Agricultural and Food Science, Vol. 14 (2005): 346–353

346

A G R I C U L T U R A L A N D F O O D S C I E N C E

Vol. 14 (2005): 346–353.

Introduction of automatic milking system in Finland:
effect on milk quality

Heidi Salovuo, Pilvi Ronkainen, Antti Heino
Department of Food Technology, PO Box 66, FI-00014 University of Helsinki, Finland

Antti Suokannas
MTT Agrifood Research Finland, Agricultural Engineering Research, Vakolantie 55, FI-03400 Vihti, Finland

Eeva-Liisa Ryhänen
MTT Agrifood Research Finland, Food Research, FI-31600 Jokioinen, Finland, e-mail: eeva-liisa.ryhanen@mtt.fi

When an automatic milking system (AMS) is introduced on a farm the milking of cows and related work is
changed in many ways compared to farms with traditional milking systems. The objective of this paper was
to study the effect of the introduction of robotic milking in Finland on the composition and hygienic qual-
ity of milk. The study was carried out on three farms which were the first in Finland to introduce the auto-
matic milking system (Volontary Milking System™). Main chemical composition, somatic cell count, total
bacteria count, freezing point, free fatty acids, as well as Bacillus cereus, Clostridium spores, psychro-
trophic bacteria and coliforms were determined. After the introduction of the automatic milking system an
increase in somatic cell count and total bacteria count, psychrotrophic bacteria and coliforms was observed;
however, the differences were not statistically significant. The counts for Clostridium spores were at the
same level in the automatic and the conventional milking system. Bacillus cereus counts were very low in
both milking systems studied. Milk fat content and free fatty acids were elevated when AMS was intro-
duced. The introduction of AMS resulted in a significant increase (P < 0.01) in the freezing point during the
first three months. Though there was a trend that the overall quality of milk was impaired after the introduc-
tion of AMS, the quality of milk remained at premium class.

Key words: automatic milking, milk quality, somatic cell count, total bacteria count

Introduction

The first automatic milking system (AMS) was in-
troduced in the Netherlands in the beginning of the
1990s. Since then the AMS has been installed at a
number of farms in Europe, USA and Japan. In

Finland the system was introduced in 2000 and the
number of farms with AMS has steadily increased
since then.

The milking of cows changes in many ways
when traditional milking systems are replaced by
an AMS. The system includes voluntary visits for
milking and milking may occur more than twice

347

A G R I C U L T U R A L A N D F O O D S C I E N C E

Vol. 14 (2005): 346–353.

daily. In AMS human presence is not required dur-
ing milking. The machine prepares the cow for
milking independently according to settings that
are pre-programmed. The AMS includes the clean-
ing of teats in order to minimise the transmission
of mastitis or other harmful bacteria. The machine
is also programmed to indicate cows with abnor-
mal milk or milk with high somatic cell count
(SCC), by use of different sensors. The cleaning
process of milking equipment is automatic and is
carried out two to three times a day (24 h). After an
idle period the milking equipment is automatically
flushed. A flush is also given when a cow with ab-
normal milk, for example with a high SCC, has
visited the milking unit. (Schuling et al. 2001)

The effects of AMS on udder health and milk
quality have been evaluated in a number of experi-
ments. According to several studies the total bacte-
ria counts (TBC) and SCC and the free fatty acid
(FFA) level elevate after the introduction of AMS
(van der Vorst and Hogeveen 2000, Everitt et al.
2002, Rasmussen et al. 2002). However, no effects
(Klungel et al. 2000) or even an improvement
(Berglund et al. 2002) in SCC have also been re-
ported. The health, stage of lactation, (living) envi-
ronment and feeding of the animal affects the qual-
ity and chemical composition of milk (Akam et al.
1989). Elevated SCC are usually a sign of mastitis.
The TBC of milk is an indicator of the milking hy-
giene and the cooling of milk but can also imply
hazards in animal health (Hayes et al. 2000). It has
been suggested that factors related to AMS, such
as increased milking frequency, may also have an
impact on milk quality (Escobar and Bradley 1990,
Hamann and Gyodi 2000, Klungel et al. 2000, Ho-
geveen et al. 2001). Klungel et al. (2000) suggest-
ed that increased levels of free fatty acids may be
partly explained by shorter intervals. According to
Hogeveen et al. (2001) the variation in the milking
interval could be part of the explanation for an ap-
parent increase in SCC with automatic milking.
However, more research on the relationships be-
tween milking intervals and milk quality is re-
quired.

