Normally if we put the forwarder from DNSMGMT.MSC, those are static forwarder.

Those are not replicated to all DCs and there is no any GUI option in 2003 for creating the AD integrated forwarder. 

How to create AD integrated forwarder on Windows 2003? 

dnscmd /ZoneAdd sanc.com /DsForwarder 10.1.2.4

http://msmvps.com/blogs/ulfbsimonweidner/archive/2006/09/30/DNS-Conditional-Forwarders-_2D00_-AD-integrated.aspx

Find the below Screenshots:



How to create AD integrated forwarder in Windows 2008, 2008 R2, 2012 , 2012 R2 ? GUI is available in Windows 2008, 2008 R2, 2012 , 2012 R2


     

Normally forwarders are non ADI data so those are not replicated with other Name servers. Here come into play the ADI forwarders. ADI forwarders are replicated with all other name server. You need to create it once in your domain/forest & those will be replicated all other name servers.




You can also delete an AD integrated conditional forwarder using the following command.
(GUI is available in 2008 & higher version OS)

dnscmd dnsserver /zonedelete domain.com /DsDel /f

___________________________________________