NEW ZEALAND – Cows receiving swedes as part of a winter foraging diet should be monitored closely for signs of weight loss, grazing habits and photosensitivity.
This is according to levy board DairyNZ, which has urged farmers to be “extra vigilant” and advised that all young stock should be checked.
Scientists launched an investigation last year when mystery cow deaths were reported in cows eating swedes. read more
Risk increases as the swede gets older and the percentage of the diet becomes more swede and leaf, added DairyNZ.
Regrowth as temperatures lift are a key period of risk as swedes enter reproductive stages.
For this reason, DairyNZ has suggested cows are moved onto a single crop for the whole winter.
Elevated glucosinolate levels are believed to be responsible for the deaths due to complications in the liver, particularly when late pregnancy and early lactation cattle graze mature swedes.
Dairy NZ said: “The higher the proportion of dry matter that swede contributes to the cow's total diet the higher the likely incidence of ill-health effects in cows.
“Farmers should watch for animals with sudden weight loss, photosensitivity or if one or two cows die, they should seek veterinary advice immediately.” read more
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