I was curious about the destination of manufactured supplemental B12 (I am vegan).
In several books promoting vegan or plant-based diets I had come across the claim that 90% of B12 supplements are fed to livestock. This figure seemed quite high to me. The usual reference for this claim is not a scientific paper, research study or industry analysis but is a quote from one Dr. Jennifer Rooke in a local newspaper. Rooke is an "Assistant Professor in the Department of Community Health and Preventive Medicine at Morehouse School of Medicine. ". It is clear from reading her other articles on the site that she promotes plant-based diets, so we can understand where she will be coming from on the issue and need to be particularly wary of bias in that respect.
The statement reads:
"In order to maintain meat a source of B12 the meat industry now adds it to animal feed, 90% of B12 supplements produced in the world are fed to livestock."
ref : baltimorepostexaminer.com/c...
The claim is not referenced and I found no source which corroborated it. Organisations promoting ruminant agriculture strongly reject the claim and say that such supplementation is rare and it is Cobalt which is added to the soil (only when needed) to allow natural ruminant manufacture of B12 in their stomachs.
ref : praisetheruminant.com/rumin...
Another animal agriculture source had this to say:
"In animal nutrition, cobalt plays a central role as the core of vitamin B12. Thus, as plants do not provide sufficient vitamin B12 or cobalt, we routinely supply monogastric animals (poultry and pigs) with vitamin B12 as part of their regular vitamin and trace mineral premix."
"Ruminants are routinely supplied with cobalt to aid synthesis of vitamin B12, by bacteria in the rumen. This is needed for bacterial growth per se because these bacteria are central in ruminant nutrition physiology. Later on, such bacterial B12 is absorbed by the animal, covering its needs"
"Cobalt compounds used in animal nutrition are known biohazard materials at high concentrations, such as those used in premix plants. Thus, they should be handled with protective equipment because cobalt is a skin irritant and carcinogenic through inhalation. The use of cobalt, however, is still allowed in the European Union for ruminants, horses and rabbits, but in restricted concentrations. The same is true for the rest of the world, where cobalt is supplied often 10 times higher than requirements in all feeds for ruminants."
feedstrategy.com/blogs/feed...
I dug around further and found this resource which seems fairly neutral (an encyclopedia with no "skin in the game", so to speak):
Vitamins. Ullmann’s Encyclopedia of Industrial Chemistry.
With reference to the pure substance, the total sales of vitamin B12 amount to more than 10 t/a and the market volume is ca. 77×106. The feed sector accounts for ca. 55 % of the sales, and the food/pharmaceutical sector for ca. 45 %.
from
sci-hub.st/https://onlineli...
So it seems the 90% claim for B12 supplementation to animals is bunk and the real figure is closer to 55% of supplemental B12 going to livestock, not an insignificant amount to be sure, but much less than that claimed by many vegan sources. However, it appears cobalt supplementation is quite widespread in animal agriculture, with the "feed strategy" animal agriculture source above claiming that supplemental cobalt is supplied in significant quantities in "all feeds for ruminants".
So my takeaway is that many farmed animals receive supplementation in their feed that enables them to produce adequate B12, but in many cases this supplement is Cobalt rather than direct supplemental B12, although most manufactured supplemental B12 (~ 55%) does go to farmed animals.