Table 2 Parameters related to management, production, feeding, fertility and health given as average for herds with low (<0.06 μg Se/g), medium (0.06–0.11 μg Se/g) and high blood Se concentrations (>0.11 μg Se/g).

Herd characteristics

Number of herds

60

121

71

Se, μg/g blood

0.04

0.08

0.16

<0.001

Cow-years, number

21.4

19.3

27.5

<0.01

Milk yield, kg per cow-year

6 541

6 444

6 575

0.67

Replacement*

57.6

49.3

50.1

0.13

Culled cows*

55.7

46.5

46.9

0.26

Culled cows due to mastitis/SCC*

11.9

8.8

10.2

0.37

Culled cows due to other diseases*

1.9

1.7

2.5

0.06

Feeding

Total number of feeding units milk (FUM) per cow year

4 912

4 795

5 019

0.20

Concentrate, % of energy consumption

34.1

38.4

34.5

0.99

Grass silage, % of energy consumption

37.8

36.7

37.2

0.39

Pasture, % of energy consumption

14.3

13.5

11.9

0.35

Hay, % of energy consumption

1.8

3.5

2.5

0.59

NH₃ treated straw, % of energy consumption

1.2

1.4

2.5

0.01

Turnips, % of energy consumption

0.06

0.55

0.43

0.01

Potatoes, % of energy consumption

0.32

0.55

0.39

0.52

Brewer's grain, % of energy consumption

0.32

0.40

1.22

0.04

Fertility

FS-value

66

71

69

0.31

Calving interval, days

378.0

377.7

374.2

0.32

Anoestrus/silent oestrus**

5.2

4.2

4.3

0.84

Cystic ovaries**

1.1

2.1

1.0

0.59

Metritis**

1.7

1.9

1.5

0.83

Abortion**

0.5

0.5

0.4

0.35

Health

Severe/moderate clinical mastitis**

20.8

20.9

19.3

0.63

Clinical mastitis**

31.2

33.6

28.7

0.37

Sub and mild clinical mastitis**

15.2

17.3

15.6

0.80

All mastitis**

32.9

34.5

31.2

0.50

BMSCC, 1000 cells pr ml

137

132

155

0.03

Ketosis**

6.6

6.1

4.3

0.12

Teat treatments**

4.8

5.1

4.5

0.49

Retained placenta**

4.9

4.7

4.1

0.20

All disease treatments** (health and fertility)

64.8

62.0

57.5

0.09