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. 2017;28(2):47-53.
doi: 10.1294/jes.28.47. Epub 2017 Jul 6.

Aborted Fetal Sizes of Thoroughbred Horses in Hidaka, Japan, Between 2005 and 2015

Free PMC article

Aborted Fetal Sizes of Thoroughbred Horses in Hidaka, Japan, Between 2005 and 2015

Harutaka Murase et al. J Equine Sci. .
Free PMC article


The degree of fetal growth restriction has been unclear in equine reproduction. In this study, 2,195 fetuses from 2,137 abortions during 11 seasons were examined to determine the causes of abortion, and fetal size dimensions (crown rump length and body weight) were measured. In total, 900 cases (42.1%) of abortion were identified as caused by viral infection (215, 10.1%), bacterial infection (156, 7.3%), fungal infection (25, 1.2%), circulation failure (406, 19.0%), multiple causes (66, 3.1%), deformity (13, 0.6%), placental abnormality (12, 0.6%), and other causes (7, 0.3%). All viral infections originated from equine herpes virus. Of all abortions, 94.3% occurred between 181-360 days of pregnancy, and the gestational ages at abortion were different based on the causes. Fetal sizes in viral abortions were considerably larger than those due to other reasons. Compared with viral infection, the crown rump length size dimension of fetuses aborted from multiple and fungal infection was affected. In addition, bacterial infection, circulation failure, and unknown causes of abortions also contributed to growth restriction in terms of body weight. In conclusion, the present study showed details of equine abortion and the relationships between causes of abortion and fetal size. Most of the aborted fetuses showed restrictions in their growth. The manifestations of growth restriction were more related to weight than skeletal length.

Keywords: FGR; abortion; causes of abortion; fetal size.


Fig. 1.
Fig. 1.
Comparisons of fetal size among causes of abortion. Body weight was more restricted than crown rump length. An asterisk (*) indicates a significant reduction in comparison with viral abortion within a period. Placental abnormality, deformity, and other causes that explained less than 1% of total abortions were omitted.

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    1. Adams-Brendemuehl C., Pipers F.S. 1987. Antepartum evaluations of the equine fetus. J. Reprod. Fertil. Suppl. 35: 565–573. - PubMed
    1. Akiba T., Takeuchi M., Yamanaka M., Saga N., Shibahara T., Kadota K. 2005. Investigation of causes of equine abortion/stillbirth on 919 cases in the Hidaka district of Hokkaido. J. Jpn. Vet. Med. Assoc. 58: 321–325.
    1. Allen W.R., Wilsher S., Turnbull C., Stewart F., Ousey J., Rossdale P.D., Fowden A.L. 2002. Influence of maternal size on placental, fetal and postnatal growth in the horse. I. Development in utero. Reproduction 123: 445–453. - PubMed
    1. Anzai T., Kamada M., Nakamura M., Yamamoto K., Isayama Y. 1995. Improvement of tube agglutination test for serodiagnosis of equine paratyphoid. J. Jpn. Vet. Med. Assoc. 48: 945–948.
    1. Bailey C.S., Heitzman J.M., Buchanan C.N., Bare C.A., Sper R.B., Borst L.B., Macpherson M., Archibald K., Whitacre M. 2012. B-mode and Doppler ultrasonography in pony mares with experimentally induced ascending placentitis. Equine Vet. J. Suppl. 43: 88–94. - PubMed

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