Table S1 Reference material used for control of cadmium and zinc analysis by
atomic absorption spectrometry.
Reference
material
Cadmium (µg kg-1)
Zinc (mg kg-1)
Certified value Analytical results Certified value b
Analytical
results a
b
a
13±2
178±6.0
BCR No. 184
13.6±1.9
Lyophilised
(10.4-17.0)
(162-188)
[22]
[17]
bovine
166±3
muscle
BCR No. 185
279±43
Lyophilised
(159-345)
(117-141)
bovine liver
[16]
[17]
BCR No. 186
2.63±0.13(mg kg-
2.71±0.15
134±5.6
1)
(mg kg-1)
(110-145)
Lyophilised
pig kidney
298±25
133±6.1
(2.28-2.79)
142±3
128±3
[16]
[16]
a)
Mean ± SD, followed by (min-max values) and [number of samples].
b)
Certified value ± 95% confidence interval.
Table S2 Background data for all sampled cows (n = 79), including those that were
milk-producing at the start of the project (mean±SD; min-max)
Parameter
All cows
Conventiona
Organic
l
Number
79
43
36
Age (months)
Age at first calving
(months)
62±21
62±22
63±20
(30–126)
(31-126)
(30-122)
27±1.9
27±1.9
27±1.9
(24.4–32.8)
(24-33)
(24-32)
99±94
97±88
101±102
(0–415)
(0-376)
(0-415)
2.8±1.7
2.8±1.7
2.8±1.7
(1–8)
(1-8)
(1-8)
370±160
350±170
390±150
(3–855)
(3-677)
(144-855)
21330±1314
21140±1374
21560±1258
0
0
0
Days as dry cow
No. of calves
Days since calving
Total milk production (kg)
ECMa (kg)
(970-59800)
(970-59800) (2390-52450)
23260±1436
23040±1519
23530±1350
0
0
0
(1030–
(1030-65960) (2580-55460)
65960)
Months in productionb
Production index
(kg ECM/months in
32±19
32±20
33±17
(4.2-90)
(4.2-90)
(5.2-82)
700±140
700±160
690±110
(135–993)
(135-993)
(405-869)
production)
a) Energy
corrected milk (ECM)23 is the milk production converted to milk with an
energy value of 3.14 MJ kg-1, calculated as ECM (kg) = 0.25 kg Milk + 12.2 kg Fat +
7.7 kg Protein
b) Months
in production = Age – [Age at first calving + (Days as dry cow/30)]
Table S3 Cadmium and zinc concentrations in kidney, liver, muscle and mammary
tissue, mean±SD, (min-max) and [number of individuals] on a wet weight (WW) basis
in all sampled cows (n = 79), including those that were milk-producing at the start of
the project
Tissue
Element
All cows
Conventional
Organic
Kidney
Liver
Muscle
Mammary
Cd
400±150
420±140
370±150
(µg kg-1)
(140-810)
(160-780)
(140-810)
[79]
[43]
[36]
Zn
20±1.9
20±2.0
19±1.4
(mg kg-1)
(16-27)
(16-27)
(17-23)
Cd
41±21
43±19
39±23
(µg kg-1)
(13-130)
(13-89)
(14-130)
[79]
[43]
[36]
Zn
37±8.8
38±1
36±5.0
(mg kg-1)
(27-99)
(27-99)
(27-46)
Cd
0.50±0.15 b
0.51±0.16
0.50±0.13
(µg kg-1)
(0.21-1.1)
(0.21-1.1)
(0.21-0.75)
[78]
[42]
[36]
Zn
60±14
57±12
64±16
(mg kg-1)
(34-100)
(34-84)
(34-100)
Cd
0.54±0.37 c
0.62±0.44
0.44±0.24 a
(µg kg-1)
(0.19-2.2)
(0.19-2.2)
(0.21-1.5)
[74]
[39]
[35]
Zn
19±9.6
18±9.0
19±10
(mg kg-1)
(8.7-51)
(8.7-40)
(9.2-51)
a)
Significantly different (p<0.05, Students’ t-test) from the conventional system.
b)
88% of the samples above detection limit.
c)
69% of the samples above detection limit.