Abortion issues

Loss of pregnancy in the period from day 43-260 in a pregnancy is defined as an abortion. Loss of pregnancy earlier is defined as early embryo loss, while birth of a live and stillborn calf after pregnancy day 260 and until due day (280 days) is defined as early birth.

Finding the problem
When an abortion outbreak is defined, it is based on the number of abortions being in the range 2.1 to 5.4% - corresponding to one in 50 to one in 18 cows in the herd having an abortion.

Causes
There are many different reasons why a cow or heifer has an abortion. Some of the abortions will be due to chromosome disorders, deformities, hereditary diseases or disease in the pregnant animal, which is why abortions do sporadically occur in all herds. A more excessive cause of abortions is microorganisms infecting the foetus and/or foetal membranes. In addition, certain chemical connections (nitrate-nitrite, herbicides) may cause abortion. In general, identification of abortion causes is low. In routine examinations of abortion tissue, the cause was only found in 40-45% of cases; of those 90% were caused by infections.

Action plan and focus areas

• Go through the herd and determine the sequence of events
• Clinical examination of the animals having an abortion
• Laboratory tests (foetus, placenta, blood samples from individual animals or groups of animals in the herd, feed etc.)
• Decision on likely causes
• Initiate preventive measures.
  
  Focus on:
• Finding the most likely cause
• Adding enough nutrient substance
• Minimising stress
• Avoiding contamination

Source: SEGES, Denmark