UK Soils in common with most agricultural land across the EU are deficient in selenium, a vital mineral for a healthy immune system.
Trials conducted across the UK in 2014 have shown that the guideline selenium content is consistently not met in the production of grass and forage, in fact many control groups contained less than half the recommended level of 0.1ppm of selenium (Se).
The trials conducted by fertilizer company, Yara UK, across the UK and IRE looked into the application of Se through fertilizer. The results have shown that where fertilizer with added Se was applied, it consistently increased Se availability in the grass to above the guideline level.
It is well-known amongst dairy farmers that cows with Se deficiencies are likely to present with higher mastitis outbreaks and lower fertility. Less commonly known is that it can also cause:
White muscle disease
Higher cell counts
Unthriftiness, growth depression and diarrhoea
Retained placenta, cystic ovarian disease and anaemia
“Based on the Se deficiencies seen across all the trials we have conducted this year, it is essential to consider the level of all nutrients readily available in forage, in particular Se, as most herds will not be gaining the Se concentrations required from forage alone,” explains Jez Wardman, Agronomist at Yara UK.
At the Grasstech event near Elgin, Scotland 8 trial plots were plots were set up on various seed mixes including;
|Plot 1||2 year silage mix|
|Plot 2||3 year silage mix|
|Plot 3||5 year silage mix|
|Plot 4||Multipurpose mix|
|Plot 5||Multipurpose mix|
|Plot 6||Long Term Grazing Mix|
|Plot 7||Long Term Grazing Mix|
|Plot 8||Red Clover Mix|
All plots showed a significant increase in Se availability after fertilisation with added Se, with the long term grazing mixes and red clover showing the greatest benefit climbing from 0.06ppm and 0.14ppm respectively to 1.16ppm and 1.17ppm.
Graph – Selenium levels in samples collected during Grass Tech demonstration
*YaraBela Nutri-Booster 25-0-0 is a straight nitrogen product also containing Sulphur and Sodium Selenate.
**YaraMila Top Stock 25-5-5 is a compound NPK product also containing Sodium Selenate.
“There are various ways in which you can add Se to the diet,” explains Mr Wardman. “Either byincreasing the concentration in food through feed supplementation, increasing the concentration in forage through fertilizer supplementation or a combination of both.”
Mr Wardman advises that some farms will need to reconsider the way they approach adding Se into the diet. “Some options from inorganic sources do not allow efficient transfer of Se and thus the Se content in the blood remains below critical levels.”
“Grass takes up Se during its normal growth pattern and incorporates it into its proteins. This is an important aspect as in this form the Se is more available than when in the inorganic salt forms associated with mineral licks and supplements.”
In addition to the trials, samples were collected from ten leading farms involved in the Yara Grass Prix competition; a competition run throughout 2014 to reach the highest energy yield (ME per hectare) across two cuts of silage. All farms outperformed the national average for fresh weight, ME and DM value however analysis of the samples highlighted that among these leading farmers the average Se level across first and second cut silages was only 0.04ppm significantly below recommended levels.
Graph – Selenium levels in all samples collected during Yara Grass Prix competition.
“Analysis of soil is recommended as deficiencies can vary on a field by field basis, this will allow decisions to be made based on all macro and micro nutrient availability that can impact upon animal health and production,” concludes Mr Wardman.