Review Paper: Mare Reproductive Loss Syndrome

Veterinary Research Communications, 2008

Journal of Veterinary Diagnostic Investigation, 1997

Brief communications 303 perimental placentitis. Bacterial replication occurs in rough endoplasmic reticulum. Am J Pathol 124:226-237. for Brucella abortus strain RB5. Vet Pathol 33:615. [Abstr.] 4. Chitwood MB, Lichtenfels JR: 1972, Identification of parasitic metazoa in tissue sections. Exp Parasitol 32:461-464. 5. Ewalt DR: 1989, Comparison of three culture techniques for the isolation of Brucella abortus from bovine supramammary lymph nodes. J Vet Diagn Invest 1:227-230. 6. Ewalt DR, Payeur JP, Martin MB, et al.: 1994, Characteristics of a Brucella species from a bottlenose dolphin (Tursiops truncatus). J Vet Diagn Invest 6:448-452. 7. Farrell ID: 1974, The development of a new selective medium for the isolation of Brucella abortus from contaminated sources. Res Vet Sci 16:280-286. 8. Fleischman RW, Squire RA: 1970, Verminous pneumonia in the California sea lion (Zalophus californianus). Pathol Vet 7:89-101. 9. Foster G, Jahans KL, Reid RJ, et al.: 1996, Isolation of Brucella species from cetaceans, seals, and an otter.

Journal of the American Veterinary Medical Association, 2003

D uring the spring of 2001, an epidemic of abortions and stillbirths occurred in central Kentucky. This epidemic of abortions was identified as mare reproductive loss syndrome (MRLS). 1 Although the magnitude of morbidity and mortality of the epidemic has not been completely described, the experience of 2 of the authors (SEB, TWR) indicated that many of these abortions were in early gestation (ie, the first 90 days of gestation). The cause of MRLS remains unknown. Identification of factors predisposing mares to having MRLS would provide clues of potential causal factors and a basis for developing preventive strategies. The objective of the study reported here was to describe results of a case-control study in which mares that had MRLS-associated early-term abortions (ETAs; early fetal losses) were compared with 2 groups of control mares to identify factors that could predispose mares to having MRLS-associated ETAs. Materials and Methods Study population-Veterinarians from 2 large equine clinics a,b in Lexington, Kentucky, were asked to provide a list of farms to which they provided equine reproductive services. Horses that received care from veterinarians from these 2 clinics were the reference population for a study 2 of MRLS-associated late-term abortions; although there was some overlap, the study populations and methods for the late-term abortion study and the study reported here were distinct. For each farm, veterinarians from the 2 clinics also provided rates of pregnancy losses for the farm (defined as the number of mares that were verified as pregnant at 28 days after breeding that subsequently lost the fetus divided by the number of mares verified as pregnant at 28 days after breeding) during 2000 and 2001. The distribution of loss rates for farms was examined, and farms were characterized as high-impact or low-impact. Farms in the upper 33rd percentile of pregnancy loss rate for 2001 or farms that had more than a 3-fold increase in pregnancy loss rate during 2001 relative to 2000 were considered severely affected by MRLS and categorized as high-impact farms. Farms in the lower 33rd percentile of pregnancy losses for 2001 were categorized as low-impact farms. Categorization of farms was made prior to obtaining any data regarding predictors of outcome. At each high-impact farm, 5 mares that had ETAs during the period between February 1 and July 1, 2001, were randomly selected as ETA cases (ETA group). Farm managers were instructed to identify mares that aborted during the first 90 days of pregnancy and that were bred during the period from February to April 2001. When fewer than 5 such mares were available, mares bred during February, March, or April that aborted fetus-Case-control study of early-term abortions (early fetal losses) associated with mare reproductive loss syndrome in central Kentucky

2008

A pregnant 18-year-old Quarterhorse mare presented with fever, anorexia, tachycardia, tachypnea, and gastrointestinal hypermotility at day 68 of gestation. Potomac horse fever was diagnosed based on polymerase chain reaction (PCR) analysis of whole blood and a high antibody titer to Neorickettsia risticii. The mare made a rapid clinical recovery following antibiotic therapy, but aborted 98 days later. Necropsy on the aborted fetus revealed lymphohistiocytic colitis, lymphadenitis, myocarditis, and hepatitis. The placenta was grossly and histologically normal. Formalin-fixed lymph node, thymus, liver, and colon taken from the aborted fetus were positive by PCR for N. risticii DNA. Potomac horse fever is a common disease in horses that may result in delayed abortion. The microscopic lesions in the fetus are characteristic, and the diagnosis can be confirmed by PCR on formalin-fixed tissues.

