Go to "General" - "Cause".
In "Cause" you can set up codes and names for causes in the bottom at the empty column. You can't duplicate codes. The cause must be set as "active" or "new" to be applied.
To the right there are many optional columns to set checkmarks. In the top the animal type are are listed. If you are creating fx a death cause for weaners, you set a checkmark below "Used as progeny" - "Death reason".
Next time you are registrating dead weaners, you are able to select the cause.
If you don't use a cause anymore, you can set it as "Passive" below "Status". Then it is no longer available, but you can still see the cause for previous registrations. You can always set is as "Active" again.