Abortions are usually sporadic, but severe outbreaks occur on occasion. The infection may also result in stillbirths and birth of weak calves. Most fetuses are aborted in the third trimester and are well preserved. The cows are not sick, but retained placentas are common.

What can cause a cow to abort a calf?

Common causes of losses include calving difficulty (dystocia), nutritional deficiencies and infectious diseases. Dystocia can occur if calves are too big or are not situated normally in the birth canal.

What causes miscarriages in cows?

Neosporosis in cattle is caused by a parasite found in the faeces of infected dogs or foxes. Abortion normally occurs between three and eight months of the pregnancy. Infection from dogs can lead to multiple abortions within the herd. Once infected, animals remain infected for life.