Acta Veterinaria Hungarica, 2007

A Lippizan mare aborted a male fetus a few days before the expected foaling date without showing any clinical sings. Focal lympho-histiocytic hepatitis in the foal and multiplex focal lympho-histiocytic villitis accompanied by villus necroses and marked hypertrophy of chorionic epithelial cells in the arcades were observed. Elongated nucleated organisms were seen in groups in vacuoles or solitarily located in the cytoplasm of the chorionic epithelial cells. The organisms were in large numbers and often extracellularly in areas of villitis and villus necroses. They were Gram-positive, stained with haematoxylin and eosin (HE), periodic acid-Schiff (PAS) and Giemsa, weakly with Warthin-Starry silver stain but not with Gömöri’s methenamine-silver stain. By ultrastructural and immunohistochemical examinations, the organisms were identified as microsporidia belonging to the genus Encephalitozoon . No Encephalitozoon organisms were detected in the fetal organs. This is the first reported c...

Asian Pacific Journal of Health Sciences, 2014

Abortion in dairy cattle is commonly defined as a loss of the fetus between the age of 42 days and approximately 260 days. Pregnancies lost before 42 days are usually referred to as early embryonic deaths, whereas a calf that is born dead between 260 days and full term is defined a stillbirth Each abortion leads to significant economic loss depending on such factors as the current value of replacement stock, feed and milk prices, and the stage of gestation when the abortion occurs. The diagnosis of abortions often presents a challenge to the herd owner and the herd veterinarian. Although a gradual increase in the abortion rate in a herd may be noted over a period of many years, a sudden and dramatic increase is more commonly seen. For this reason, prompt and thorough action is required when abortions do occur. Well kept records will often be of benefit during the investigation of abortion problems. With the increased use of natural service in many dairy herds, the potential exists for venereal diseases to affect reproductive performance. These diseases have generally been of very minor concern to the dairy industry because of the widespread adoption of artificial insemination. The bacteria may not cause disease symptoms in the cow, the fetus appears to be more susceptible, in large part because of its immature immune system. The resulting growth of bacteria can cause the death of the fetus, which in turn results in it being expelled (aborted) from the uterus. Some laboratory data suggests that these bacteria are the most commonly identified cause of bacterial abortions in dairy cattle.

Journal of Veterinary Diagnostic Investigation, 2004

Arquivo Brasileiro de Medicina Veterinária e Zootecnia, 2017

Arquivo Brasileiro de Medicina Veterinária e Zootecnia, 2005

[Aborto em vacas leiteiras associado a Neospora caninum e a outros agentes infecciosos] Dairy cow abortion associated... Arq. Bras. Med. Vet. Zootec., v.57, n.4, p.545-547, 2005 547 RESUMO Trinta e cinco vacas de rebanhos leiteiros da região Norte do estado do Paraná, com histórico de abortamento, foram pesquisadas sorologicamente para verificar a presença de anticorpos contra Neospora caninum, Toxoplasma gondii, Leptospira spp., Brucella abortus, BHV-1 e BVDV. Vinte e uma vacas apresentaram títulos sorológicos compatíveis com infecção. Todas elas, soropositivas para N. caninum, foram também soropositivas para outros agentes infecciosos, sugerindo a possibilidade de associação desses agentes nos problemas reprodutivos de bovinos, no estado do Paraná. Palavras-chave: bovino, aborto, Neospora caninum, problema reprodutivo

Equine Veterinary Journal, 2014

Reasons for performing study: Nocardioform placentitis in horses is poorly understood, and the development of an experimental model would be of help in understanding the pathogenesis of the disease. Objectives: To investigate whether (1) intrauterine inoculation of Crossiela equi during the periovulatory period or (2) i.v., oral or intranasopharyngeal inoculation of C. equi during midgestation would result in nocardioform placentitis, and (3) before and after mating endometrial swabs present evidence of nocardioform placentitis-associated organisms (C. equi or Amycolatopsis spp.). Methods: In Study I, mares (n = 20) received an intrauterine inoculation of C. equi 24 h after artificial insemination. Endometrial swabs were obtained 24 h post inoculation for PCR analysis. In Study II, pregnant mares (at 180-240 days of gestation) were inoculated with C. equi by intranasopharyngeal (n = 5), oral (n = 4) or i.v. (n = 4) routes. Sixty contemporaneous pregnant mares maintained on the same farm served as control animals. In Study III, privately owned Thoroughbred mares (n = 200) had endometrial swabs collected before and within 24-48 h after mating for detection of nocardioform microorganisms. Results: In Study I, C.equi was identified by PCR in 3 of 20 mares following intrauterine inoculation. Pregnancy was established in 19 of 20 treated mares. There were 2 embryonic losses and one abortion at 177 days of gestation (undetermined cause). Sixteen mares delivered a normal foal and placenta. In Study II, one mare (oral inoculation) aborted at 200 days of gestation (unidentified cause). The remaining mares delivered a normal foal and placenta. In Study III, none of the mares yielded positive endometrial PCR for nocardioform microorganisms. Conclusions: We were unable to induce nocardioform placentitis, and there was no evidence of nocardioform microorganisms in endometrial swabs of broodmares before or after mating. These findings suggest that nocardioform placentitis is not induced simply via the presence of nocardiform actinomycetes and that route, insufficient duration of exposure and dose may play a role in the development of disease. Additional predispositions may also be involved in the development of nocardioform placentitis.