SORGHUM POISONING IN BUFFALOES

摘要

Sorghum crops are having various amounts of dhurrin, a cyanogenic glycoside that releases hydrogen cyanide (HCN) after hydrolysis (FAO, 2010). The amount of dhurrin depends on plant age (higher when young), growing conditions such as fertilization (high N amounts or unbalanced NPK fertilization increase dhurrin content), frost exposition and water stress (Rhykerd and Johnson, 2009). When the plant is damaged by frost, mastication or water stress, plant enzymes convert the glycoside to other chemicals, including hydrogen cyanide (HCN). On grazing sorghum, cyanide poisoning is the more likely risk, but nitrate-nitrite poisoning is also a possibility. Hay made from sorghums containing toxic amounts of cyanide, nitrate or both will remain dangerously toxic. Ensiling significantly reduce or eliminate these risks. High stocking rates (such as 10-15 head/ha for cattle) and rotational grazing is another way to prevent HCN poisoning as these methods limit intake (Heuze et al, 2012).