. In: Baxter, S.H., Baxter, M.R., MacCormack, J.A.C. Eds. , Farm Animal Housing and Welfare. Martinus Nijhoff Publishers, Boston, pp. 164–170.
Metz-Stefanowska, J., Huijsmans, P.J.M., Hogewerf, P.H., Ipema, A.H., Keen, A., 1992. Behaviour of cows before, during and after milking with an automatic milking system. In: Ipema, A.H., Lippus, A.C., Metz,
Ž .
J.H.M., Rossing, W. Eds. , Prospects for automatic milking. Proc. of the International Symposium Pudoc Scientific Publishers, Wageningen, pp. 270–277.
Metz-Stefanowska, J., Ipema, A.H., Ketelaar-de Lauwere, C.C., Benders, E., 1993. Feeding and drinking strategy of dairy cows after the introduction of one-way traffic into the loose housing system in the context
Ž .
of automatic milking. In: Collins, E., Boon, C. Eds. , Livestock Environment IV. 4th International Symposium. ASAE publication 03-93, Mich., USA. pp. 319–329.
Mottram, T.T., Hall, R.C., Spencer, D.S., Allen, C.J., 1995. The role of the cow in automatic teat attachment. J. Dairy Sci. 78, 1873–1880.
Pfeilsticker, H.U., Bruckmaier, R.M., Blum, J.W., 1996. Cisternal milk in the dairy cow during lactation and
Ž .
after preceding teat stimulation. J. Dairy Res. 63 4 , 509–515.
Stefanowska, J.,Sonck, B.,Keen, A., 1995. Behaviour of cows milked in fixed milking periods with automatic
Ž .
milking system on practical farms in Dutch . IMAG-DLO nota 95-07, Wageningen, Netherlands pp. 35. Stefanowska, J., Ipema, A.H., Hendriks, M.M.W.B., 1999a. The behaviour of dairy cows in an automatic milking system where selection for milking takes place in the milking stalls. Appl. Anim. Behav. Sci. 62, 99–114.
Stefanowska, J., Tiliopoulos, N.S., Ipema, A.H., Hendriks, M.M.W.B., 1999b. Dairy cow interactions with an automatic milking system starting with ‘‘walk-through’’ selection. Appl. Anim. Behav. Sci. 63, 177–193. Taylor, J., 1973. The analysis of designed experiments with censored observations. Biometrics 29, 35–43. Tyler, J.W., Fox, L.K., Parish, S.M., Swain, J., Johnson, D.L., Grasseschi, H.A., Gant, R., 1997. Effect of feed
