MANY sheep farmers will still be in the thick of lambing, but for those with growing lambs on the ground, the addition of trace elements could help boost daily liveweight gains and overall flock margins.
According to Liz Brown of Agrimin, growth rates can be reduced in lambs if their daily requirements for trace elements are not met and grazed grass, especially on sandier soils, can be low in many key trace elements.
“It is widely accepted that a poor trace element status in ewes can potentially cause a reduction in fertility or early lamb survival. However, it is not often appreciated that poor trace element status is associated with poor growth and health issues in lambs. 
Cobalt and Selenium play a key role in both lamb growth and health and therefore it is important that these requirements are met. 
She explains a constant supply of Cobalt, Iodine and Selenium are essential for optimal lamb growth. In the immediate post-natal period, lambs will receive maternal supplementation but this reduces soon after birth at which point dietary supply becomes more important. Grazing will often only supply low concentrations of these key trace elements meaning some form of supplementation could have a positive impact on performance. 
“Although there are many forms of supplementation available, the issue is ensuring that every lamb is adequately supplemented. Eroding boluses give each lamb a guaranteed level of supplementation to meet their daily requirement for optimal daily liveweight gain.
A farm study carried out at Lemmington Hill Head, in conjunction with Brian Dugdale, from Mole Country Stores, Alnwick, shows that offering the correct supplementation can optimize growth and profits. 
The farm has a flock of Aberfield ewes which lambed between mid-March and early May, with a  lambing percentage of around 180%.  
The study involved a group of just over 200 early-born lambs which were split into two groups. A control group of 100 lambs received no supplementation while the remaining group of 103 lambs were each given the trace element bolus 24·7 Smartrace® Lamb at the beginning of the period. 
All lambs were weighed at the start of the study, and then every four weeks until the study was completed at 108 days post bolusing. All lambs were grass fed over the period with no other form of trace element supplementation. 
The graph shows the difference in liveweight gain between the two groups. The bolused lambs grew, on average, 30% quicker than the control group, putting on an average of 3.56kg extra liveweight over the 108 day study period.  
“At £1.80/kg liveweight, this equated to an extra gain of £6.41 per lamb. With an initial investment in the bolus of 65p per lamb, the actual margin gain was £5.76/lamb.
“Other methods of trace element provision are available: buckets, drenches and powdered minerals. While buckets and powdered minerals are more convenient being offered ad lib, there is no guarantee that every animal is receiving their daily requirement, leading to variation in performance.
“While drenches are applied directly to each animal, they are only short lasting. Boluses on the other hand ensure supplementation to each animal over a longer period of time. A drench would have to be administered four times on a monthly basis to achieve the same length of cover as a single bolus application, leading to higher handling costs and increased stress and disruption to the flock.
“Ensuring all lambs receive adequate trace element supplementation via an eroding bolus will be a cost-effective way to improve margins,” Liz concluded.