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

Havemeyer Foundation Monograph Series No. 3CHANGES OF PGFM, PROGESTERONE AND LHSECRETION PATTERNS IN RELATION TO CYCLELENGTH AFTER CERVICAL MANIPULATION IN MARESJ. Handler, M. Königsh<strong>of</strong>er, H. Kindahl*, H.-O. Hoppen † , J. E. Aurich andC. AurichUniversity <strong>of</strong> Veterinary Sciences, Vienna, Austria; *Swedish University <strong>of</strong> Agricultural Sciences, Uppsala,Sweden; † College <strong>of</strong> Veterinary Medicine, Hannover, GermanyINTRODUCTIONIn horses, early embryonic loss after transcervicaltransfer <strong>of</strong> embryos is tremendous when comparedto o<strong>the</strong>r species. Better results have been obtainedafter surgical transfer. Endocrine changes causedby cervical manipulation may be responsible forthis phenomenon.In non-pregnant horse mares <strong>the</strong> effects <strong>of</strong>cervical manipulation on cycle length werecontroversially discussed in previous studies(Hurtgen and Ganjam 1979; Betteridge et al.1985; Wilde et al. 1989). While Hurtgen andGanjam (1979) were able to shorten dioestrus bydigital manipulation <strong>of</strong> <strong>the</strong> cervix, Betteridge etal. (1985) as well as Wilde et al. (1989) could notfind any release <strong>of</strong> prostaglandins and influenceon oestrous cycle after insertion <strong>of</strong> a transferca<strong>the</strong>ter into <strong>the</strong> cervix. Kask et al. (1997)induced prostaglandin release and shortenedoestrous cycle length in individual mares byperforming sham embryo transfers, whileBetteridge et al. (1985) did not obtaincomparable responses to this manipulation. All<strong>the</strong>se conflicting results might be caused by <strong>the</strong>use <strong>of</strong> different techniques <strong>of</strong> cervicalstimulation.In <strong>the</strong> present study we tested <strong>the</strong> hypo<strong>the</strong>sisthat in non-pregnant mares, a standardisedprocedure <strong>of</strong> cervical manipulation and dilatationcauses an increase in prostaglandin release leadingto disturbances <strong>of</strong> luteal function and a subsequentdecrease in cycle length.MATERIALS AND METHODSMares (n=6) were controlled for cyclic activityduring 5 consecutive oestrous cycles (oestrousbehaviour, transrectal palpation and sonographicevaluation <strong>of</strong> ovaries and uterus). Daily bloodsamples were taken for determination <strong>of</strong> plasmaprogesterone and LH concentrations. Progesteroneas well as LH secretion were calculated as areaunder <strong>the</strong> curve (AUC) for <strong>the</strong> time period fromDay 1–Day 18 <strong>of</strong> <strong>the</strong> cycle (ovulation = Day 0).During <strong>the</strong> second, third and fourth cycle at Days5 and 7 after ovulation, <strong>the</strong> following experimentswere performed in every mare at random order:1) Insertion <strong>of</strong> an embryo flushing ca<strong>the</strong>ter into <strong>the</strong>cervix via speculum; 2) Insertion <strong>of</strong> <strong>the</strong> ca<strong>the</strong>terTABLE 1: Oestrous cycle length, dioestrous length, maximal progesterone concentrations and totalprogesterone release (AUC) in mares after insertion <strong>of</strong> a ca<strong>the</strong>ter into <strong>the</strong> cervix (insertion), afterinsertion <strong>of</strong> <strong>the</strong> ca<strong>the</strong>ter and dilatation <strong>of</strong> <strong>the</strong> balloon (dilatation) and without treatment (control)Treatment Cycle length Dioestrous length Max P4 P4 (AUC)d, mean ± sd d, mean ± sd ng/ml, mean ± sd ng/ml, mean ± sdControl 22.7 ± 2.1 a 18.8 ± 1.8 a 8.5 ± 1.1 a 83.1 ± 15.8 aInsertion 21.8 ± 2.8 17.2 ± 2.2 8.1 ± 1.8 76.6 ± 14.2Dilatation 19.8 ± 1.2 b 16.3 ± 1.4 b 7.8 ± 1.4 b 70.6 ± 14.5 ba,b – different superscripts indicate significant differences (P