Just a note - the anthrax attacks will cause relatively limited damage. Culling of the infected herds, burning/burying carcasses and perhaps the fields where the spores landed, and declaring them off limits for grazing for some time will do it. Unlike plague, anthrax does not spread directly from one infected animal/person to the next, or via an intermediary like rat/flea. Of course the evidence of the balloons will make the US even more pissed off, and you'll see the USA institute aerial patrols along the Pacific Northwest and Mountain States to spot and shoot down balloons - if they are shot down before cargoes released, the area of contamination can be contained.
FWIW the decrease in available meat for the USA due to this will be relatively limited - this serves no purpose. At least the L.A. attack had a theory of causing panic/fear, this attack won't hurt very many people (a few may die) and won't affect the food supply in a serious way and the Japanese should have known this. The L.A. attack shows a complete misunderstanding about the USA even after 3 years of war, this is so out of la-la land.
When the Germans hear of this, folks like Runstedt are going to realize that the gloves are now off and that the allied response to use of gas by the Germans will be horrific beyond belief. Adolf of course will ignore this, but all but the most dedicated SS and Nazi types will realize that unless something is done right now Germany will cease to exist as a nation at all, and the civilian death toll will be unreal.