We are load balancing LDAP through NetScaler. Is there a way to send actual client IP to DC instead of SNIP?

Wouldn't that be "Persistance" "Client-IP"?

Enabling USIP will insert the client IP https://docs.netscaler.com/en-us/citrix-adc/current-release/networking/ip-addressing/enabling-use-source-ip-mode.html

more options: https://support.citrix.com/external/article/CTX490460/enabling-netscaler-to-forward-original-c.html

i wouldn't enable USIP mode, as this overwrites SNIP mode. Instead I'd enable it with the service. USIP mode has a downside: The NetScaler fakes client's IP, so the server answers to the client. Because of this you need PBR on your switch or set the NetScaler as a default gateway on the server.