The present study was carried out as part of a
larger Finnish project investigating the impact of
AMS on udder health, animal welfare and milk

quality on three Finnish farms. The objective of
this work was to study the effect of the introduc-
tion of robotic milking on the composition and hy-
gienic quality of milk.

Material and methods

Dairy cows and milking
Three farms participated in this study; two private
farms (PF1 and PF2) and the Helsinki University’s
research farm. The farms are located in south-
western Finland. The research farm had an average
26 cows and private farms from 33 to 55 cows.
The cows were mainly of the Holstein Friesian
breed.

The cows were milked with the Voluntary
Milking System™ (VMS; DeLaval Group, Tumba,
Sweden). The mean milking frequency was 2–3
times per day. The AMS included the cleaning of
the teats with a special teat cup. After milking the
teat cups were automatically detached.

Collection and analysis of milk samples
Bulk tank milk samples were collected once a
week for three months on the research farm and
farm PF2 before the new milking equipment was
adopted. From farm PF1 samples were taken once
a week for one month before installation. After in-
stallation of the new equipment bulk tank milk
samples were collected twice a week during the
first three months and later on once a week from
all farms. The samples were taken for the first year
of using AMS during years 2000 and 2001. Before
drawing samples from farm tank, milk was stirred
for five minutes. Samples were stored in refrigera-
tor at +4°C and transported to the laboratory by
milk-lorry within 24 hours.

The results were compared to a reference group
which included the conventional milking parlour
of the research farm and 26 farms on a milk col-
lecting route located in south-western Finland.

348

A G R I C U L T U R A L A N D F O O D S C I E N C E

Salovuo, H. et al. Introduction of automatic milking

The fat, protein and lactose content (g l-1), SCC
(cells ml-1) and freezing point (°C) were deter-
mined using CombiFoss 6000, (Foss A/S, Hillerod,
Denmark), which is a combination of MilcoScan
FT 600 and Fossomatic 5000. The TBC (cfu ml-1)
was determined by automated fluorescence micro-
scopy (BactoScan 8000, Foss A/S, Hillerod, Den-
mark). The samples were analysed by Valio Ltd
Kouvola until 1 April 2001 and after that by Valio
Ltd Seinäjoki.

Milk samples to analyse of FFA were collected
once a week for seven months (research farm and
PF1) or for four months (PF2) after installation of
AMS. The FFA (mEq 100 g-1 fat) were determined
according to the method of FIL-IDF (1989) with
slight modification.

Bacillus cereus count in raw milk was deter-
mined using the ISO method 7932 (ISO 7932). In
total 19 samples were taken from the three AMS
equipments during a period from November 2001
to February 2002. Control samples (n = 20) were
taken from conventional milking parlours.
Clostridium spores were determined according to
Bergere and Sivelä (1990) from samples collected
once a week for seven months from April to Octo-
ber 2001 (n = 60). Samples from conventional
milking parlours (n = 84) were taken in April, May
and October 2001.

Psychrotrophic bacteria and coliforms were
also determined from bulk milk samples. Samples
were collected once a week for seven months after
the introduction of AMS. The determination of
coliforms was performed using a standard method
(FIL-IDF 1985). Psychrotrophic bacteria were de-
termined according to the IDF Standard (FIL-IDF
1991). All determinations were performed in du-
plicate.

Statistical analysis
The study was divided into five periods: the first
period was before AMS was adopted. The follow-
ing periods are 1–3, 4–6, 7–9 and 10–12 months
after installation. Mean values for the parameters
were calculated separately for each farm. From
these results an overall mean and standard devia-
tion were calculated.

Geometric means and standard deviation (SD)
were calculated for the SCC and TBC. Arithmetic
means and SD were calculated for fat, protein and
lactose content as well as for the freezing point.

The data were statistically analysed by analysis
of variance using SPSS 9.0 statistical software.
Statistical analyses were only performed to nor-
mally distributed parameters within the test group.
Within the group differences were tested with
Tukey’s test.

