This is so weird and disturbing that you have to read it for yourself because otherwise you wouldn't believe this stuff could have been proposed seriously.
Once the man in the street got wind of it, of course they batted it down in the court of public opinion very rapidly and plans were scrapped. This was intended to be a kind of widespread practice alongside assembly line vaccines for kids in the 1950's. The average person has enough good sense to know something was seriously wrong with the notion of branding children with their blood type so they could provide or receive blood transfusions after they dropped the bomb.
I read an essay by some guy a while back, can't remember where, who suggested this was part of the disinfo campaign to put people off civil defense programs by associating them with horrors like these. Once you could create associations between civil defense and cattle brands for kids you could begin to terminate all civil defense programs for the public with little opposition. Of course civil defense is in reality all about protecting children from the horrors of war, not subjecting them to horrors in peacetime.