**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** THE STANDARDBRED RACING INDUSTRY IS CONSTANTLY WORKING TO PRODUCE FASTER, BETTER PERFORMING HORSES. AS PERFORMANCE INCREASES OVER GENERATIONS, THE INDUSTRY ALSO SEES INCREASES IN THE OCCURRENCE OF SEVERAL DISEASES THAT IMPACT THE WELFARE OF THESE HORSES. THESE INCLUDE OSTEOCHONDROSIS (A CONDITION AFFECTING THE CARTILAGE AND BONE IN JOINTS), RECURRENT EXERTIONAL RHABDOMYOLYSIS (A CONDITION RESULTING IN PAINFUL MUSCLE CONTRACTIONS), AND CARDIAC ARRHYTHMIAS (ABNORMAL HEARTBEATS THAT CAN LEAD TO DEATH). AS THE OCCURRENCE OF THESE DISEASES INCREASE, SO DO THE NUMBER OF RACETRACK BREAKDOWNS, INJURIES, AND SUDDEN CARDIAC DEATHS--ALL OF WHICH ARE WELFARE AND SAFETY ISSUES FOR THE HORSES AND PEOPLE INVOLVED. PREVIOUS WORK AND INDUSTRY KNOWLEDGE SUGGESTS THAT THESE DISEASES OCCUR MORE OFTEN IN TOP PERFORMING STANDARDBREDS. THIS SUGGESTS THAT WHILE BREEDERS ARE ATTEMPTING TO IMPROVE PERFORMANCE, THEY MAY ALSO BE ACCIDENTALLY BREEDING FOR DISEASE. THE STANDARDBRED RACING INDUSTRY NEEDS ACCURATE INFORMATION REGARDING THE RELATIONSHIPS BETWEEN DISEASE AND PERFORMANCE AND TOOLS THAT WILL ALLOW BREEDERS TO EFFECTIVELY BREED FOR PERFORMANCE AND AWAY FROM DISEASE.THIS PROJECT WILL UTILIZE DISEASE DIAGNOSIS, GENETIC DATA, AND PERFORMANCE DATA FROM MORE THAN3,000 STANDARDBRED RACEHORSES TO ACCOMPLISH THREE GOALS. IN THE FIRST OBJECTIVE, WE WILL ADDRESS THE INDUSTRY'S NEED FOR ACCURATE INFORMATION BY DETERMINING THE RELATIONSHIP BETWEEN EACH DISEASE (OSTEOCHONDROSIS, RECURRENT EXERTIONAL RHABDOMYOLYSIS, AND CARDIAC ARRHYTHMIAS) AND 33 PERFORMANCE TRAITS. THE SECOND OBJECTIVE OF THIS PROJECT WILL DETERMINE THE GENETIC ARCHITECTURE AND HERITABILITY FOR THE 33 PERFORMANCE TRAITS. THE HERITABILITY AND GENETIC ARCHITECTURE OF EACH TRAIT WILL PROVIDE INFORMATION ABOUT WHETHER THAT TRAIT CAN BE PASSED FROM GENERATION TO GENERATION AND HOW THE UNDERLYING GENETICS LEADS TO SAID TRAIT. THE TRAITS THAT ARE DETERMINED TO BE MODERATELY TO HIGHLY HERITABLE WILL THEN BE USED IN OUR THIRD OBJECTIVE WHERE WE WILL DEVELOP PREDICTION TOOLS THAT WILL BE USED BY BREEDERS TO PREDICT PERFORMANCE ABILITY. THESE TOOLS WILL BE DEVELOPED USING GENETIC LOCI THAT ARE ASSOCIATED WITH, AND PREDICTIVE OF, EACH OF THE MODERATE TO HIGHLY HERITABLE PERFORMANCE TRAITS. THE DEVELOPMENT OF TOOLS TO DETERMINE A STANDARDBREDS RISK FOR OSTEOCHONDROSIS, RECURRENT EXERTIONAL RHABDOMYOLYSIS, AND CARDIAC ARRHYTHMIA ARE CURRENTLY UNDERWAY. UPON COMPLETION OF THIS WORK, THE COMBINED USE OF THE PREDICTION TOOLS FOR PERFORMANCE, RER, OC AND ARRHYTHMIAS, WILL ALLOW STANDARDBRED OWNERS, BREEDERS, AND TRAINERS TO SELECT FOR ELITE PERFORMANCE WHILE SELECTING AWAY FROM DISEASE.