Horses that are bred for racing are referred to as bloodstock.
bloodstock in British English
(ˈblʌdˌstɒk)
noun
thoroughbred horses, esp those bred for racing
bloodstock in American English
(ˈblʌdˌstɑk)
noun
Thoroughbred horses collectively
Word origin
? < ( blooded (sense 2)) + stock
Examples of 'bloodstock' in a sentence
bloodstock
That proves what good judges all us trainers and bloodstock agents are!
The Sun (2015)
The rest of the bloodstock industry would follow.
Times, Sunday Times (2009)
It has property and bloodstock interests.
Times, Sunday Times (2016)
In peacetime he pursued the loves of his life, going into the bloodstock industry and breeding some notable champions and founding his own aviation company.
Patrick Bishop FIGHTER BOYS: Saving Britain 1940 (2003)