This dialog is used to add or change any "reasons" that are set up for entering an animal into the herd database. You get to this dialog from the Animal Details View on the In/Out page. Press the "..." button next to the "How?" list.
The dialog shows a list of current reasons. To add a new one, click on the New button, and then type in the reason and description. To edit an existing one, select it in the list, and then type in the reason and description. To delete one, select it, and click on the Del button.