Supplementation of Vitamin B12 in Cattle and Sheep to Prevent Deficiency

Interestingly, cattle and sheep may need supplementation with B12. In a way it makes sense; if people can’t get B12 through fruit and veg anymore because of our farming ways, how are especially factory farm animals going to get their B12? Well, just like us: through a supplement. Which makes the B12-reason to eat animal products somewhat invalid.

B12 injection, cattle and sheep may need it too.

B12 injections, cattle and sheep may get them too.

Original article: Vitamin B12 deficiency , source: Ancare

Vitamin B12 Deficiency in animals is the end result of insufficient Cobalt intake. Cobalt is acquired from the pasture and soil as animals feed and is used to make Vitamin B12 by micro-organisms with the rumen (2nd stomach). Vitamin B12 is then absorbed in the small intestine and transported throughout the body by the blood, with excess being stored in the liver. A female animal will provide B12 to a growing foetus, but will not supply any of the vitamin in its milk.

The amount of Cobalt available to animals varies as a result of several different factors. The amount of Cobalt occurring naturally in the soil varies according to the type of rock from which the soil is derived. The amount then available for uptake by the pasture is influenced by the presence of other minerals (e.g. Manganese) and supplements (e.g. lime), which can bind the Cobalt in the soil and prevent its absorption by plants.

Rainfall can also play a major role, with high rainfall leading to leaching of Cobalt from the topsoil into the lower soil layers. This can be seen as a seasonal effect where rainfall is concentrated at one time of the year.

The type and condition of the pasture can also pay a major role. In general, grasses take up less Cobalt than legumes and lush, fast-growing pastures absorb Cobalt at a lower rate than slower growing pastures.

These factors mean that coastal areas are particularly prone to Cobalt deficiency and the deficiency has been well documented in coastal southern Australia. Cobalt deficiency has, however, also been identified in many inland parts of Australia.

Vitamin B12 is essential for cell growth and maturation, energy production and wool growth. In general, sheep are more susceptible to Vitamin B12 deficiency than cattle are. Rapidly growing animals (i.e. lambs/calves and weavers) are most likely to develop a B12 deficiency and will suffer most badly when a deficiency develops. 

Clinical signs of Vitamin B12 deficiency include weight loss, suppressed appetite, decreased feed efficiency, anaemia, diarrhoea, rough coat, scaly ears and weepy eyes. These signs may occur in different combinations and the clinical picture is often not very clear. In many cases B12 deficiency manifests as a wasting disease and, in severe cases, the mortality rate may be high. Like most diseases, however, far greater economic losses result from undetected subclinical disease causing reduced production than from clinical outbreaks. Vitamin B12 deficiency can lead to reduced fertility, lower birth rates and birth weights, reduced growth rates, and reduced wool growth and wool quality.

Vitamin B12 deficiency also impairs the immune function of animals so that they are more likely to acquire infectious diseases and will suffer worse when infected. Animals that are deficient in B12 are likely to carry a higher worm burden than they otherwise would. The high worm burden causes scours and damage to the wall of the intestine so that less B12 is absorbed in the gut and the immune system is suppressed even further. Thus, a vicious circle leading to severe disease is created.

It is important to remember that the animals that are most susceptible to Vitamin B12 deficiency are also those that are most susceptible to infection with worms. Good worm control allows animals to make best use of the Cobalt that is available in the environment and prevents worm populations from taking advantage of an animal’s depressed immune system. Prevention of Vitamin B12 deficiency allows animals to withstand worms better and minimises the required frequency of drenching. B12 also helps in the repair of damage after a worm burden has been removed. It is therefore good practice to consider treatment programmes for the two diseases together rather than in isolation.

Prevention or treatment of B12 deficiency is best achieved by providing a Vitamin B12 supplement directly to the animals. It is important to know the level of deficiency to determine the frequency with which animals may require supplementation. The level of Vitamin B12 deficiency can be assessed easily using a blood test. In cases where subclinical deficiencies are suspected, at least 10 individuals from the most susceptible class of animal should be tested at the most critical time of the year.

In areas where the Vitamin B12 deficiency is marginal, treatment of the susceptible causes of animals (i.e. lambs, calves and pregnant animals) may be sufficient to prevent problems and minimise production losses. In areas with severe deficiency problems, treatment of all animals may be required on an ongoing basis.

Is is good practice to provide all animals entering a feedlot with a B12 supplement as part of their induction programme. In cases of even marginal deficiency, the B12 will enhance the animals’ appetite, getting them onto feed quicker and providing better feed efficiency and improved weight gains (as demonstrated by the 17kg weight advantage in below graph – for graph, please see .pdf file at top of page)


  1. ” if people can’t get B12 through fruit and veg anymore because of our farming ways”
    People can’t get enough B12 from fruit and vegetables because fruit and vegetable don’t contain enough B12. it’s nothing to do with how we farm them. Sustainable, organic fruit n veg doesn’t contain enough B12. Even blackberries gathered from the wild don’t contain enough B12.
    We need supplements.

    The article contains a very nice graph (click on the the link above or go to and scroll to the bottom) which appears to show that vitamin B12 injections for animals are utterly pointless (there’s no difference bewteen the 3 different injections used or the control group – animals which didn’t get a B12 injection)!

    • Hi Ian, thank you for reading and taking the time to reply :-)
      The graph refers to weight gain, I’m not sure what you think it refers to?
      B12 is produced by bacteria that live in soil and ends up in the gut of animals who eat from the land (including us). There they keep producing B12. The reason I posted this article is because it points out that animals need to be supplemented with B12, which means they can’t get it through their food either. And if they can’t, then eating animals for B12 is not a valid reason anymore. That was my logic 😉

      • Hey so just curious on this: it would make sense through this logic not to eat cows for b-12 because they are being injected. But what about oysters? I’m fairly sure they aren’t injecting oysters with b-12 and they are suppose to be a pretty good source. Just wondering what your thoughts would be toward this?

        • Hi JH, thanks for your message :-)
          My reply to your post, is that I don’t particularly care about oysters being a good source of B12, as I don’t eat any animals 😉 Not sure what I could say; I can’t argue with what is a source of what, and certain animals products just are a good source of B12. My thoughts are; leave them alone :-)

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