Results

Somatic cell count and total
bacteria count

TBC and SCC are presented in Table 1. The SCC
elevated from 142 000 (log 5.15) to 208 000 (log
5.31) cells ml-1 during the first nine months com-
pared to the situation before installation of AMS.
There was a slight improvement in SCC during the
last period, which can be seen as a decrease of cell
count by 32 000 (log 0.07) cells ml-1. The TBC was
elevated about three fold during the AMS period
from 3 800 (log 3.54) to 12 400 (log 4.07) cfu ml-1.
However, the increases in SCC and TBC were not
statistically significant (P > 0.05).

Coliforms and psychrotrophic bacteria
The count of coliforms bacteria in AMS was ele-
vated compared to traditional system. The colifor-
mic counts (geometric mean) were 57 cfu ml-1 and
18 cfu ml-1 for AMS-milk and conventional milk,
respectively. The variation in bacterial counts was
substantial; in the AMS-milk the highest counts
were 28 000 cfu ml-1 and in the reference group 9
900 cfu ml-1. As can be seen in Table 2, counts over
100 cfu ml-1 are more frequent in AMS milk than
in conventional milk. The count of psychrotrophic
bacteria in AMS-milk was 1 281 cfu ml-1 and was
10 fold higher than in the reference group (119 cfu
ml-1).

349

A G R I C U L T U R A L A N D F O O D S C I E N C E

Vol. 14 (2005): 346–353.

Table 1. The somatic cell count and total bacteria count in milk before and after the introduction of the
automatic milking system in three months periods.

Somatic cell count
(Log cells ml-1)

Total bacteria count
(Log cfu ml-1)

Geometric mean Standard deviation Geometric mean Standard deviation

Before introduction 5.15 0.16 3.54 0.54

After introduction, months
1–3 5.22 0.11 3.92 0.21
4–6 5.29 0.09 3.96 0.37
7–9 5.31 0.10 4.05 0.18
10–12 5.24 0.12 4.07 0.40

Table 2. Coliforms in milk produced using automatic
milking system (n = 56) or by conventional parlour
milking (n = 72).

cfu ml-1 Automatic
milking system

Conventional

n % n %

< 100 35 63.5 55 76.4
100–1000 15 26.8 15 20.8
> 1000 6 10.7 2 2.8

n = number of observations

Table 3. Clostridium spores in milk produced using
automatic milking system (n = 60) or by conventional
parlour milking (n = 84).

Most propable
number l-1

Automatic
milking system

Conventional

n % n %

< 300 50 83.3 69 82.1
300–1000 8 13.3 10 11.9
> 1000 2 3.3 5 6.0

n = number of observations

Bacillus cereus and Clostridium spores
In the present study the content of Bacillus cereus
in raw milk was very low (1 cfu ml-1) and bacteria
were detected in only two of the 39 raw milk sam-
ples studied (one positive sample in each groups).
The level of Clostridium spores is presented in Ta-
ble 3 showing that the majority of the raw milk
samples contained Clostridium spores under 300
l-1; 80 and 83%, in conventional and AMS, respec-
tively. Most of the samples had less than 1 spore
ml-1.

Main chemical composition, freezing point
and free fatty acids

The fat content of milk was elevated from 3.85 up
to 4.20% when AMS was introduced. However,
the increase was not statistically significant. Only
minor changes in protein and lactose content were
detected after introduction of AMS (Table 4).

The freezing point (FP) elevated significantly
(P < 0.01) from –0.531 to –0.518°C during the first
three months after the introduction of AMS. After
that the FP returned to the same level as before
AMS (Table 4).

The introduction of AMS elevated the level of
FFA. The mean values (±SD) were 0.52 ± 0.09 and
0.82 ± 0.16 mEq 100 g-1 fat for conventional milk-
ing (n = 40) and AMS (n = 88), respectively.

Discussion
Even though in the present study the TBC and
SCC had a tendency to increase, the quality of
milk still remained good. The upper limits for high
quality milk in Finland (E-class, extra) are for the
SCC 250 000 cells ml-1 (log 5.40) (3 months geo-
metric mean) and for the TBC 50 000 cfu ml-1 (log
4.70) (2 months geometric mean). In present study
the levels measured did not exceed these limits.

350

A G R I C U L T U R A L A N D F O O D S C I E N C E

Salovuo, H. et al. Introduction of automatic milking

Table 4. The chemical composition and freezing point of milk before and after the introduction of the automatic milking
system in three months periods. Values are arithmetic means.

