7 Causes Of Abortion In Small Ruminants That Are Contagious To The Herd
The diagnosis of abortion in small ruminants was and remains a difficult challenge for veterinary professionals. A good medical history, a fetal necropsy, and a placental examination – in addition to laboratory tests – remain the most useful tools for this.
To prevent infectious agents from spreading throughout the herd, it is important that breeders know the possible causes so that they know how to proceed. Next, we will describe seven of the most common abortifacient pathologies in small ruminants.
Abortion in small ruminants: bacterial causes
Next, we’ll talk about the main bacteria that cause miscarriages in herds.
Brucellosis
This is the general name given to infections caused by bacteria of the genus Brucella. Cattle, for example, are usually affected by Brucella abortus and rarely by Brucella melitensis . With small ruminants, exactly the opposite occurs, as the outbreaks of abortions by B. melitensis are quite abundant.
In addition to representing a risk to herds, this disease is also a public health problem, as B. melitensis is a zoonosis. This means that this disease is transmissible from animals to humans.
Clinically, the disease is characterized by the presence of miscarriages and other reproductive problems, such as retained placenta. It is essential to note that the bacteria can also infect males, causing inflammation of the genitals.
Available information shows that the biggest problem at the time of contagion is the abortifacient remains. Therefore, it is important to sound the alarm when there is an outbreak of abortions in the herd at the end of pregnancy.
enzootic abortion
The causative agent is Chlamydophila abortus, an intracellular microorganism that causes miscarriages and the birth of very debilitated offspring. This disease is highly contagious and can infect the entire herd in a matter of days. Furthermore, like brucellosis, it is also a zoonosis and can cause miscarriages in women.
Among goats, abortion can occur at any time during pregnancy , while in sheep it is more common in the second half, after two weeks.
Unfortunately, there are few signs that allow predicting the miscarriage of the female. At most, changes in the mother’s behavior are observed and abnormal vulvar secretions can be found in the last 48 hours of pregnancy.
Q fever
This disease caused by Coxiella burnetti affects almost all domestic mammals, a group that includes small ruminants. It is very contagious, but usually does not cause symptoms in animals. In addition, just like the above, it can also be a zoonosis.
Digestive bacteria that cause miscarriages in small ruminants
Bacteria of the genus Campylobacter spp. can cause abortions if the right conditions are present. In addition to small ruminants, they can also infect cattle, but this occurs in a different way.
Reproductive disease in goats and sheep occurs after an intestinal infection that triggers bacteremia – the passage of bacteria into the blood. This is how microorganisms reach the uterus.
listeriosis
The Listeria monocytogenes is a positive GRAM bacteria that can cause abortions usually late in pregnancy. One of the most telling signs for suspecting its presence as a causative agent is seen during the examination of fetuses.
These fetuses usually have necrotic foci one or two millimeters in diameter in the liver and lung, although they do not always appear.
Abortion in small ruminants: parasitic causes
Next, we’ll talk about the main parasites that cause abortions in herds.
toxoplasmosis
The Toxoplasma gondii is a protozoan parasite which vascular endothelial cells and is a common cause of embryonic death and abortion in sheep and goats. These miscarriages can occur throughout pregnancy, but are more frequent towards the end.
They occur in females of any age, although they are more common in first-time mothers. These parasitic abortions occur mainly if the infection is acquired during the pregnancy itself.
neosporosis
It is true that neosporosis is a disease of great importance in cattle and that classically it has been considered of little relevance for sheep, but in recent years, the protozoan Neospora caninum has been associated with the appearance of abortive outbreaks in this domestic animal.
Infected animals can abort or transmit the parasite to the fetus. Furthermore, these congenitally infected ewes can, in turn, transmit the disease to their offspring.
Abortion in small ruminants: the importance of controlling the transmission of these abortive agents
When fighting diseases that affect livestock, we cannot only concern ourselves with those that cause adult mortality, as animal husbandry is based on reproductive success and it is important that each pregnancy comes to term and that the birth of offspring occurs properly .
Therefore, the person responsible for a creation must be careful to avoid the contagion of these pathologies so that abortive outbreaks do not occur, even more taking into account the possibility that the causative agents also cause diseases in humans.
