For a bit more detail in your email, you can do, e.g., the following
( echo "Subject: Dump completed";
echo "Backup of $DBS";
echo "completed on `hostname` at $BACKUP/$NOW" ) | mail -t email@example.com
The statements in the parentheses become a subprocess in the script whose output is piped to the mail command. That allows you to fill out the Subject (and other headers if you want) plus some informational content in the body of the message.