Finishing lambs as efficiently as possible is the key to having a profitable system. Ill-thrifty lambs can be a sign of internal parasites and/or trace mineral deficiencies. Commonly, both problems act in tandem and it is important to consider both when finishing lambs.
The main players with minerals when it comes to poor growth rates in lambs are cobalt, copper and selenium. Multiple strategies can be employed on your farm to manage these minerals and ensure deficiency is not a problem for your stores.
Cobalt
Often referred to as “Pine”, cobalt deficiency is usually seen in weaned lambs at pasture during the autumn. Production losses associated with cobalt deficiency may cost in the regions of £10-15 per lamb. (NADIS)
Signs of “Pine” include dullness, poor energy levels, lack of appetite, poor body condition score and poor-quality fleece. These signs can even occur in lambs receiving adequate nutrition. These lambs also respond poorly to vaccination for clostridia and pasteurella and can commonly die of these diseases.
Deficiency occurs when the cobalt concentrations within the soil are low. Deficiency can be confirmed by testing Vitamin B12 concentrations in blood samples from lambs as Cobalt plays a key role in the synthesis of vitamin B12 in the rumen. Alternatively, response to supplementation can be measured to check if deficiency was playing a role in ill thrift.
Oral cobalt sulphate supplementation every month in lambs from around 3 months of age should supply sufficient cobalt for growing lambs. This is a relatively cheap approach to managing potential deficiencies – costing less than 1p per 25kg lamb. Boluses containing cobalt are an alternative option to supplement lambs – a treatment should provide enough supplementation until finishing; however, although labour is reduced; this is more expensive option.
Copper
“Swayback” is a commonly used term in describing copper deficiency within Northern Ireland. This is when lambs are born from ewes who were deficient during mid-pregnancy, and they have hind-leg weakness (swaying at the back end). Growing lambs may also have copper deficiency with signs including poor growth rates, anaemia and poor fleece quality (“steel wool”).
Deficiency occurs when sheep graze ground that is either directly low in copper or high in iron, molybdenum and sulphur. If two or more of these elements exist together in soils, they can act together to bind copper out of the diet. Diagnosis in lambs can be confirmed using blood sampling techniques. Due to the risk of copper toxicity in sheep, it is much more important to prevent deficiency rather than treat it. It has also been found that the symptoms caused by copper deficiency are generally irreversible, even after successful supplementation. Understanding your soils and what minerals are present is an important part in managing copper levels within a flock. Supplementation using copper containing boluses is an option, however care must be taken to ensure excess copper is not supplied leading to toxicity. Always seek tailored veterinary advise before considering copper supplementation within a flock. It is important to note that Texel sheep in particular, are highly susceptible to copper toxicity and care should be taken if supplementation is considered.
Selenium
White muscle disease (WMD) is the most seen problem associated with selenium deficiency in rapidly growing lambs between 2-6 weeks old; (AKA: Stiff lamb disease).
Risk factors associated with selenium deficiency are feeding root crops and home-grown cereals and feeding rations that do not have suitable amounts of minerals included. Soils can be deficient in selenium in certain geographic areas, and it is important to understand if your farm is at risk so that you can take steps to fix this.
Diagnosis of selenium deficiency must be made using an array of information, including the full history, symptoms, breed of sheep and using muscle enzyme testing. Long term selenium level testing can be done using blood samples for GSHPx. Injectable supplementation can be given to young lambs to reduce the risk and clinical signs of selenium deficiency.
Prevention of selenium deficiency is important within flocks particularly of the Texel and Suffolk breeds as they are more likely to become affected by the deficiency. Supplementation can be given in various ways including using boluses, inclusion in the feed using a mineral pack, periodic drenching with mineral drenches or with free access to mineral licks. It is important to note, that similar to copper; selenium toxicity can occur and a supplementation plan should be carefully formulated alongside your vet and nutritionist.
Managing minerals within your flock can lead to a successful finish for lambs. Ensuring you understand the soils you are grazing on and managing these successfully is an important factor of mineral management. Supplementation can then be chosen accordingly to suit the system you have and the deficiencies you know your unit has.
Visit one of our stores and speak with a Registered Animal Medicine Advisor (RAMA) for more information on managing minerals within your flock.
