Summary
Twin pregnancies in the mare usually lead to abortion, stillbirth or the delivery
of weak foals. For this reason different reduction methods are applied in studfarm
practice. During the early pregnancy manual crushing of one embryo is the most successful
therapy with high survival rates of the remaining embryo. Depending on gestation length
and the localisation of twins dietary manipulation, transvaginal ultrasound-guided
twin reduction, surgical removal of one conceptus, craniocervical dislocation, placenta
ablation, transabdominal ultrasound-guided twin reduction and induction of abortion
are used to reduce twin pregnancies. This review article describes the factors influencing
the occurrence of twins in the mare, the procedures and the success rates of different
reduction methods.
Key words
mare - pregnancy - twins - ultrasound - twin reduction
Literatur
- 1
Allen W R, Brown L, Wright M, Wilsher S.
Reproductive efficiency of Flatrace and National Hunt Thoroughbred mares and stallions
in England.
Equine Vet J.
2007;
39
438-445
- 2
Becker F, Göllnitz K, Kleinpeter A, Neubauer J, Keindorf H J, Nürnberg G, Kanitz W.
Untersuchungen zur transvaginalen ultrasonographisch geleiteten Reduktion von Zwillingsträchtigkeiten
bei der Stute.
Pferdeheilkunde.
2006;
22
165-168
- 3
Bowman T.
Ultrasonic diagnosis and management of early twins in the mare.
Proc Am Ass Equine Practnrs.
1986;
32
35-43
- 4
Bracher V, Parlevliet J M, Pieterse M C, Vos P L A M, Wiemer P, Taverne M A M, Colenbrander B.
Transvaginal ultrasound-guided twin reduction in the mare.
Vet Rec.
1993;
133
478-479
- 5
Davies Morel M C, Newcombe J R.
The efficacy of different hCG dose rates and the effect of hCG treatment on ovarian
activity: ovulation, multiple ovulation, pregnancy, multiple pregnancy, synchrony
of multiple ovulation; in the mare.
Anim Reprod Sci.
2008;
109
189-199
- 6 Frazer G S. Twins.. Current Therapy in Equine Medicine 5.. Philadelphia: W. B. Saunders;
2003: 245-248
- 7
Giles R, Donahue J, Hong C, Tuttle P, Petrites-Murphy M, Poonacha K, Roberts A, Tramontin R,
Smith B, Swerczek T.
Causes of abortion, stillbirth and perinatal death in horses: 3527 cases(1986–1991).
J Am Vet Med Assoc.
1993;
8
1170-1175
- 8 Ginther O J. Reproductive Biology in the Mare.. Cross Plains (WI): Equiservices;
1979
- 9
Ginther O J.
Twinning in mares: a review of recent studies.
J Equine Vet Sci.
1982;
2
127-135
- 10
Ginther O J.
Effect of reproductive status on twinning and on side of ovulation and embryo attachment
in mares.
Theriogenology.
1983;
20
383-395
- 11
Ginther O J.
Postfixation embryo reduction in unilateral and bilateral twins in mares.
Theriogenology.
1984;
22
213-223
- 12
Ginther O J.
The nature of embryo reductions in mares with twin conceptuses: deprivation hypothesis.
Am J Vet Res.
1989;
50
45-53
- 13
Ginther O J, Douglas R H, Lawrence J R.
Twinning in mares: a survey of veterinarians ans analyses of theriogenology records.
Theriogenology.
1982;
18
333-347
- 14
Ginther O J, Griffin P.
Natural outcome and ultrasonic identification of equine fetal twins.
Theriogenology.
1994;
41
1193-1199
- 15
Govaere J L J, Hoogewijs M K, De Schauwer C, Dewulf J, De Kruif A.
Transvaginal ultrasound-guided aspiration of unilateral twin gestation in the mare.
Equine Vet J.
2008;
40
521-522
- 16
Govaere J J L, Hoogewijs M K, De Schauwer C, Van Zeveren A, Smits K, Cornillie P,
De Kruif A.
An abortion of monozygotic twins in a Warmblood mare.
Reprod Dom Anim.
2009;
44
852-854
- 17 Hoffmann B, Leiser R, Schuler G. Physiologie und Anatomie der Trächtigkeit, Trächtigkeitsdiagnostik..
Reproduktionsmedizin beim Pferd.. Stuttgart: Parey; 2009: 125-154
- 18
Jeffcott L B, Whitwell K W.
Twinning as a cause of neonatal loss in the Thoroughbred.
J Comp Pathol.
1973;
83
91-105
- 19 Jonker F, Parlevliet J, Pycock J, Vos P. Twin reduction in sixteen mares by transvaginal
ultrasound-guided puncture of the embryonic vesicle. Proc Brit Eq Vet Assoc Annual
Congress 1995
- 20 Klewitz J, Heberling A, Ortgies F, Sieme H. Erfolgsraten nach Zwillingsreduktion
mittels transvaginal-ultraschallgeleiteter Fruchtwasseraspiration und transrektaler
craniocervikaler Dislokation. 21. Arbeitstagung FG Pferdekrankheiten 2010
- 21
Klewitz J, Heberling A, Ortgies F, Sieme H.
Erfolgsraten nach transvaginal-ultraschallgeleiteter Fruchtwasseraspiration und fetaler
Punktion bei der Stute.
