By Donald Stotts  STILLWATER, Okla. – Cattle producers need to follow recommended livestock-care checklists to mitigate significant dangers that arctic blasts bring to animal health and production, said Oklahoma State University experts.  Ranchers might not typically think about frozen water sources during a mild winter, for example.  So it’s important to remember that cattle in southern Great Plains states are relatively naïve when it comes to the presence of ice in the field,…