There are plenty of tools available to move data from one Salesforce Org to another Salesforce Org. These tools can be used for Sandbox Seeding once the sandboxes are refreshed. This avoid manual data loading.
Check the below links for the tools to get data from one org to another org in Salesforce
Direct Download – https://www.sfapex.com/download/setup.exe
http://www.talend.com/download
I recommend SFApex tool. Awesome tool. Saves lot of time during migration. Easy to use and setup.
