You can use the test  run webhook to initiate a load test by adding a section like this to your .travis.yml file:

    - <a href="{{test">{{test</a> id}}/token/{{ test run token}}/run

You can also tell travis to only send the webhook when your build succeeds (or fails) by adding something like this:

on_success: always
on_failure: never

Check out the  TravisCI docs for more details.