Keiba History & Racehorse Welfare Experts or Resource Links Needed

Looking for sources on keiba history & welfare practices I'm seeking out information regarding keiba history, specifically the old and current welfare practices for race horses (their treatment during career and retirement, controversy around enthusiastion, etc.) Additionally, if anyone could link sites that discuss and teach keiba history (like the old https://horsejpkeiba.com/ before it was taken down), that'd be great. They can be English or Japanese, preferably English.