Proceedings of the 5th International Symposium on EQUINE ...

Havemeyer Foundation Monograph Series No. 3one reason for <strong>the</strong> increase in uterine blood supply.But <strong>the</strong>re are also o<strong>the</strong>r factors <strong>of</strong> embryonicorigin like prostaglandin E2 (Weber and Woods1993) which could improve uterine blood flow.In conclusion, <strong>the</strong> results <strong>of</strong> this study showthat <strong>the</strong>re is a cyclic pattern <strong>of</strong> uterine bloodperfusion in mares measurable by transrectalcolour Doppler sonography. As in o<strong>the</strong>r species,<strong>the</strong> blood supply <strong>of</strong> <strong>the</strong> pregnant uterus comparedto <strong>the</strong> non-pregnant uterus increases alreadyduring early stages <strong>of</strong> pregnancy. The factorsregulating <strong>the</strong> blood flow in <strong>the</strong> uterine arteries incycling and pregnant mares need to be investigatedin fur<strong>the</strong>r studies.REFERENCESBollwein, H., Maierl, J., Mayer, R. and Stolla, R. (1998)Transrectal color Doppler sonography <strong>of</strong> <strong>the</strong> A.uterina in cycling mares. Theriogenol. 49, 1483-1488.Burdock, E.I., Fleiss, J.I. and Hardesty, A.S. (1963) Anew view <strong>of</strong> interobserver agreement. Pers. Psychol.16, 373-384.Ford, S.P. (1989) Factors controlling uterine blood flowduring oestrous and early pregnancy. In: The UterineCirculation. Ed: C.R. Rosenfeld, Ithaca, New York,Perinatal. Press 113-135.Ford, S.P., Chenault, J.R. and Echternkamp, S.E. (1979)Uterine blood flow <strong>of</strong> cows during <strong>the</strong> oestrous cycleand early pregnancy: effect <strong>of</strong> <strong>the</strong> conceptus on <strong>the</strong>uterine blood supply. J. Reprod. Fert. 56, 53-62.Ford, S.P. and Christenson, R.K. (1979) Blood flow touteri <strong>of</strong> sows during <strong>the</strong> oestrous cycle and earlypregnancy: local effect <strong>of</strong> <strong>the</strong> conceptus on <strong>the</strong>uterine blood supply. Biol. Reprod. 21, 617-624.Gin<strong>the</strong>r, O.J. (1992) Maternal aspects <strong>of</strong> pregnancy. In:Reproductive biology in <strong>the</strong> mare. Ed: O.J. Gin<strong>the</strong>r2nd edn. Cross Plains, Wisconsin: Equiservices, pp291-344.Goswamy, R.K. and Steptoe, P.C. (1988) Dopplerultrasound studies <strong>of</strong> <strong>the</strong> uterine artery in spontaneousovarian cycles. Hum. Reprod. 3, 721-726.Greiss, F., Jr. and Anderson, S.G. (1970) Uterine bloodflow during early ovine pregnancy. Am. J. ObstetGynecol. 106, 30-38.Greiss, F., Jr., Rose, J.C., Kute, T.E., Kelly, R.T. andWinkler, L.S. (1986) Temporal and receptor correlates<strong>of</strong> <strong>the</strong> estrogen response in sheep. Am. J.Obstet. Gynecol. 154, 831-838.Scholtes, M.C., Wladimir<strong>of</strong>f, J.W., van-Rijen, H.J. andHop, W.C. (1989) Uterine and ovarian flow ve-locitywaveforms in <strong>the</strong> normal menstrual cycle: atransvaginal Doppler study. Fertil. Steril. 52, 981-985.Sladkevicius, P.V. L. (1993) Blood flow velocity in <strong>the</strong>uterine and ovarian arteries during <strong>the</strong> normalmenstrual cycle. Ultrasound Obstet. Gynecol. 3,199-208.Weber, J.A. and Woods, G.L. (1993) Influence <strong>of</strong>embryonic secretory chemicals on selective oviductaltransport in mares. Equine. vet. J. Suppl. 15,36-38.11