Slurry gas warning after unusual cattle deaths
While the danger posed by stored slurry has been well-documented, and is well-understood by farmers, the unusual events that led to the fatalities are worth highlighting.
During a recent dry spell, a beef producer in the Scottish Borders took advantage of the conditions to begin emptying some of the slurry stored under the slatted floors of his beef sheds.
Having taken out two or three loads, he returned to find four large steers dead. They had been suffocated by hydrogen sulphide gas.
It is well-known that mixing and handling slurry can produce this toxic gas, which is invisible, although it smells like rotten eggs.
In a confined area, it rapidly kills both cattle and humans by suffocation.
It is also understood that adding silage effluent to slurry increases the risk, because the nutrients in the effluent feed the bacteria in the slurry, which are responsible for producing the hydrogen sulphide gas. What was unique in this recent case was that the farm had just started using waste plaster board, containing high levels of gypsum, to help dry up the straw bedding being used in other buildings.
However, heavy rain had washed some of that gypsum into the slatted shed and down into the slurry store.
Gypsum, or calcium sulphate, contains high levels of sulphur, which encourages the bugs to produce even greater amounts of hydrogen sulphide from the slurry.
SAC has warned farmers who are using waste plaster board, or other gypsum sources to remember this message, and, as an additional safeguard, ensure that the product is stored and used in a way which avoids any potential contamination of slurry supplies.
SAC also reminds farmers that when emptying slurry stores, there are several key safety points:
* Before starting, take all animals out of the building and open all ventilation, doors, etc.
* Never enter the building when the pump mixing the slurry or emptying the store is working.
* Ensure there is always another person present who stays outside the shed and can summon help, if needed, but without entering the building and endangering themselves.
* If entry is necessary, only appropriately supervised, competent persons, equipped with harness, lifeline and breathing apparatus, should enter slurry storage cellars.