Pferdeheilkunde.
2010;
im Druck
- 22 LeBlanc M, Lopate C, Knottenbelt D. Pregnancy.. Equine Stud Farm Medicine and Surgery..
London: W. B. Saunders; 2003: 263
- 23
MacPherson M I, Reimers J M.
Twin reduction in the mare: current options.
Anim Reprod Sci.
2000;
60–61
233-244
- 24
Mari G, Iacono E, Merlo B, Castagnetti C.
Reduction of twin pregnancy in the mare by transvaginal ultrasound-guided aspiration.
Reprod Domest Anim.
2004;
39
434-437
- 25 McKinnon A O. Twin reduction techniques.. Current Therapy in Equine Reproduction..
St. Louis: W. B. Saunders; 2007: 357-373
- 26 McKinnon A O, Rantanen N. Twins.. Equine Diagnostic Ultrasonography.. Baltimore:
Williams & Wilkins; 1998: 141-156
- 27
Meadows S J, Binns M M, Newcombe J R, Thompson C J, Rossdale P D.
Identical triplets in a Thoroughbred mare.
Equine Vet J.
1995;
27
394-397
- 28
Merkt H, Jungnickel S, Klug E.
Reduction of early twin pregnancy to a single pregnancy in the mare by dietetic means.
J Reprod Fertil Suppl.
1982;
32
451-452
- 29
Merkt H, Jöchle W.
Abortions and twin pregnancies in the Thoroughbreds: rate of occurrence, treatments
and prevention.
J Equine Vet Sci.
1993;
13
690-694
- 30
Merkt H, Jöchle W.
More twin pregnancies as seasons progresses.
J Equine Vet Sci.
1999;
15
614-617
- 31
Morris L H A, Greenwood R E S, Allen W R.
Transvaginal ultrasound-guided reduction of twin conceptusses in the mare.
Proc Int Conf Equine Reprod.
1999;
15
614-617
- 32
Pascoe R R.
Methods for the treatment of twin pregnancy in the mare.
Equine Vet J.
1983;
15
40-42
- 33
Pascoe D R, Pascoe R R, Hughes J P, Stabenfeld G H, Kindahl H.
Management of twin conceptusses by manual embryonic reduction: comparison of two techniques
and three hormone treatments.
Am J Vet Res.
1987;
48
1594-1599
- 34
Pascoe D R, Stover S M.
Effect of surgical manipulation, placental fluid and flunixin meglumine on fetal viability
and prostaglandin F2α release on the gravid uterus of mares.
Am J Vet Res.
1989;
50
1505-1511
- 35
Platt H.
Etiological aspects of perinatal mortality in the Thoroughbred.
Equine Vet J.
1983;
5
116-120
- 36
Rantanen N.
Ultrasound guided fetal cardiac puncture for twin reduction in mares.
Proc Am Med Soc Therio.
1990;
64-65
- 37
Rantanen N W, Kincaid B.
Ultrasound guided fetal cardiac puncture. A method of twin reduction in the mare.
Proc Am Assoc Equine Prctnrs.
1988;
34
173-179
- 38 Ricketts S, Barrelet A, Whitwell K E. Equine abortion.. Reproduction Foaling. Part
2: Fetal and Neonatal Aspects, EVE manual.. Newmarket: Veterinary Journal; 2003: 18-21
- 39
Riera F L, Roldán J E, Hinrichs K.
Patterns of embryo recovery in mares with unilateral and bilateral double ovulations.
Anim Reprod Sci.
2006;
94
398-399
- 40 Rooney J R. The fetus and foal.. Autopsy of the Horse.. Baltimore: Williams & Wilkins;
1970: 120-134
- 41
Squires E L, McClain M G, Ginther O J, McKinnon A O.
Spontaneus multiple ovulation in the mare and its effects on the incidence of twin
embryo collections.
Theriogenology.
1987;
28
609-613
- 42
Veronesi M C, Battocchio M, Faustini M, Gandini M, Cairoli F.
Relationship between pharmacological induction of estrous and/or ovulation and twin
pregnancy in the Thoroughbred mares.
Domest Anim Endocr.
2003;
25
133-140
- 43
Veronesi M C, Faustini M, Villani M, Kindahl H, Galeati G, Batocchio M.
Plasma concentrations of 15-Ketodihydro- PGF2α, cortisol and progesterone during manual twin reduction in Thoroughbred mares.
J Vet Med.
2005;
52
411-415
- 44
Wolc A, Bresinska A, Szwaczjowski T.
Genetic and permanent environmental variability of twinning in Thoroughbred horses
estimated via three threshold models.
J Anim Breeding Genetics.
2006;
123
186-190
- 45
Wolfsdorf K E.
Management of postfixation twins in mares.
Vet Clin N Am Practnrs.
2006;
22
713-725
- 46
Wolfsdorf K E, Rodgerson D, Holder R.
How to manually reduce twins between 60 and 120 days gestation using cranio-cervical
dislocation.
Proc Am Ass Equine Practnrs.
2005;
51
284-287
Dr. Jutta Klewitz
Klinik für Pferde
Reproduktionsmedizinische Einheit der Kliniken
Stiftung Tierärztliche Hochschule Hannover
Bünteweg 15
30559 Hannover
Email: jutta.klewitz@tiho-hannover.de