Fat
(g l-1)

Protein
(g l-1)

Lactose
(g l-1)

Freezing point (°C)

Mean SD Mean SD Mean SD Mean SD

Before introduction 38.5 3.3 33.5 1.6 49.1 0.6 –0.531a 0.003

After introduction, months
1–3 39.7 1.4 32.1 1.0 48.1 0.4 –0.518b 0.002
4–6 42.0 2.0 33.1 0.5 48.4 0.2 –0.524ab 0.002
7–9 40.3 0.8 33.6 0.9 48.5 0.5 –0.528ab 0.005
10–12 40.4 1.1 33.6 0.2 48.6 0.5 –0.530a 0.002
a,b values within same column marked with different letters are statistically different (P < 0.01)
SD = standard deviation

Since 1998 over 90% of Finnish milk has been in
the E-class (Finnish Association for Milk hygiene
2004). It can be suggested that although some ad-
verse effects on milk quality were observed, the
overall hygienic quality of milk was not markedly
changed by the introduction of AMS. However the
amount of data was quite small, the variation in
counts was high and there was only three farms
participating in the study. Also the farms differed
from each other among other things in feeding, liv-
ing environment and hygienic status. Moreover, it
should be noted that one farm was a research
farm.

Others have also reported increases in TBC
and SCC due to the introduction of AMS. In the
Netherlands, according to Klungel et al. (2000),
the TBC increased from 8 000 to 19 000 cfu ml-1,
although the SCC did not rise after the introduc-
tion of AMS. Van der Vorst and Hogeveen (2000)
discovered that both TBC (from 8 000 to 12 000
cfu ml-1) and SCC (181 000 to 192 000 cells ml-1)
increased during the first year of automatic milk-
ing. In Denmark the TBC increased from 7 400 to
14 000 cfu ml-1 and the SCC increased from
246 000 to 302 000 cells ml-1 (Rasmussen et al.
2002). Increase in TBC may be caused by failures
in the cleaning system (Hayes et al. 2000). The
main reason for high SCC seems to be that farms
with AMS have been reported to have more new
infections during the first year of AMS (Rasmus-
sen et al. 2001). The same phenomenon was also
found in our larger project studying the impact of

AMS on udder health and animal welfare. Accord-
ing to this larger study significantly more infec-
tions were reported on all farms. Unreliable detec-
tion of subclinical infections was suggested to be
the most important reason for increase of infec-
tions (Suokannas et al. 2005).

Coliforms are an indicator of milking and cow-
house hygiene, especially environmental contami-
nation. According to Schuling et al. (2001), the
amount of coliforms in raw milk should be below
100 cfu ml-1. High counts of coliforms can be at-
tributed to coliform mastitis or environmental con-
tamination (Hayes et al. 2000). In this study the
high counts of coliforms might originate from en-
vironmental contamination which could have been
caused by temporary problems in the cleaning
process.

The count of psychrotrophic bacteria in AMS-
milk was 10 fold higher than in the reference
group. Sources of contamination of psychrotrophs
include soil, dust, air, water, vegetation and faeces
as well as milking equipment (Shah 1994). Higher
psychrotrophic counts in this study may be an in-
dication of failures in the AMS cleaning system.
Psychrotrophic bacteria can cause problems in the
manufacture of milk products, such as cheese mak-
ing, due to enzymatic activity when counts in-
crease to 104–107 cfu ml-1 (Cromie 1992). The
counts of psychrotrophic bacteria in this study re-
mained below 104 cfu ml-1 and represented a share
under 10% of total bacteria indicating good milk-
ing hygiene.

351

A G R I C U L T U R A L A N D F O O D S C I E N C E

Vol. 14 (2005): 346–353.

In our study the content of Bacillus cereus in
raw milk was very low. Bacillus cereus is a well
known organism of food poisoning and a common
contaminant in raw milk (te Giffel et al. 1995). The
spore content in milk is strongly associated with
the degree of contamination of the teats with soil
Christiansson et al. (1999). According to Chris-
tiansson et al. (1999) the milking equipment, the
air in the barn and animal feeding do not signifi-
cantly affect the spore content. Slaghuis et al.
(1997) reported that restricted pasturing during
summer reduced the contamination level of milk
and suggested that automatic milking will lower
the level of Bacillus spores in milk. To our knowl-
edge, so far no reports on the incidence of Bacillus
cereus in milk produced by an AMS have been
published. Our study suggests that AMS poses no
risk for contamination of aerobic spores.

