Tackling selenium deficiency on farm

Peter Orr from Rathfriland, Co. Down has experienced first-hand the devastating effects that selenium deficiency can have on a herd. Unusually, this deficiency only affected his first time calvers where the least affected had symptoms characterised by a sharp fall in both intakes and milk yield after calving. 

The problem had been on-going for a number of years with uncharacteristic selenium deficiency symptoms in freshly calved heifers. Up to this point Peter had relied on his dry cow cake to supply his heifers’ selenium requirements in the last weeks of pregnancy. It wasn’t until he blood sampled a batch of these heifers that he discovered it was a selenium deficiency with low vitamin E levels also being implicated. 

Peter came up with a two pronged approach to prevent this selenium and vitamin E deficiency reoccurring. All heifers are now injected a month before calving with a vitamin E and selenium product and Peter also began fortifying grass by applying YaraBela Nutri Booster (25% N + 5% SO3) which contains selenium selenate. The sulphur in this product is ideal for maximising nitrogen use efficiency which improves yields but also protein and sugar levels in grass. 

This is Peter’s second year using Nutri Booster to lift his grass selenium levels to the desired 0.3 ppm. This is adequate to supply a dairy cow’s daily selenium requirement, with organically bound selenium being utilised more efficiently than other oral forms of selenium supplementation. Silage and grazing ground receives Nutri-Booster which is effective in maintaining enough dietary selenium in forage all year round.

Benefits of applying selenium with fertiliser 

The benefit of applying selenium with fertiliser is that the grass takes up selenium during its normal growth pattern and incorporates it into its proteins. This is an important aspect, as in this form the selenium is more available than when in the inorganic salt forms. These inorganic salts are associated with mineral licks and supplements which are often rapidly excreted. A second benefit is that all the animals take in selenium in proportion to their grass intake whether grazed or conserved, rather than relying on equal access to supplements. 

More information on the Booster range of selenium enriched fertilisers