Im a new owner of L2501 also, and I feel need to clarify based on the other posts so far.
What you are supposed to do in this tractor is change the oil and 3 filters at 50 hours. So you will be replacing the Oil Filter, Hydraulic oil filter, and transmission oil filter. You will also change the engine Oil at this time. The owners manual does not call for changing the transmission/hydraulic oil at 50 hours, but I've often heard people suggest changing it as well at 50 hours. The only thing the manual calls for at 10 hours is to grease your loader zerks and 3 point hitch zerks with good grease. You should do this EVERY 10 hours, and you grease until you see it begin to overflow.
The reason you do this first service so early is to remove any tiny metal particles or shavings that can be generated from brand new gears breaking in for the first time. If you can imagine lots of new metal gear parts freshly cut and machined and then being put under load for the first time - you get some tiny particles, shavings, etc as the tractor begins to be used for the first time as parts get used to one another. This first service is to flush all that "new wear debris" from the system so that it doesnt cause issues.
The owners manual also suggests not to run the tractor at wide open throttle in the first 50 hours. This is more a precautionary suggestion to simply take it a little easy on the tractor as it undergoes this "break in" period. Just something to keep in mind. Dont run the RPM's at wide open for long periods in this first 50 hours, just to be on the safe side. Also make sure to check your radiator pre filter very often. This is a simple screen filter that just slides out, yo ucan blow it out, then slide it back in. Very important this pre filter stays clear of debris at all times.
If you dont hae it, here is the L2501 owners manual. You shold take some time and read it over thoroughly as it contains a lot of info:
https://kubota.ca/getmedia/1e3d2402-3033-431b-a5bb-e8e115247ab9/L2501-OPS-EN-TC55019711?ext=.pdf