Pigs on alert
In a RASFF alert on Tuesday, the UK notified the authorities that the level of selenium in a mineral premixture for pigs produced there and distributed to other EU countries was too high. The premix product has been withdrawn from the market.
Selenium is an essential but potentially toxic trace mineral for swine. The total maximum levels of dietary selenium allowed in the EU are 0.5 mg/kg.
According to the literature, acute selenium toxicosis is generally not a problem under most post pig feeding programs, but may occur when feed is poorly mixed, premixes are weighed inaccurately, or premix amounts are miscalculated, resulting in higher than-normal selenium concentrations in the diet.
The effects of ingesting a large quantity of selenium, greater than 20 ppm, include feed refusal, weight loss, respiratory distress, spinal paralysis, incoordination, hair loss, and death.
“Selenium is one of those trace elements whose typical inclusion rate in pig diets is very low, <0.5ppm, and the margin for error up to a toxic level is relatively limited,” Kevin Stickney, pig product manager at UK feed producer, Harbro, told us.
“Most trace elements would fit under a banner of an inverted ‘U’ shape in terms of sharply increasing effectiveness, a short plateau of little or no improvement in effect followed by a precipitate plunge through decreasing performance,” he added.