Abortions are not an uncommon occurrence to see in spring-calving herds, but all cases should be investigated to determine the cause.
There are a number of reasons as to why a cow or heifer will ‘throw a calf’.
Any illness where a cow has a very high temperature can result in abortion – but it could also be caused by a simple slip or fall in the yard, or shed to pathogens infecting the pregnant cow or heifer.
Aborting cows do not normally display signs of illness, unless there is retention of the foetal membranes (afterbirth).
Individual or abrupt abortions, may be caused by an infectious disease or a simple injury during pregnancy.
Any infectious pathogens that come into contact with the placenta in the pregnant cow/heifer and that cause damage to the foetus and/or the placenta can result in abortions.
When infection occurs in early pregnancy, the resulting embryo loss may only be apparent when cows are found to be ’empty’.
Several abortions occurring within a relatively short period of time may indicate that multiple cows in the herd have been exposed to an abortion-causing infectious disease.
An abortion may indicate serious health issues in the wider herd, and could lead to significant financial losses.
However, not all abortions are caused by infections, but it is wise to assume that the cause is infectious when dealing with an animal that has aborted.
Abortions
When dealing with a cow that has aborted, it is firstly important to ensure that you don’t handle any of the material without protective clothing – such as gloves.
It is also important that you do not allow animals, especially dogs or foxes to have access to the material.
Identify the aborted cow – if not visually obvious, ask your vet to examine the group of cows to identify the one that has aborted and to take samples for testing from her.
Remove the aborted material (foetus and cleaning) and place in a strong plastic bag, you should then speak to your vet and then bring it to the laboratory for testing.
Clean and disinfect the area where the abortion occurred.
Closely monitor other pregnant cows – inspect pregnant cow groups at least once a day, and isolate any cows showing signs of imminent abortion.
Isolate the aborting cow or heifer immediately, especially from other pregnant cattle, for at least three weeks or until laboratory results are received.
Isolation is important as abortions within herds can be caused by: brucellosis, leptospirosis, salmonellosis, neosporosis, mycotic abortion, bovine viral diarrhoea (BVD) and infectious bovine rhinotracheitis (IBR).
A cow that aborts at this time of the year is likely not going to be retained within the herd, but you should speak with your vet on how to address the issues in your health plan in light of results.