----- Original Message -----

From: [log in to unmask] href="mailto:[log in to unmask]">Alexandre Myre

To: [log in to unmask] href="mailto:[log in to unmask]">[log in to unmask]

Sent: Friday, April 08, 2005 2:09 PM

Subject: Preservation of breath samples for 13CO2

Hi everyone,

As anyone ever heard of a possible contamination of 13CO2 values in cows and steers breath samples due to isotopic exchange between CO2 and methane ? If this is occuring, how fast could it affect carbon values ?

Thank you !

Alex

Alexandre Myre, Research Officer, University Laval.