Clostridium spores represent a minority of
bacteria found in raw milk, contamination levels
being around 10–102 spores ml-1. If lactating cows
are fed with heavily contaminated silage, levels
can increase to over 103 spores ml-1 (Aureli and
Franciosa 2002). Spores in milk originate from the
udder, and go from the teats and teat cups to the
milk. Dirty cows, spores in the air and milking
equipment also affect the butyric acid bacteria
content of milk (Stadhouders and Jørgensen 1990).
In contrast to our study, Rasmussen et al. (2002)
reported a significant increase in spores of anaer-
obes going from conventional to automatic milk-
ing, and this phenomenon was observed through-
out the first year. Most of the clostridial species
relevant in dairy products are nonpathogenic for
humans but can cause defects in final products
(Aureli and Franciosa 2002) such as late blowing
in hard cheese caused by Clostridium tyrobutyri-
cum (Klijn et al. 1995).

The fat content of milk tended to increase when
AMS was introduced. However, the differences
were not significant. This phenomenon may partly
be caused by shorter intervals in milking, which
was also seen in the traditional milking system
with increased milking frequency. Bruckmaier et
al. (2001) found that the fat content increases when
the milking interval is shorter. However, our re-
sults are in disagreement with the studies of Klun-

gel et al. (2000) and Everitt et al. (2002). Klungel
et al. (2000) found that fat and protein content was
significantly decreased after the introduction of
AMS (from 4.41 and 3.49 to 4.37 and 3.42, respec-
tively). In a Swedish study carried out by Everitt et
al. (2002) the fat (from 4.18 to 4.09%) and protein
(from 3.31 to 3.26 %) contents dropped after in-
stallation of AMS.

Elevated FFA levels indicate increased lipoly-
sis of milk. Escobar and Bradley (1990) suggest
that lipolysis is mainly caused by milk pipelines,
but it can also be caused by bacteria, such as psy-
chrotrophic bacteria (Shah 1994). The effect of
mechanical treatment on milk causing lipolysis
continues during storage (Needs et al. 1986). How-
ever, rapid cooling of milk has been reported to
delay the lipolysis (Escobar and Bradley 1990). A
recent report from Klungel et al. (2000) supports
our findings. They also found a significant increase
in FFA after introduction of AMS.

The FP of milk is measured to find out possible
water addition in milk. In Finnish dairies the limit
for rejection is adjusted to –0.512°C. A similar el-
evation of FP observed in our study, has also been
observed by others (Klungel et al. 2000, Rasmus-
sen et al. 2002). In our study the FP decreased after
the introduction period. This phenomenon has also
been reported by Everitt et al. (2002). Cleaning
procedures can leave residues of water in pipe
lines and thus changes in the FP can be a mark of
water in the pipelines. Further, air intake and more
frequent milking with the AMS can cause changes
in the FP of milk (Klungel et al. 2000).

Conclusion
The present work was conducted on the first Finn-
ish farms equipped with an AMS. The study
showed that the bulk milk was not seriously al-
tered by the implementation of AMS. The intro-
duction of AMS tended to increase SCC, TBC,
psychrotrophic and coliformic counts and the level
of FFA and fat content of milk in Finland. How-
ever, the changes were not statistically significant.

352

A G R I C U L T U R A L A N D F O O D S C I E N C E

Salovuo, H. et al. Introduction of automatic milking

There were no major differences in counts of
Clostridium spores and Bacillus cereus between
the conventional system and AMS. The freezing
point of milk was significantly increased after the
installation of AMS and returned to the original
level after an introduction period. Though the
overall quality of milk tended to be impaired after
the introduction of AMS, the quality of milk re-
mained at premium class.

Acknowledgements. The authors gratefully thank the farm-
ers and technical staff on the research farm for participat-
ing in this study. We also thank Valio Ltd for analysing
samples, and the Finnish Ministry of Agriculture and For-
estry and Valio Ltd for funding this research.

References
Akam, D.N., Dodd, F.H. & Quick, A.J. 1989. Milking, milk

production hygiene and udder health. FAO Animal Pro-
duction and Health Paper 78. 119 p.

