Sending horses to Canada or Mexico for slaughter would have made more economic sense than taking care of them after they were no longer 'profitable.'

From the Paulick Report via Forbes:
Perhaps best known for his work on the Michael Jackson estate, Tax
Court Judge Mark Holmes is often regarded as eloquent in his
appraisal of cases before him.
However, when creating a bench opinion on the case of Joseph G.
Bucci, his writing became a bit uncouth. Bucci, the owner of
American Rock Salt, was facing tax and accuracy penalties of
$711,980 for 2016 and 2017, mainly in reference to his Thoroughbred
racing and breeding business, which the IRS had deemed a hobby
rather than a business.
Judge Holmes sided with the IRS at Bucci’s hearing, at which Bucci
represented himself. Though Judge Holmes commended Bucci on his
founding of American Rock Salt, his main focus was that Bucci chose
to house his retired racehorses on his property when they were done
racing and being “profitable.”
Judge Holmes noted that sending the horses to Canada or Mexico for
slaughter would have made more economic sense in Bucci’s case.
Judge Holmes noted that sending the horses to Canada or Mexico for
slaughter would have made more economic sense in Bucci’s case. He
said that most racehorse owners who have horses that are incapable
of racing will find a way to get their horses to Canada or Mexico
for slaughter or “glue factories” (slaughter is legal in both Canada
and Mexico).
However, it is evident that “most” racehorse owners do not export
their horses for slaughter—or glue factories, of which very few
use any equine body parts to make glue today. Many industry players
stand in solidarity against equine slaughter, including The Jockey
Club, the Thoroughbred Owners and Breeders Association, and the New
York Racing Association, among others.
Many tracks, including Delta Downs and Evangeline Down, owned by
Boyd Gaming, have written rules to punish those who send horses to
slaughter by permanently denying the owner or trainer stalls at
their tracks.