Mineral Supplementation in Lambs

It is that time of year again when lambs are weaned and lamb performance takes a nose dive on many farms. What causes the drop-off in performance and is mineral supplementation the answer? Michael Gottstein Head of Sheep Knowledge Transfer Department, Teagasc, discusses this complicated subject
Lamb performance is affected by many different factors, the main ones being; nutrition, dry matter intake, weather, general health status, parasite burden, absence of lameness etc. Of course minerals can play a role in some of these factors.
The whole area of mineral deficiency and supplementation is very complicated as there are interactions between minerals and also differences in the availability of minerals depending on the compound in which the mineral is delivered.
Cobalt and other minerals
The main minerals that are of concern from a sheep point of view are Calcium, Magnesium, Cobalt, Copper, Iodine and Selenium. However on most Irish lowland sheep farms the mineral that is most frequently found lacking in lamb diets is Cobalt. Extreme care should be taken if supplementing with other minerals as excess supplementation of minerals such as copper and selenium can lead to toxicity in sheep.
Unless there is strong evidence (laboratory blood sample results etc.) to show the need for supplementing other minerals, lamb mineral supplementation should revolve around cobalt. It is my opinion that supplements should be either ionic cobalt or cobalt sulphate based in the absence of manufactures evidence of rumen availability of other cobalt based compounds. The reason for this is that the cobalt being supplemented needs to be available in the rumen to the bugs which use it to manufacture Vitamin B12.
Ways of supplementing minerals
In addition to the type of compound being supplemented there are also many different mechanisms of supplementing minerals. Mineral supplementation can be given:
- orally as a drench,
- in a lick bucket,
- in concentrate feed,
- as a bolus and
- dissolved in drinking water.
The latter is an unreliable method as grass-fed sheep will drink very little water and virtually no water during wet weather.
Mineral supplementation costs
The costs associated with mineral supplementation vary largely depending on the type of minerals being supplemented and also the mechanism used to supplement it. In general, using concentrate feed to carry minerals is the highest cost, followed by mineral lick buckets, boluses and then oral drenches.
When considering the options, keep in mind that lambs need a regular supply of cobalt to enable the bugs to manufacture Vitamin B12. In effect it means we need a regular supply of cobalt in the rumen (probably every two weeks). So if using a drench it would need to be given every two weeks.
Assessing the benefit
If you are spending money on mineral supplementation then it is important to make sure that you are getting a benefit from that expenditure. The simplest way to verify if a particular mineral supplement is working on your farm is to treat a group of sheep and compare their performance to an untreated group. If the particular mineral deficiency is causing production loss on your farm and the mineral supplement is correcting that, then you should be able to see improved performance.
To do this, select 50 similar sheep and treat and mark every second sheep with the mineral supplement. The 25 untreated sheep are your control group. These also need to be identified. Run the group of sheep together and monitor the performance of both groups. The performance of the treated group need to be large enough to not only cover the cost of the mineral supplement, but also needs to cover the cost of the labour associated with giving the supplement.
If you missed the Teagasc Sheep Open Day in Athenry recently you might like to look back on it here at Looking back on Teagasc Sheep Open Day and Booklet 2022
The Teagasc Sheep Specialists and advisors issue an article on a topic of interest to sheep farmers on Tuesdays here on Teagasc Daily. Find more on Teagasc Sheep here