www.elsevier.comrlocateranireprosci
Robot milking and effect on reproduction in dairy
cows: a preliminary study
T.A.M. Kruip
a,), J. Stefanowska
b, W. Ouweltjes
ca
( )
Institute of Animal Science and Health ID-Lelystad , PO Box 65, 8200 AB Lelystad, Netherlands
b
IMAG-DLO, PO Box 43, 6700 AA Wageningen, Netherlands
c
Research Station for Cattle, Sheep and Horse Husbandry, PO Box 2176, 8203 AD Lelystad, Netherlands
Abstract
The aim of this study was to analyse whether automatic milking has an effect on reproduction in dairy cows. Probably the most important consequence of automatic milking is an increased milking frequency. More frequent milking means more production and thereby an extra threat for
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the energy balance during the first months of lactation. A deep negative energy balance NEB is often followed by negative effects on fertility. However, tested under experimental circumstances, automatic milking with a frequency not higher than 3 timesrday and with an individual management and feeding system has benefits for production and very little negative effects on reproduction. Experimental farms with automatic milking systems have fertility figures that do not differ from experimental farms with conventional milking systems. Additional and more data of automatic milking under farm conditions has to be collected and evaluated before the effect on fertility can be assessed with more certainty.q2000 Elsevier Science B.V. All rights reserved.
Keywords: Robot milking; Fertility; Dairy cow
1. Introduction
Automatic milking has been investigated during the last decade on some experimental
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farms Devir et.al., 1993; Ketelaar-de Lauwere et al., 1996 and on several commercial
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dairy farms Halachmi, 1999 and is now commercially available and introduced on about 200 farms in the Netherlands. The most important contribution to the dairy industry is the possibility to obtain more milk due to extra milkings by a minimum extra
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amount of labour. More frequent milking has been studied Poole, 1982; Amos et al.,
)Corresponding author.
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E-mail address: t.a.m.kruip@id.wag-ur.nl T.A.M. Kruip .
0378-4320r00r$ - see front matterq2000 Elsevier Science B.V. All rights reserved.
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.
1983; Waterman et al., 1983; Barnes et al., 1990; Campos et al., 1994 and its effect on increase of milk production is well established. From literature is known that the higher the production, in particular when food intake keeps not the balance with milk
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production, the deeper and longer lasting the period of a negative energy balance NEB , more lipolysis and proteolysis and loss of body condition. These processes have
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consequences for the fertility Butler et al., 1981; Butler and Smith, 1989; Senatore et .
al., 1996; Beam and Butler, 1994; Kruip et al., 1998 . However, it has been shown that a more frequent milking does not mean always a boost in the milk production. The
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increase is most obvious at the change from 2 to 3 timesrday milking Ipema, 1991 . A
further increase from 3 to 4 times milking had only a little increasing effect on milk production, but other problems like metabolic diseases and more days open have been
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reported Ipema, 1991 . Milking 7 timesrday caused severe problems with regard to
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udder health PRrID-Lelystad, unpublished results . Based on these publications, robot
milking with a frequency of at least 3 timesrday should have consequences for the
fertility but there are only a few data available up till now. Additional information related to automatic milking has to be collected and evaluated together with data about feeding. Combined with the automatic milking, information about milk yield, feeding and energy balance can be gathered and integrated into the management of the individual cow. Individual management in a Dairy Control and Management System has
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been developed Devir et al., 1993 and strives to reduce the NEB in order to
compensate for the effect of higher milk frequency on reproduction. The aim of this study is to analyse whether robot milking with a higher frequency than twice daily combined with or without an individual feeding management has an additional negative effect on reproduction.
2. Materials and methods
On three experimental farms, animals were kept in a loose housing system, equipped with an automatic milking system. In total, 415 lactations were analysed: 24 on farm 1, 255 on farm 2 and 136 on farm 3.
On farm 1, 24 animals were randomly divided into two groups: 14 animals had free access to the robot and were fed and milked individually according to a Dairy Control
and Management System whereas 10 animals were allowed to go 3 timesrday and were
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fed standard diet. The parameters studied were: onset of ovarian activity postpartum pp based on milk progesterone measured twice weekly and oestrous behaviour versus milk yield, loss of weight and loss of body condition score. None of the animals was inseminated before 100 days pp.
On farms 2 and 3, animals were offered the opportunity to be milked on average only
3 timesrday as the standard procedure whereas energy supply was corrected for
2.1. Statistics
All statistical analysis of the data collected on farm 1 employed regression analysis, performed separately for each of the response variables. The first analysis tested the differences between the two groups of different milking frequency, without any specific explanation of the possible causes of the difference. The second analysis was directed to explain possible effects of milking frequency, milk yield, percent body weight and change in body condition score on some reproductive events. Each of the explanatory variables was tested in combination with others and separately. Combined effects were tested with an F-test; effects of single explanatory variables were tested with a t-test. The analyses were carried out with Genstat 5 statistical package.
The differences between some fertility parameters of animals in the traditional
twice-daily milking farm routine and 3 timesrday robot milking were tested with a
t-test.
3. Results and discussion
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The 14 animals group 1 on farm 1 were milked with the mean frequency of
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4.5"0.2 SD timesrday and compared to group 2 with a mean milking frequency of
3.0 timesrday. Oestrous behaviour was observed 3 timesrday. Some most relevant
differences between the two groups are presented in Table 1. None of these were significantly different, except milking frequency.
