e.g. Selenium requirement for 180 cows would fit into a take-away fries salt sachet, but given as bagged mineral has to be dispersed accurately in a 5-tonne TMR mix.
Essential trace elements are needed in such tiny quantities that small day-to-day inconsistencies can affect cattle performance, according to vet Dr Elizabeth Berry from Animax. “With selenium, for example, the daily amount for 180 dairy cows is similar to one salt sachet that you get with a portion of take-away fries and the same applies to other cattle types.
“No matter how thorough the mixing appears to be, there is always a risk of unpredictable particle dispersal in TMRs that would jeopardise accurate supplementation and animal performance.”
Among other supplementation routes, Dr Berry suggests that free-access licks are equally subject to animal-to-animal variation due to preferential uptake and herd pecking order, while drenches need repeating frequently.
She adds that financial viability depends on farmers managing what they can control with great precision to optimise productivity relative to production costs.
With autumn transition from grazing to housed feeding in mind, Dr Berry explains that much of UK grassland, and therefore silage and hay, is deficient in essential trace elements. “Without supplementation, functions affected by deficiencies include immunity, energy metabolism, digestive enzymes and breeding hormones,” she says.
“Sub-optimal function in any one of these is likely to have adverse effects on cattle productivity, whether dairy or beef, and financial performance. Reliable trace element supplementation to help calves and yearlings make maximum use of forage is also good business and affordable.
“Among available methods, one offering accurate daily supply, supplementing for six months and single handling is a Tracesure cattle leaching bolus to supply cobalt, iodine and selenium, with or without copper. Even if silage or hay is plentiful enough to cover the need for bulk feed, most will be deficient in some trace elements, affecting all ruminants’ abilities to utilise forage nutrients fully.”