Cattle herds from North Dakota to southern Texas are shrinking, as farmers unable to feed their animals are taking them to auction, in some cases selling off breeding stock that took decades to accumulate.. Grazing has become impossible in many areas, and to make things worse, if it rains, grazing may poison cattle, according to scientists at Kansas State University.
Plants that are struggling in a drought period develop nitrate deposits after a rainfall that can be six times the lethal level, said Sandy Johnson, livestock production specialist at K-State Research and Extension.
She suggested that, since concentrations are highest at the base of plants, farmers set the cutter bar at harvest at 6 to 10 inches above the ground, and make sure that cattle are not allowed to graze on the stubble. Ensiling the plant matter will reduce nitrate concentration by up to 60 percent, but that still may be a lethal dose, she said.
She added that not only crops such as corn are dangerous; in drought conditions, weeds such as kochia and pigweed accumulate nitrates.
Johnson recommended waiting seven to 10 days after a rainfall before harvest, to allow the nitrate levels to decrease naturally, and possibly inoculating cattle with bacteria capable of reducing the toxic effect of nitrates.
by Pete Hisey on Wednesday, August 16, 2006