Introduction

• This article is an overview of the causes of abortion in cattle.  
  • It is not exhaustive.
  • Further details on the conditions, microorganisms and investigative procedures mentioned, can be found by following the links within the article.
• Abortion is defined as fetal death and expulsion between 42 and 270 days of gestation.
  • Calves born dead after this time would be defined as stillbirth and before 42 days it would be defined as embryonic loss.
• The greatest risk of fetal loss is during the first trimester of gestation, this risk then progressively decreases as gestation advances, with a slight increase in the risk toward the last month of gestation.
• Many abortions go unnoticed or undiagnosed.
  • Non-pregnant cows are often investigated for suspected fertility problems, when in fact they have suffered embryo/fetal loss.
• Determining the cause of an abortion is not simple and attempts to arrive at a diagnosis are frequently frustrating and unproductive Investigating abortion outbreaks.
• Diagnostic efforts should be initiated at the clients request or advised when the vet has concerns.
  • Concerns should be raised if the annual incidence of abortion within the herd is 5% or more.
  • Regional variations will determine cut offs. For example, some farms in California accept Neospora related abortion rates of up to 10%. This is because they are unable to control infection from wild coyotes Neosporosis.
• Keep in mind that in herds with early pregnancy diagnosis, the proportion of acceptable abortions can be higher, compared to (beef) herds where pregnancy testing is more likely done later on in gestation, after which cows may have lost their pregnancy and have conceived again.
• The economic losses vary greatly per farm.
• Good record keeping is essential to monitor trends.
  • Records may also assist with diagnosis and treatment plans.

Diagnostic investigation

Non-infectious causes of abortion

Infectious causes of abortion

Prevention

Further Reading

Publications

Refereed Papers

• Recent references from PubMed and VetMedResource.
• López-Gatius F & Hunter R (2017) From pre-ovulatory follicle palpation to the challenge of twin pregnancies: Clinical reflections following one million gynaecological examinations in dairy cows. Repro Domes Anim 52, 4–11 PubMed.
• Borel N, Frey C F, Gottstein B, Hilbe M, Pospischil A, Franzoso F D & Waldvogel A (2014) Laboratory diagnosis of ruminant abortion in Europe. Vet J 200 (2), 218-229 PubMed.
• Sobrova P, Vojtech A, Vasatkova A, Beklova M, Zeman L & Kizek1 R (2010) Deoxynivalenol and its toxicity. Interdiscip Toxicol 3 (3), 94–99 PubMed.
• DeHoogh W (1989) Dicumarol toxicity in a herd of Ayrshire cattle fed moldy sweet clover. Bovine Practitioner 24, 173.
• Coulson J C, Butter J & Thomas C (1983) The herring gull Larus argentatus as a likely transmitting agent of Salmonella montevideo to sheep and cattle. Epidemiology & Infect 91 (3), 437-443 PubMed.
• Hall A & Jones P (1977) A study of the pathogenesis of experimental Salmonella dublin abortion in cattle. J Comp Pathol 87 (1), 53-65 PubMed.

Other sources of information

• MSD, Plummer P [online]. Overview of Coxiellosis. Website: www.msdvetmanual.com. Last accessed 14th March 2018.
• Bovilis [online]. Salmonella. Website: www.bovilis.ie. Last accessed 14th March 2018.
• European food Safety Authority. Zoonoses monitoring. United Kingdom. TRENDS AND SOURCES OF ZOONOSES AND ZOONOTIC AGENTS IN FOODSTUFFS, ANIMALS AND
  FEEDINGSTUFFS. Including information on foodborne outbreaks, antimicrobial resistance in zoonotic and indicator bacteria and some pathogenic microbiological agents. (2015)
  PDF: www.efsa.europa.eu (last accessed April 2018).