The Hair And Fur render element produces an additional image that depicts only the elements in the scene generated by the Hair And Fur modifier. This image can be used for compositing.
Main toolbar > (Render Setup) > Render Elements panel > Add button > Render Elements dialog > Hair And Fur
Rendering menu > Render Setup > Render Elements panel > Add button > Render Elements dialog > Hair And Fur
Note: The Hair And Fur render element supports only the ”buffer” rendering method using the default scanline and mental ray renderers.