This can lead to abortion, calves being born small, weak, deformed or blind, and death of calves within a few days of birth.
Gall hyn arwain at erthyliad, lloi'n cael eu geni'n llai, yn wan, wedi'u hanffurfio neu'n ddall, a marwolaeth lloi o fewn ychydig ddyddiau i'w geni.