Like many Linux utilities not included on Mac OS X, Homebrew can provide logrotate to more effectively manage large log files. Setup:
brew install logrotate
/usr/loca/sbin/logrotate -f -s logrotate.status logrotate.conf
Note that in the above, I defined explicitly where to stick the logrotate status file so that it is owned by the current user and not reliant on sudo, etc.