Aureli, P. & Franciosa, G. 2002. Clostridium spp. In: Rogin-
ski, H. et al. (eds.). Encyclopedia of Dairy Sciences.
London, UK: Academic Press. p. 456–463.

Bergere, J.L. & Sivelä, S. 1990. Detection and enumeration
of clostridial spores related to cheese quality – classi-
cal and new methods. IDF Bulletin 251: 18–23.

Berglund, I., Petterson, K. & Svannersten-Sjaunja, K. 2002.
Automatic milking: effects on somatic cell count and
teat end-quality. Livestock Production Science 78:
115–124.

Bruckmaier, R.M., Macuhova, J. & Meyer, H.H.D. 2001.
Specific aspects of milk ejection in robotic milking: a
review. Livestock Production Science 72: 169–176.

Christiansson, A., Bertilsson, J. & Svensson, B. 1999. Bacil-
lus cereus spores in raw milk: factors affecting the con-
tamination of milk during the grazing period. Journal of
Dairy Science 82: 305–314.

Cromie, S. 1992. Psychrotrophs and their enzyme residues
in cheese milk. Australian Journal of Dairy Technology
47: 96–100.

Escobar, G.J. & Bradley, R.L., Jr. 1990. Effect of mechanical
treatment on the free fatty acid content of raw milk.
Journal of Dairy Science 73: 2054–2060.

Everitt, B., Ekman, T. & Gyllenswärd, M. 2002. Monitoring
milk quality and udder health in Swedish AMS herds.
In: The First North American Conference on Robotic
Milking, Toronto, Canada. V-72–V-75.

FIL-IDF 1985. Milk and milk products. Enumeration of colif-
orms – Colony count technique and most probable
number technique at 30°C. FIL-IDF Standard 73A:1985.
8 p.

FIL-IDF 1989. Milkfat products and butter. Determination of
fat acidity. FIL-IDF Standard 6B: 1989 (Provisional). 3 p.

FIL-IDF 1991. Milk. Enumeration of psychrotrophic micro-
organisms. Colony count technique at 6.5°C. FIL-IDF
Standard 101A:1991. 3 p.

Finnish Association for Milk Hygiene 2004. E-luokan osuus
maidosta 1998–2004. http://www.maitohygienialiitto.fi/
laatu_E-luokan_os_03.html. Cited 14 September
2004.

Hamann, J. & Gyodi, P. 2000. Somatic cell counts and elec-
trical conductivity in relation to milking frequency. Milch-
wissenschaft 55: 303–307.

Hayes, M.C., Ralyea, R.D., Murphy, S.C., Carey, N.R.,
Scarlett, J.M. & Boor, K.J. 2000. Identification and char-
acterization of elevated microbial counts in bulk tank
raw milk. Journal of Dairy Science 84: 292–298.

Hogeveen, H., Ouweltjes, W., de Koning, C.J.A.M. & Stel-
wagen, K. 2001. Milking interval, milk production and
flow-rate in an automatic milking system. Livestock
Production Science 72: 157–167.

ISO 7932. Microbiology – General guidance for the enu-
meration of Bacillus cereus – Colony count technique
at 30°C. 2nd edition. International Organization of
Standardization, Geneva, Switzerland. 1993.

Klijn, N., Nieuwnhof, F.F.J., Hoolwerf, J.D., van der Waals,
C.B. & Weerkamp, A.H. 1995. Identification of Clostrid-
ium tyrobutyricum as the causative agent of late blow-
ing in cheese by species-specific PCR amplification.
Applied and Environmental Microbiology 61: 2919–
2924.

Klungel, G.H., Slaghuis, B.A. & Hogeveen, H. 2000. The
effect of the introduction of automatic milking systems
on milk quality. Journal of Dairy Science 83: 1998–
2003.

Needs, E.C., Anderson, M. & Morant, S.V. 1986. Interaction
of factors which influence the extent of lipolysis during
milking and storage of raw milk. Journal of Dairy Re-
search 53: 203–210.

Rasmussen, M.D., Bolm, J.Y., Nielsen, L.A.H. & Justesen,
P. 2001. Udder health of cows milked automatically.
Livestock Production Science 72: 147–156.

