Scottish Racing has warned the sport is "not sustainable" due to greater revenue losses amid the new lockdown.
The governing body had budgeted for a £12m loss in the 2020-21 financial year with races held behind closed doors.
But Scottish Racing manager Delly Innes says the closure of further revenue streams brings more financial problems.
"Before the second lockdown, [the five] Scottish racecourses have lost £12m, which is 55% of their income, just through no ticket sales," she said.
"That has a knock-on effect to other areas of the industry. Now we are seeing the closure of all betting shops, which means we've lost another source of income as racing sells footage and data to them.
"For example, revenue at Musselburgh on New Year's Day was down £250,000.
"With this reduced income and still having to pay our overheads, it's not sustainable while we're racing for zero profit."
The Scottish government has made £2m available to horse racing in Scotland as part of a £50m funding package for sport. And Innes says while that has been "vital", the focus for racing is simply to survive.
"The grant funding was not only welcome but vital to bridge the gap until it is safe for spectators to return to racecourses," she told BBC Radio Scotland.
"But we do have to make sure we have a Scottish horse racing industry to come back to when crowds return.
"The fact we've been able to continuing racing behind closed doors has been essential, but the second lockdown puts additional pressures on the racecourses in many other ways."