A portion of proceeds from documentary filmmakers John and Brad Hennegan’s The First Saturday in May will benefit the Grayson-Jockey Club Research Foundation for equine research.

The Hennegan brothers have pledged 25% of box office revenue and DVD revenue to the Grayson-Jockey Club. The announcement was made prior to a screening of the film at the Symposium on Racing and Gaming in Tucson, Arizona.

The film profiles the journeys of six trainers on the way to the 2006 Kentucky Derby Presented by Yum! Brands (G1). The film debuted at Robert DeNiro’s Tribeca Film Festival in New York City and since has been shown at several film festivals. The film earned the Best Documentary award and the HBO Films Producer Award at the Savannah Film Festival.

The First Saturday in May tentatively is scheduled to be released in theaters the week of April 25, 2008. More information about the film is available here.