Selenium boost helps dairy cows.
Newly published research shows that improved selenium status in early lactation dairy cows can help animals as well as profits.
The study, carried out by the Research Institute for Animal Production in Slovakia, shows that an organic selenium supplement increases immunity and reduces milk somatic cell counts that lead to farmgate penalties.
The findings provide fresh encouragement for farmers facing the ever-present challenge of maintaining the highest milk hygiene standards.
Research on a 270-cow commercial dairy herd showed that supplementing cows with an organic selenium supplement led to significantly lower milk somatic cell counts over the first eight weeks of lactation.
In the experiment, a group of 44 cows receiving Sel-Plex organic selenium as part of its mineral ration recorded a 30% reduction in somatic cell count from calving to week eight of lactation - from 249,000 cells/ml down to 174,500 cells/ml.
This compared with a decline of only 7.6% over the same period in 40 cows receiving only inorganic selenium supplementation.
There was also a reduction in clinical mastitis - four in the Sel-Plex group compared with 9 in the control group. Cows were loose housed and milked twice daily, and had an average milk yield of 7,540 litres.
Diets were formulated for 30-litres-a-day milk production.
The results are consistent with the now-established understanding of the key role of selenium alongside vitamin E in stimulating immune function.
Earlier work by William P Weiss, now based at Ohio State University, showed how improving the blood plasma concentration of selenium in a herd has a direct correlation with bulk milk somatic cell count.
That means that improving selenium supply beyond the conventional methods of feeding sodium selenite has become key in the quest for better milk hygiene through reduced mastitis incidence.
Numerous studies have now been carried out to show that organic forms of the element, such as selenium yeast (and specifically Sel-Plex), result in significant increases in whole blood concentrations.
'High somatic cell counts attract penalties from milk buyers, so for many dairy farmers there is an immediate financial incentive to maintain herd levels below a given thresh- old,' said David Wilde of animal-feed experts Alltech.
'In addition, there is a direct correlation between somatic cell counts and milk yield, with lost litres increasing steeply as cell counts rise above the 100,000 cells/ml mark.
'If you consider that a cow with a somatic cell count of 400,000 cells/ml could be under-performing by as much as 600 litres a year - and may also be contributing towards a herd cell count that is attracting a penalty - the investment in the right selenium source could be very sound practice indeed.'