Table 1 Average relative isoflux contribution (%) to the change of δ18O in body water by different fluxes.

From: Model explanation of the seasonal variation of δ18O in cow (Bos taurus) hair under temperate conditions

Flux

Whole year

Grazing seasons

Stall seasons

CO2 production

27

24

32

Drinking water

22

26

16

Air O uptake

14

11

18

Chemically bound O

10

8

13

Transcutaneous vapor

9

14

4

Nasally exhaled water

7

5

7

Orally exhaled water

6

5

5

Feed moisture

5

5

3

Air vapor

1

1

1

Organic products

1

1

1

Unfractionated output fluxes

0

0

0

  1. The relative isoflux contribution depends on the isotopic spacing between the flux and the body water and the amount of the flux.
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