Livestock producers face significant productivity losses from selenium deficiency in sheep and cattle, according to Elanco Senior Brand Manager for Cattle Kim Krilich, who warns that hidden performance drops often occur before clinical symptoms appear. Essential for metabolic functions, disease resistance, muscle function, and fertility, selenium shortfalls can affect all classes of livestock grazing on deficient soil types across Australia.
Soil Deficiencies and High-Rainfall Vulnerability in Australian Pastures
Deficiencies occur when livestock consume insufficient selenium from pasture or rations, or ingest the mineral in a form they cannot absorb and metabolise, according to Ms Krilich. Many soil types across Australia—including sandy coastal, acidic, and granite soils—lack adequate selenium levels, as documented by researchers G.J. Judson and D.J. Reuter in the 1999 publication Soil Analysis: An Interpretation Manual.
The problem is particularly prevalent in high-rainfall areas receiving more than 450 millimetres of rain per year. In these regions, improved, irrigated, or fertilised pastures grow rapidly during events like a spring flush, diluting the mineral concentration available to grazing animals. According to veterinary literature compiled by R. Puls in Mineral levels in animal nutrition – Diagnostic Data, young livestock experiencing clinical deficiency may display scouring, a stiff gait, an arched back, lameness, reduced growth rates, increased susceptibility to parasites and disease, and sudden death from heart failure.
Recognizing Sub-Clinical Losses and Adult Symptoms
Adult sheep and cattle suffering from low selenium show distinct signs, including ill-thrift, reduced fertility, stillbirths, weak lambing and calving, retained foetal membranes, mastitis, and lower wool and milk production, as outlined by Puls. However, Ms Krilich emphasises that these visible indicators represent only the tip of the iceberg.
Did you know? Productivity and performance losses in livestock often occur well before any physical symptoms of selenium deficiency become noticeable on-farm.
Producers cannot rely solely on visual inspection to gauge mineral status. Ms Krilich recommends consulting a veterinarian or animal health advisor before starting any supplementation program. Determining exact status is best achieved using blood or liver samples taken from livestock that have not had access to supplementary selenium sources.
Long-Acting Therapy and Administration Protocols
Sheep and cattle with low selenium levels or those at risk of clinical deficiency require treatment with a suitable long-acting therapy, such as Selovin LA from Elanco. A single treatment elevates blood selenium levels for up to 18 months in sheep and up to 12 months in cattle, providing a steady supply while minimising the risk of toxicity.
Administration requires a subcutaneous injection using an Elanco 7 mL or 15 mL injector fitted with an 18-gauge needle for sheep or a 16-gauge needle for cattle, with needles measuring less than 15 mm in length. According to product directions:
- Lambs: 0.5 mL per head
- Sheep: 1 mL per head
- Cattle: 1 mL per 50 kg body weight
Pro Tip: Always weigh livestock to calculate the correct dose rate based on the heaviest animal in the mob, taking care to avoid overdosing during early pregnancy.
Proper technique and hygiene are critical during administration. Ms Krilich advises placing the injection site high on the neck behind the ear to minimize carcase damage. Operators should raise the skin into a tent and insert the needle parallel to the body to release the dose under the skin, taking care to avoid self-injection. Needles must be clean and sharp and replaced as necessary, while administration during wet or dusty conditions should be avoided.
Managing Critical Production Stages with Short-Acting Options
Beyond long-acting therapies, livestock can experience sub-clinical mineral deficiencies when feed intake fails to meet nutritional requirements during critical production stages. These stages include periods before joining, lambing, calving, or weaning. In these situations, animals may benefit from short-acting selenium supplements such as Cobalife VB12 Plus Selenium or MultiBoost with B12 for cattle, according to Elanco.
Producers seeking further information on mineral supplementation solutions can contact a local Elanco representative or the Elanco Customer Service team on 1800 995 709. Elanco advises that results may vary based on current mineral status and additional trace mineral sources, and operators should always read and follow label directions.
Frequently Asked Questions
What are the primary signs of selenium deficiency in young livestock?
Young animals may experience scouring, a stiff gait, lameness, arched backs, reduced growth rates, higher susceptibility to disease, and sudden death from heart failure, according to veterinary data cited by Elanco.
How long do long-acting selenium treatments elevate blood levels?
A single treatment of a long-acting therapy like Selovin LA elevates blood selenium levels for up to 18 months in sheep and up to 12 months in cattle.
What is the correct injection site for Selovin LA administration?
The injection should be administered subcutaneously high on the neck behind the ear to minimize carcase damage, using a tented skin fold and a needle inserted parallel to the body.
How should a producer determine the selenium status of a herd or flock?
Status is best determined through blood or liver samples collected from animals that have not had access to supplementary selenium sources, following consultation with a veterinarian or animal health advisor.
What is your current strategy for managing trace mineral deficiencies in your mob? Share your experiences or questions in the comments below.
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