It depends on how the map you are playing on is set up. It will mow anything defined in the mower section of the maps’s xmls.
Viewing post in FS25 2020 John Deere W235 and W260 Swather comments
any idea when there will be a update to allow swapping out headers? like going from mowing to grain swathe modes? seems like it is just a mower witch there is millions of options for mowing the swathe ability is ripe for a first ever non macdon swath option i see real pictures of the JD W260 with a grain header working a field when i googled for a fs25 JD swathe vehicle.
This might come in a future update but I don’t have a timeline for if or when that might be. I apologize. I encourage you to look into modifications to your favorite maps to allow for mowing of other crops like wheat. Plenty of W235 and W260s out there using the disk head to mow crops for silage. Although you don’t have the width, you can typically cut faster with the disk mower so in my opinion it evens out. You also don’t get a crimp on the crop to help it dry down with a draper. There are advantages of both. Perhaps some day I’ll add that option.