Sheep producers are being urged to step up forage testing ahead of tupping after research linked hidden cobalt deficiencies in ewes with poorer lamb vigour.
The complex and variable nature of cobalt levels in grassland soils makes its status hard to track, says Alison Bond, of nutrient specialists Rumenco. But routine analysis can help identify deficiencies before they affect flock performance.
“Cobalt is particularly important as it is required in the synthesis of vitamin B12 by rumen microorganisms. Where vitamin B12 is deficient, sheep can suffer poor growth rates, weight loss and anaemia,” says Dr Bond.
Cobalt can be difficult to manage because levels vary significantly between sites and over time. Soil acidity, organic matter, cropping and rainfall can all influence its availability. Sub-clinical deficiency presents a particular challenge because affected sheep may show no obvious symptoms.
Independent research by SAC found lambs born to ewes with sub-clinical cobalt deficiency were less active during their first three days. They also explored less and nosed their mothers less frequently.
“Those behaviours are important because they indicate whether newborn lambs are successfully seeking the teat and consuming colostrum,” says Dr Bond. “This work shows very clearly that lambs born from ewes with sub-clinical cobalt deficiency, which is typically without symptoms and goes unnoticed, had lower levels of activity, less exploration, and fewer instances of nosing.”
Dr Bond recommends soil and forage testing to establish cobalt and other mineral levels. Where availability is uncertain, supplementation should start before tupping and continue afterwards. Feed blocks or mineral buckets can provide a practical option where deficiencies are identified. Products can be selected according to whether sheep require minerals alone or additional energy and protein.
Rumenco recommends its Supalyx 4-in-1 mineral, vitamin and trace element bucket where no extra energy is needed. Its Rumevite Sheep Super feed block provides energy and protein alongside minerals and vitamins.