The report is expected by March 1 next year.
The request is contained in an agriculture-related bill which has passed both the United States Senate and the House of Representatives.
The office has been asked to look at how the horse industry has responded to the closure of US horse slaughter facilities, exploring any effects on the number of horse sales, exports, adoptions and abandonments.
It has been asked to investigate the implications any changes have had on farmers' incomes and trade, and the extent to which horses in the US are slaughtered for any purpose.
It will also probe impacts on state, local governments and animal welfare organisations.
The bill will now go to the president for his expected sign-off.