DAIRY CATTLE PRODUCTIVE LIFESPAN (HOW LONG DAIRY COWS SHOULD STAY IN THE HERD) IS A HOT TOPIC THAT IS HEAVILY DEBATED IN THE DAIRY INDUSTRY IN THE USA AND ABROAD.WHILE THERE IS THE IDEA AMONG SOME PEOPLE THAT DAIRY CATTLE SHOULD LIVE LONGER, A LONGER PRODUCTIVE LIFESPAN IS NOT NECESSARILY BETTER FOR FARM PROFITABILITY AND MAY ALSO NOT BE BETTER FOR THE ENVIRONMENTAL FOOTPRINT OF DAIRY PRODUCTS AND WELFARE OF DAIRY COWS. THERE REMAIN MANY OPEN-ENDED QUESTIONS AND MISCONCEPTIONS. THE OVERALL GOAL OF DISCOVER CONFERENCE 45 IS TO BRING TOGETHER LEADING SCIENTIFIC OPINION MAKERS IN THESE TOPICS AND CLARIFY HOW NEW KNOWLEDGE WILL, OR SHOULD, AFFECT PRODUCTIVE LIFESPAN. SPECIFIC OBJECTIVES OF THE CONFERENCE ARE: FIRST, PROVIDE A MEETING FOR RESEARCHERS, CONSULTANTS, AND DAIRY PRODUCERS TO HAVE IN-DEPTH DISCUSSIONS OF CUTTING-EDGE SCIENCE RELATED TO THE TOPIC OF DAIRY CATTLE LIFESPAN; SECOND, TO ADDRESS MISCONCEPTIONS ABOUT ANIMAL REPLACEMENT PRINCIPLES; THIRD, TO HIGHLIGHT OPPORTUNITIES IN RESEARCH, EXTENSION, AND TEACHING RELATED TO DAIRY PRODUCTIVE LIFESPAN. WE EXPECT THAT THE IMPACT OF THE CONFERENCE IS A GREATER UNDERSTANDING OF THE BIOLOGICAL, ECONOMICAL, AND SOCIETAL IMPLICATIONS OF DECISIONS THAT AFFECT DAIRY CATTLE PRODUCTIVE LIFESPAN.