Independently from the milking frequency the interval partus–first ovulation
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The effects of robot milking mean frequency of 2.6 on some fertility parameters of animals on farms 2 and 3 are presented in Table 2.
These results of robot milking do not differ from the fertility parameters of these two
farms with normal 2 times milkingrday.
Table 1
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Data means per cow related to milking frequency, milk yield, loss of body condition score during the first 30 days pp and data on number of corpora lutea and milk yield during days 31–100
Animals Group 1 Group 2 SD
Milking frequency per day 4.5 3.0 0.2
Milk yield day 1–30 30.4 31.1 6.3
Loss of body weight 2.9 3.0 2.9
Loss of body condition 0.32 0.63 0.3
First oestrus 37.6 50.5 31.8
Second oestrus 56.1 56.6 46.8
Milk yield days 31–100 34.3 34.5 6.7
Table 2
Effects of robot milking on some fertility parameters in the herds of farms 2 and 3
Herd Farm 2 Farm 3
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Interval calving–first insemination 81 days range 34–183 76.6 days range 40–216
Number of inseminationsrpregnancy 1.97 1.8
Proportion of pregnancies at day 56 56 58.8
Milking increase from 2 to 3 timesrday resulted in about 15% more milk and this is
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in agreement with data from literature Amos et al., 1983; Barnes et al., 1990; Campos
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et al., 1994 but no significantly higher food intake. Data from Ipema 1991 have shown that further increase of the milking frequency does give only very little increase in production, no more food intake and therefore a more pronounced negative effect on fertility. Based on the literature one may expect that more production without more
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intake means more NEB, more weight loss, more non-esterified fatty acids NEFAs , more metabolic diseases, later onset of ovarian activity, increase of number of insemina-tions per pregnancy plus an increase of the interval partus–conception. The findings and
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interpretations of Ipema 1991 are in agreement with these data from literature on the relation between milk yield and animal reproduction. However, a milking frequency of 3
timesrday combined with an individual management approach does not negatively
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affect oestrous behaviour Stefanowska et al., 1995, 1996 . Our data of robotic milking show furthermore that this procedure itself has no additional negative effects on animal health and reproduction. We conclude from the data presented that robot milking, provided a frequency of 3 timesrday, seems to have little negative effects on
reproduc-Ž .
tion but a benefit of more milk farms 2 and 3 . As said before, more milk normally means a reduction in fertility but the data show that this effect of yield and NEB can be
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reduced by management individual feeding combined with intensively heat detection . More data has to be collected and evaluated before the effects of robot milking on fertility can be assessed with more certainty.
References
Amos, H.E., Kiser, T., Loewenstein, M., 1983. Influence of milking frequency on productive and reproductive efficiencies of dairy cows. J. Dairy Sci. 68, 732–739.
Barnes, M.A., Pearson, R.E., Lukes-Wilson, A.J., 1990. Effects of milking frequency and selection for milk yield on productive efficiency of Holstein cows. J. Dairy Sci. 73, 1603–1611.
Beam, S.W., Buttler, W.R., 1994. Ovulatory follicle development during the first follicular wave postpartum in cows differing in energy balance. J. Anim. Sci. 72, 77, Suppl. Abstr.
Butler, W.R., Smith, R.D., 1989. Interrelationship between energy balance and post partum reproductive function in dairy cattle. J. Dairy Sci. 72, 767.
Butler, W.R., Everett, R.W., Coppock, C.E., 1981. The relationship between energy balance, milk production and ovulation in post partum Holstein cows. J. Anim. Sci. 53, 742.
Campos, M.S., Wilcox, C.J., Head, H.H., Webb, D.W., Hayen, J., 1994. Effects on production of milking three times daily on first lactation Holsteins and Jerseys in Florida. J. Dairy Sci. 77, 770–773.
Halachmi, I., 1999. Design methodology for the robot milk barn: modelling, simulating, validating and optimization. Thesis. Wageningen University. ISBN-90-8508-130-3.
Ipema, A.H., 1991. Onderzoek naar de optimale melkfrequentie. Nota nr 91-56. IMAG-DLO, Wageningen, October 1991.
Ketelaar-de Lauwere, C.C., Devir, S., Metz, J.H.M., 1996. The influence of social hierarchy on the time budget of cows and their visits to an automatic milking system. Appl. Anim. Behav. Sci. 49, 199–211. Kruip, Th.A.M., Meijer, G.A.L., Rukkwamsuk, T., Wensink, T., 1998. Effects of feed in the dry period on
fertility of dairy cows postpartum. Reprod. Domest. Anim. 33, 165–168.
Poole, D.A., 1982. The effects of milking cows three times daily. Anim. Prod. 34, 197–201.
Senatore, E.M., Buttler, W.R., Oltenacu, P.A., 1996. Relationship between energy balance and postpartum ovarian activity and fertility in first lactation dairy cows. J. Anim. Sci. 62, 17–23.
Stefanowska, J., Hogeveen, H., Devir, S., Benders, E., 1995. Occurrence of estrus in frequently milked cows
Ž .
in an automatic milking system. J. Dairy Sci. 78 Suppl. 1 , 380, Abstr.
Stefanowska, J., Devir, S., Hogeveen, H., Benders, E., 1996. The influence of frequent milking on the oestrous cycling of dairy cows milked automatically. IMAG-DLO Report 96-07. ISBN 90-5406-146-4.
