Equine Abortion and Stillbirth in Central Kentucky during 1988 and 1989 Foaling Seasons

Abstract

Abstract. Pathologic and microbiologic examinations were performed on 1,211 aborted equine fetuses, stillborn foals, and placentas from premature foals in central Kentucky during the 1988 and 1989 foaling seasons to determine the causes of reproductive loss in the mare. Placentitis (19.4%) and dystocia-perinatal asphyxia (19.5%) were the 2 most important causes of equine reproductive loss. The other causes (in decreasing order) were contracted foal syndrome and other congenital anomalies (8.5%), twinning (6.1%), improper separation of placenta (4.7%) torsion of umbilical cord (4.5%), placental edema (4.3%), equine herpesvirus abortion (3.3%), bacteremia (3.2%), fetal diarrhea (2.7%), other placental disorders (total of 6.0%), and miscellaneous causes (1.6%). A definitive diagnosis was not established in 16.9% of the cases submitted. Streptococcus zooepidemicus, Escherichia coli, Leptospira spp., and a nocardioform actinomycete were organisms most frequently associated with bacterial placentitis, and Aspergillus spp. was the fungus most often noted in mycotic placentitis. No viral placentitis was noticed in this series. Dystocia-perinatal asphyxia was mostly associated with large foals, maiden mares, unattended deliveries, and malpresentations. The results of this study indicate that in central Kentucky, the noninfectious causes of equine reproductive loss outnumber the infectious causes by an approximate ratio of 2:1, placental disorders are slightly more prevalent than nonplacental disorders, Leptospira spp. and a nocardioform actinomycete are 2 new important abortifacient bacteria in the mare, the occurrence of contracted foal syndrome is unusually frequent, the incidence of twin abortion has sharply declined, and torsion of the umbilical cord is an important cause of abortion in the mare.Abortion and stillbirth are major causes of equine oughbred, 123 were Standardbred, 40 were American Sadmortality and cause severe economic loss to the equine dlebred, 59 were unspecified, and the remaining included industry. Causes of equine abortion and stillbirth vary Tennessee Walking horse, Arabian, Morgan, Quarter horse, with geographic area and change with time. 1,4,8,13,14,16 Miniature horse, draft horse, and pony. The submissions In early studies, infectious agents were reported as macovered a wide range of gestation ages: 79 were < 180 days, jor causes of equine reproductive loss 4 whereas later 126 were 181-220 days, 135 were 221-260 days, 203 were reports indicated that the loss from noninfectious caus-261-300 days, 538 were over 301 days, and the remaining es, e.g., twinning and stillbirth, surpassed the prevawere of unknown gestation age (Table 1). The submissions were seasonal; the majority of cases were received from Janlence of those caused by infectious agents. 7,8 This report uary to May (Table 2). presents the results from a comprehensive pathologic and microbiologic study on equine abortion and stillBefore gross examination was performed, the foal, allantochorion, and amnion were weighed, and the leng...

Factors Concerning Early Embryonic Death in Thoroughbred Mares in South Korea

“…Late embryonic death can be caused by failure of normal placentation, placental dysfunction, and acute and chronic stress resulting from microorganism infection, endocrine dysfunction, and twin pregnancy [10,27,28,30].…”

Fetal death: comparative aspects in large domestic animals

“…Some important abortive agents are essentially environmental contaminants, e.g. Escherichia coli and Streptococcus zooepidemicus, which, by way of ascending bacterial placentitis, are the most common causes of fetal death, abortion and stillbirth in the mare Acland, 1993;Smith et al, 2003) and account for 10-20% of fetal losses in this species Hong et al, 1993;Smith et al, 2003).…”

“…Small foals with signs of intrauterine growth retardation were associated with a placenta with a low total microscopic area of fetomaternal contact. Other common placental or feto-placental disorders include umbilical cord disorders, such as occluding torsion and long cord/cervical pole ischaemia (Acland, 1993;Hong et al, 1993;Smith et al, 2003).…”

The first reported case of equine nocardioform placentitis in South Africa : case report

“…Typing of a related organism isolated from the lungs and amnion of an aborted foetus revealed it to be closely related to Rhodococcus rubropertinctus 5 . Placentitis caused by a branching, beaded, filamentous nocardioform actinomycete that is Gram-positive and non-acid-fast, and related to Nocardia spp, emerged as a ' new' disease in the late 1980s that causes abortion and stillbirths in Kentucky, USA, and possibly in other areas 6,8,9,17,18 . In the 1998 foaling season in Kentucky, over 100 cases of nocardioform placentitis were diagnosed 17 .…”

“…Most mares show no outward sign of infection, but some mares may show premature mammary development with lactation and occasionally a vaginal discharge 18 . The placentitis is typically focal to focally extensive, chronic or chronic-active, the area involved being covered with thick, tenacious brown mucoid exudate, and the location is predominantly at the base of the horns or at the junction of the horns and the body 6,8,9,17 . This distinguishes it from the typical and most common pathogeneses of ascending placentitis affecting the cervical area of the placenta and from diffuse or multifocal placentitis resulting from haematogenous spread of organisms 17,18 .…”