All of the reputable information I can find, in addition to the advice of literally every vet I've ever worked with over the last 20 years, says "yes." What rep

All of the reputable information I can find, in addition to the advice of literally every vet I've ever worked with over the last 20 years, says "yes." What reputable source (not something like "naturalnews.com") do you have that says that this is unnecessary and dangerous?