Rasmussen, M.D., Bjerring, M., Justesen, P. & Jepsen, L.
2002. Milk quality on Danish farms with automatic
milking systems. Journal of Dairy Science 85: 2869–
2878.

Schuling, H.J., Verstappen-Boerekamp, J.A.M., Knapp-
stein, K. & Benfalk, C. 2001. Optimal cleaning of equip-
ment for automatic milking. Deliverable D16. Available
on the Internet: http://www.automaticmilking.nl. Cited
18 March 2003.

Shah, N.P. 1994. Psychrotrophs in milk: a review. Milchwis-
senschaft 49: 432–437.

Slaghuis, B., te Giffel, M.C., Beumer, R.R. & Andre, G.
1997. Effect of pasturing on the incidence of Bacillus
cereus spores in raw milk. International Dairy Journal 7:
201–205.

Stadhouders, J. & Jørgensen, K. 1990. Prevention of the
contamination of raw milk by a hygienic milk produc-
tion. IDF Bulletin 251: 32–36.

Suokannas, A., Salovuo, H., Ronkainen, P., Heino, A., Ho-
vinen, M., Kasanen, I., Raussi, S., Kaihilahti, J., Aisla,
A.-M., Saastamoinen, S., Alasuutari, S. & Manninen, E.
2004. Maidon laatu, eläinten utareterveys, käyttäytymi-
nen ja hyvinvointi automaattilypsyssä. Abstract: Effects

353

A G R I C U L T U R A L A N D F O O D S C I E N C E

Vol. 14 (2005): 346–353.

of automatic milking on the milk quality, udder health,
behaviour and welfare of cows. Maa- ja elintarviketa-
lous 62. 97 p.

te Giffel, M.C., Beumer, R.R., Slaghuis, B.A. & Rombouts,
F.M. 1995. Occurrence and characterization of (psy-
chrotrophic) Bacillus cereus on farms in the Nether-

lands. Netherlands Milk and Dairy Journal 49: 125–
138.

Van der Vorst, Y. & Hogeveen, H. 2000. Automatic milking
system in the Netherlands. In: Robotic milking proceed-
ings of the international symposium. Lelystad, Nether-
lands. p. 73–82.

SELOSTUS
Automaattisen lypsylaitteiston käyttöönoton vaikutus maidon laatuun
Heidi Salovuo, Pilvi Ronkainen, Antti Heino, Antti Suokannas ja Eeva-Liisa Ryhänen

Helsingin yliopisto ja MTT (Maa- ja elintarviketalouden tutkimuskeskus)

Lypsy ja siihen liittyvät työt muuttuvat tilalla, kun auto-
maattinen lypsyjärjestelmä otetaan käyttöön. Tämän tut-
kimuksen tarkoituksena oli tutkia automaattisen lypsy-
järjestelmän käyttöönoton vaikutusta maidon koostu-
mukseen ja laatuun Suomessa. Tutkimus toteutettiin
kolmella tilalla, jotka olivat ensimmäisiä automaattilyp-
sytiloja Suomessa. Maidon kemiallinen koostumus, so-
maattiset solut, kokonaisbakteerit, jäätymispiste, vapaat
rasvahapot, Bacillus cereus, klostridi-itiöt, psykrotrofit
bakteerit, ja koliformiset bakteerit määritettiin. Auto-
maattilypsyn käyttöönoton jälkeen somaattisten solujen,
kokonaisbakteerien, psykrotrofisten ja koliformisten

bakteerien määrät olivat korkeampia kuin perinteisesti
lypsettäessä, mutta erot eivät olleet tilastollisesti merkit-
seviä. Klostridi-itiöiden määrä oli samalla tasolla auto-
maattilypsymaidossa ja perinteisesti lypsetyssä maidos-
sa. Bacillus cereuksen määrä oli hyvin alhainen molem-
milla lypsytavoilla. Maidon rasvapitoisuus ja vapaiden
rasvahappojen määrä kohosivat automaattisen lypsyn
käyttöönoton jälkeen. Jäätymispiste kohosi ensimmäis-
ten kolmen kuukauden kuluessa laitteiston käyttöön-
otosta. Vaikka maidon laatu heikkeni, se oli edelleen E-
luokan maitoa.

Introduction of automatic milking system in Finland:effect on milk quality
Introduction
Material and methods
Results
Discussion
Conclusion
References
SELOSTUS