The story Behind Cobalt in Sheep

 blog cobalt deficiency
What is Cobalt and why does Sheep need it?

Cobalt is required in all ruminants’ diets solely for the synthesis of vitamin B12. In other words, sheep require vitamin B12, not cobalt to function.

Now you are wondering “What is Vitamin B12 used for?” Vitamin B12 plays a huge role in the everyday functioning of a ruminant’s body as it is needed for the metabolism of energy and the production of red blood cells. The vitamin  is stored in the liver, and also has a role in wool and body growth in sheep.

Vitamin B12 can be purchased solely as an injection and will give an instant effect. However the cost of the injection often does not match many farmers budget with large doses required and this where cobalt comes into play.

Cobalt actually plays a biological role in the rumen, manufacturing vitamin B12 with the help from micro-organisms inexpensively as cobalt is a constituent of vitamin B12. A lack of cobalt in the diet often can be caused by soil cobalt levels.

Interestingly, soil pH, soil compaction and rapidly growing pastures can affect cobalt uptake through the grass in which the animals are eating. Cobalt levels in a pasture will decrease if soil pH rises, while high molybdenum levels in a soil can also induce cobalt deficiency.

How Will a Deficiency in Vitamin B12 Affect your Flock?

Sheep tend to lose their appetite as well as having a poor coat of wool and body condition. These symptoms would most commonly be seen in weaned lambs during late Summer and Autumn when out on pasture.

However, symptoms don’t stop there! Weeping eyes, failure to thrive, scabby ears and anaemia are also signing of a lack of vitamin B12 in lambs while ewes can experience infertility and poor mothering ability, although it is quite uncommon.

How can I test to prove a deficiency in Cobalt?

Thankfully, there are a handful of tests in which can be carried out to see if it actually is a deficiency in cobalt that is your issue on your farm.

Firstly, the most direct way of testing is taking a blood sample from your animal. A blood test for cobalt measures the level of an enzyme called methylmalonic acid, which will increase whenever the level of vitamin B12 is low.

A pasture test is another method to determine that your fields are low in cobalt. However, regular pasture tests don’t routinely check for cobalt as it’s not an essential nutrient for plants to grow but can be included on request. In a pasture test, you are aiming for cobalt levels above 0.04 parts per million (ppm) to avoid being in a deficit.

Lastly, a home test can be carried out if you suspect a deficiency on your farm. This can be carried out by injecting a fraction of a batch with injectable vitamin B12 and comparing their liveweight gains in two weeks’ time to those animals that weren’t treated.

How do you Combat Cobalt Deficiency?

Sheep has an extremely limited capacity to store vitamin B12, meaning that sheep need continuous supply of cobalt to avoid deficiency. The simplest way of ensuring sheep has a continuous supply of cobalt is through their diet.

Interestingly, your pasture species will determine cobalt concentration with clover having higher cobalt levels than ryegrass species.

Cereals also have low levels of cobalt, particularly grain, so don’t forget to supplement your flock with cobalt if they are on a high meal diet.

Soil Cobalt Levels

As I already mentioned, soil cobalt levels can result in a deficiency in vitamin B12 and is affected by the soil pH, soil compaction and rapidly growing pastures. So, how can you overcome low levels of cobalt in your soil? Thankfully, there is a solution.

Cobalt can be added by spraying on the pasture or by including in into your fertiliser. However, be mindful of not adding cobalt to your pasture too soon after liming, as the alkaline pH will limit your cobalt availability.

As well as that, testing your soil to see your iron and manganese levels can give you an indication as to why your soil in low in cobalt as iron and manganese will decrease cobalt availability and inhibit uptake.


Vitamin B12 injections are another option in combatting vitamin B12 deficiency, providing the quickest response. A single injection should prevent a deficiency of the vitamin for approximately 6-8 weeks. However, large doses are needed to make a difference in the long term, and with large doses comes large expenses!


Boluses is the ideal solution for cobalt deficiency, slowly releasing the mineral (and possibly other minerals) in the reticulum continuously over a longer period of time. The slow releasing cobalt is ideal for sheep due to their limited capacity for storing vitamin B12. Our two biggest selling cobalt boluses are the cobalt 12 and Cobalt Master.

However, often the boluses prove expensive for giving to those lambs which only require supplementation for two to three months. But the cobalt boluses are the ideal method of supplementing sheep intended to be on the farm long term.


Another method of supplementing cobalt is oral drench which is favoured by many farmers. Cobalt in drench form is the cheapest method of supplementing the mineral but unfortunately will only last a maximum of three weeks, adding to the workload of your flock.

Nonetheless, this has a huge financial benefit for weaned lambs that are only intended to be kept on your farm for a few months, while it is advised to give ewes and lambs intended to be kept on the farm a long term supplement such as boluses. The most popular drenches sold are Growvite and Cobalt B12, which also cover other minerals.

However, the latest invention of anthelminthic containing cobalt has been put on the market and is proving popular, completing two jobs in the one saving lots of valuable time for you busy farmers! However, be weary as the principle group of anthelmintics that is combined with cobalt is 1-BZ, the white drenches, which has the highest resistance level of the drench types with 80% of Irish farmers having 1-BZ resistance.

Dosing lambs from around three months of age is advised.

Lick Buckets

And lastly, I left the solution that is going to require the least effort to last; lick buckets. Again, anything that is too good to be true, generally is too good to be true.

Giving free access minerals to your flock is unfortunately not a reliable method of supplementing minerals due to intake varying throughout the entire flock with some lambs receiving no intake.


Author: is based in Ballyconnell Co Cavan.The company was established in 1991 and is a family run business serving the Agri needs and requirements in the west Cavan area.Agridirect aim is to provide our offering of Agri products at a competitive price anywhere in the country- giving you the convenience of buying from your home.

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