WA Livestock Disease Outlook - for producers

Abortions in mixed-age dairy cows

  • Abortion in mixed-aged dairy cows that appeared clinically normal was investigated in the South West.
  • Over one week six cows aborted. All were in the second trimester of pregnancy.
  • Blood samples were collected from the affected and other non-affected cows in the herd. Tissue samples were collected from the aborted calves and all were submitted for laboratory examination.
  • Testing carried out for the reportable disease Brucella abortus as a cause of abortion was negative.
  • Microscopic examination and testing confirmed Neospora caninum as the cause of the abortions.
  • Of the 32 blood samples, 16 were positive for N. caninum, indicating widespread exposure within the herd.
  • Dogs are the definitive hosts for the protozoan Neospora and they shed the infective stages. Foxes have never been implicated in the spread of this disease.