





Now Playing: Watch horse break free on Kentucky highway
Now Playing: Quarter horse event returns to Oklahoma amid pandemic
Now Playing: German Shepherd and horse pose for adorable photo shoot
Now Playing: Trainer Bob Baffert suspended after Derby winner’s positive drug test
Now Playing: Food expert: Americans buy food for convenience, not for health
Now Playing: The Rundown: Top headlines today: Aug. 23, 2021
Now Playing: By the Numbers: Pfizer’s road to vaccine approval
Now Playing: Tennessee emergency official: ‘Devastation is hard to fathom’
Now Playing: CDC chief on FDA’s Pfizer approval: ‘This is a very powerful signal of safety’
Now Playing: Dad fatally shot while driving 2 sons
Now Playing: Cuomo hours from leaving office
Now Playing: Rev. Jesse Jackson, wife Jacqueline responding to COVID-19 treatment
Now Playing: Henri continues to wallop New England
Now Playing: Flooding decimates Tennessee, at least 21 dead
Now Playing: Will US extend Afghanistan evacuation deadline?
Now Playing: Pfizer vaccine gets full approval from FDA
Now Playing: Schools looking at ways to address mental health
Now Playing: The Breakdown: Pfizer CEO reacts after COVID vaccine receives full FDA approval
Now Playing: Biden encourages companies to mandate vaccinations after FDA approval