Sheep producers can be forgiven for administering mineral supplementation when it may not be warranted. The whole area is big business in all livestock systems and there is a wide array of products on the market and big sums spent on marketing them. There are certain instances where mineral supplementation is vital and there are times where their use is a waste of money. Information on assessing whether mineral supplementation is an area you should be doing more about can be found here.
There is generally merit with a significant percentage of flocks in administering cobalt supplementation to prevent cobalt deficiency. This is an area where significant research has been carried out in in recent years. Issues typically start to emerge from the end of July onwards, but this can differ depending on the mineral status on-farm.
Characteristic signs start with lambs performing below target or losing condition despite on a relatively good level of nutrition, while common signs of advanced problems are lambs starting to pine away, going dry in the wool and in some cases, experiencing the skin on their ears becoming scaly or scabby with skin flaking away.
Veterinary advice highlights that lambs require about 1mg cobalt per head per day. Sheep do not have the ability to store cobalt and therefore supplementation will be required typically every two weeks where administering an oral drench. Other options include administering boluses or feeding meal with an adequate mineral inclusion level. Adding cobalt to water may also be an option, but in this scenario, you need to be confident lambs will be drinking regularly.