Table 6 Factors included in the PEC_{soil initial} calculation and their relationship with the result (positive correlation, negative correlation, constant factor, and factor neglected in the respective equation), the summarized trends in animal husbandry, and the expected effect on PEC_{soil initial}

Numerator

Daily dose of the active ingredient (a.i.)

/

/

–

Low dose^c

↓

Number of days of treatment

/

/

–

One shot^c

↓

Average body weight

/

–

–

Increased for some animal types

↑

Maximum body weight

–

/

–

Increased for some animal types

↑

Animal turnover rate per place per year

/

–

–

Decreases or remains constant

↓

Stocking density

–

/

–

Decreases or remains constant

↓

EU nitrogen spreading limit

°

–

–

Remains constant

°

Fraction of herd treatment

/

/

–

Decreases for many product groups

↓

Volume of dip used each milking

–

–

/

Decreases or disappears completely (antibiotics), while other remain constant^d

↓

Number of milkings per day

–

–

/

Increases slightly^e

↑

Number of days a dairy cow is in lactation

–

–

°

Remains constant

°

Concentration of the a.i. in the product

–

–

/

No or unknown evidence for changes

°

Fraction of dip entering dirty water

–

–

/

Remains constant

°

Denominator

Bulk density of dry soil

°

°

°

Remains constant

°

Depth of penetration into soil

°

°

°

Remains constant

°

N produced per year per place

\

–

–

Increased for some animal types

↓

Housing factor

\

–

–

Remains constant

°

Spreading rate for dirty water

–

–

°

Remains constant

°

Volume of water used to wash the milking parlor

–

–

°

Remains constant

°