Equine abortion and stillbirth in central Kentucky during 1988 and 1989 foaling seasons.
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.
Publication Date: 1993-10-01 PubMed ID: 8286455DOI: 10.1177/104063879300500410Google Scholar: Lookup
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- Journal Article
Summary
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The research conducted studied the cause of reproductive loss in horses in central Kentucky over two years by examining pathologically and microbiologically more than 1,000 aborted equine fetuses, stillborn foals, and placentas from premature foals. The study found the primary causes to be placentitis and dystocia-perinatal asphyxia, among others, with around 20% of cases each, and determined that non-infectious causes outnumber infectious ones by about 2:1.
Methodology of the Study
- The researchers carried out pathologic and microbiologic examinations on 1,211 aborted equine fetuses, stillborn foals, and placentas from premature foals. The examinations were conducted during the foaling seasons of 1988 and 1989 in central Kentucky.
- The goal was to figure out the causes of reproductive loss in mares — female horses that have reached breeding age.
Major Findings
- The two most significant causes of equine reproductive loss were placentitis, an inflammation of the placenta, affecting around 19.4% of the examined cases; and dystocia-perinatal asphyxia, which happens when a foal suffers from lack of oxygen during a difficult birth, in about 19.5% of the cases.
- Other identified causes (in decreasing order of frequency) included contracted foal syndrome and other congenital anomalies (8.5% of cases), 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 or bacterial infection in the bloodstream (3.2%), fetal diarrhea (2.7%), and various other placental disorders (6.0%).
- Around 1.6% of the causes were classified as miscellaneous while in 16.9% of the cases, a definitive diagnosis was not able to be established.
Microbiological Associations
- Certain bacterial organisms – Streptococcus zooepidemicus, Escherichia coli, Leptospira spp., and a specific actinomycete – were identified most frequently in cases of bacterial placentitis.
- The fungus most often observed in mycotic placentitis was Aspergillus spp.
- No viral placentitis was noticed in this study.
Findings Related to Dystocia-perinatal Asphyxia
- Dystocia-perinatal asphyxia was primarily associated with large foals, maiden mares, unattended deliveries, and malpresentations, which are abnormal positions of the fetus at the start of labor.
Some Key Observations
- In central Kentucky, 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, implying that complications involving the placenta are a significant aspect in equine reproductive loss.
- Leptospira spp. and a type of actinomycete were identified as two new important bacteria causing abortion in mares.
- The study observed an unusually frequent occurrence of contracted foal syndrome, where a foal is born with “contracted” or bent limbs.
- The incidence of twin abortion sharply declined — this relates to situations where one or both twins are miscarried during pregnancy.
- The study identified torsion of the umbilical cord, where the cord is twisted, as a significant cause of abortion in mares.
Cite This Article
APA
Hong CB, Donahue JM, Giles RC, Petrites-Murphy MB, Poonacha KB, Roberts AW, Smith BJ, Tramontin RR, Tuttle PA, Swerczek TW.
(1993).
Equine abortion and stillbirth in central Kentucky during 1988 and 1989 foaling seasons.
J Vet Diagn Invest, 5(4), 560-566.
https://doi.org/10.1177/104063879300500410 Publication
Researcher Affiliations
- Livestock Disease Diagnostic Center, University of Kentucky, Lexington 40511.
MeSH Terms
- Abortion, Veterinary / epidemiology
- Abortion, Veterinary / pathology
- Animals
- Female
- Fetal Death / epidemiology
- Fetal Death / pathology
- Fetal Death / veterinary
- Gestational Age
- Horse Diseases
- Horses
- Kentucky / epidemiology
- Placenta / pathology
- Placenta Diseases / pathology
- Placenta Diseases / veterinary
- Pregnancy
- Seasons
- Umbilical Cord / pathology
Citations
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