Noninfectious causes of abortion in goats include plant toxins, such as broomweed or locoweed poisoning; dietary deficiencies of copper Copper Deficiency in Goats Copper deficiency may cause locomotor difficulties in goats in two distinct ways. Abnormal bone growth with increased bone fragility can predispose to fractures of long bones. Independently... read more , selenium, vitamin A, or magnesium; and certain drugs such as estrogen, glucocorticoids, phenothiazine, carbon tetrachloride, or levamisole (in late gestation).
Major infectious causes of abortion in goats are chlamydiosis Overview of Chlamydiosis Bacteria of the order Chlamydiales are ubiquitous, obligate intracellular gram-negative bacteria. Within the host cell, they replicate via a unique developmental cycle competing with the host... read more , toxoplasmosis Toxoplasmosis in Animals Toxoplasmosis is an important zoonotic protozoal infection worldwide. All homoeothermic animal species may be infected. Infection is generally asymptomatic and chronic in immunocompetent individuals... read more , leptospirosis Leptospirosis in Animals - Overview Leptospirosis is a zoonotic disease with a worldwide distribution caused by infection with any of several pathogenic serovars of Leptospira. The disease affects virtually all mammals... read more , brucellosis Brucellosis in Goats The signs of brucellosis in goats are similar to those in cattle. The disease is prevalent in most countries where goats are a significant part of the animal industry, and milk is a common source... read more , Coxiella burnetii, and listeriosis Listeriosis in Animals The most common clinical manifestation of listeriosis is a localized ascending asymmetric infection of the brain stem of ruminants by Listeria monocytogenes. The resultant meningoencephalitis... read more . Campylobacter causes abortions but is not nearly as important in does as in ewes.
Brucellosis as a Cause of Abortion in Goats
Brucella melitensis Brucellosis in Goats The signs of brucellosis in goats are similar to those in cattle. The disease is prevalent in most countries where goats are a significant part of the animal industry, and milk is a common source... read more is the principal organism involved in abortions in animals with brucellosis; B abortus is occasionally involved. Abortion may be accompanied by mastitis and lameness and is most common in the fourth month. The placenta is grossly normal, but does may develop chronic uterine lesions. Infection in adults is lifelong, with organisms shed in the milk (B melitensis is zoonotic but rare in the USA). In the USA, control is by test and slaughter. Tube agglutination and card tests can be used as screening tests.
Caprine Herpesvirus 1 as a Cause of Abortion
Caprine herpesvirus 1 is closely related to infectious bovine rhinotracheitis virus of cattle and causes sporadic outbreaks of late-term abortions often unassociated with other clinical signs. The virus also causes vulvovaginitis, balanoposthitis, and respiratory disease in adult goats and enteric and systemic diseases in neonatal goats. Fetuses can be fresh or autolyzed and do not contain diagnostic gross lesions. Presumptive diagnosis is by microscopic identification of necrosis with the presence of intranuclear inclusion bodies in the liver, lungs, and other organs. Definitive diagnosis is by identification of caprine herpesvirus 1 by isolation, PCR, or immunologic staining methods. Not all fetuses contain lesions or virus, so multiple fetuses should be submitted. Infected goats can become latently infected and can shed the virus during times of stress. Vaccines are not commercially available in the USA.
Chlamydiosis (Enzootic Abortion) in Goats
Chlamydophila abortus (the agent of enzootic abortion of ewes) is the most common cause of abortion in goats in the USA. In naive herds, up to 60% of pregnant does can abort or give birth to stillborn or weak kids. Abortions can occur at any stage of pregnancy, but most are in the last month. Reproductive failure is usually the only sign of C abortus infection, but occasionally there is concurrent respiratory disease, polyarthritis, conjunctivitis, and retained placentas in the flock. Aborted kids are usually fresh with no gross pathology. Placentitis is usually present and consists of reddish brown exudate covering cotyledons and intercotyledonary areas. Microscopically, necrotizing vasculitis and neutrophilic inflammation are present in the placenta. Chlamydial organisms can be visualized in appropriately stained placental smears, but they cannot be differentiated from Coxiella burnetii. Fluorescent antibody or immunohistochemical staining, ELISA, PCR, or culture can be used to definitively identify C abortus. The placenta is the specimen of choice, but sometimes the diagnosis can be made by testing liver, lung, and spleen.
During an outbreak, aborting does should be isolated, and tetracyclines given orally or parentally. There is no chlamydial vaccine for goats, but the vaccine for sheep is relatively effective. Like sheep, goats that abort are immune. Sheep that abort due to C abortus remain infected for years, if not life, and shed the organism during ovulation; whether this occurs in goats is not known. C abortus is zoonotic, occasionally causing serious disease in pregnant women.
Coxiella burnetii Infection as a Cause of Abortion in Goats
Coxiella burnetii Coxiellosis is increasingly recognized as an important cause of caprine abortion. Occasional outbreaks also occur in sheep. Late-term abortions, stillbirths, and weak lambs are the common presentations. Up to 50% of the flock may be involved. The placenta is covered by gray-brown exudate and the intercotyledonary areas are thickened. Microscopically, there is a necrotizing vasculitis in the placenta, and many chorionic epithelial cells are distended by small, coccobacillary organisms <1 mcm in diameter. Infection involves only the placenta; without it, the diagnosis usually cannot be made. Diagnosis is by identification of C burnetii by immunologic staining methods, PCR, or by isolation. Coxiella is zoonotic, causing Q fever in people.
Leptospirosis as a Cause of Abortion in Goats
The most common serovars of Leptospira Leptospirosis in Ruminants Several pathogenic strains of Leptospira bacteria infect ruminants. Some are specifically adapted to cattle, whereas others are incidental but can still cause disease. Clinical signs... read more involved in caprine abortion are Grippotyphosa,Pomona, Icterohaemorrhagiae, and Autumnalis. Although sheep are relatively resistant to leptospirosis, goats are susceptible, with abortions occurring at the time of leptospiremia. Some does have anemia, icterus, and hemoglobinemia; others are afebrile and are not icteric. Diagnosis is by serology or identification of Leptospira spp in the dam’s urine, the placenta, or fetal kidney.
Listeriosis as a Cause of Abortion in Goats
Listeria monocytogenes Listeriosis is a common pathogen in goats and causes sporadic abortions. There are no specific fetal lesions, and the fetus is often autolyzed. Does usually show no signs before abortion but may develop severe metritis after abortion. Diagnosis is by isolation from the placenta, abomasal contents, or uterine discharge. In the rare case of a herd outbreak, preventive treatment with tetracycline is recommended.
Toxoplasmosis as a Cause of Abortion in Goats
Toxoplasmosis Toxoplasmosis is a common cause of abortion in goats in the USA, and toxoplasmal abortion in goats is similar to the syndrome in ewes Toxoplasmosis Also see Management of Reproduction: Sheep. Abortion in ewes, as in cows, is not always easily diagnosed. Although many of the toxins that cause abortion in cows also cause problems in ewes... read more .