CRITICAL VALUATION OF PRACTICAL METHODS T O TERM OVULATION AND AI IN RELATION TO ENDOMETRIAL REACTION IN THE MARE

Methodes to predict and induce ovulation as well as artificial insemin ation techniques will be proven in relation to endometrial reaction in the mare. Data concerning follicle growing-rate and consistency in es trous mares and sonographical findings (follicle shape, relation to ov ulation fossa) could serve as reliable parameters for impending ovulat ion in the mare. In A.I.-programs inducing of ovulation is often indic ated; those methodes expect practical effects to term ovulation f fund amental premises are observed (estrous and follicle diameter greater t han or equal to 40 mm; or 3rd day of estrous). Administration of 1.500 I.U. hCG intraveiniously combined with first insemination 24 hours la ter with chilied semen is recommended. Essentially the individual comp onents of the inseminate - spermatozoa, seminal plasma and extender - influence in a different manner character and degree of endometrial re action. intensity of endometrial reaction depends on kind of semen pre servation (frozen > chilled), sperm concentration and volume. Possibly selective mechanism of phagozytosis for structural and/or functional different spermatozoa are existing. Choice of extender should be done in subject to the interval from semen collection until time of insemin ation. Methodes to select spermatozoa in vitro are suitable to improve fertility rates. Reasons of reduced fertility rates when frozen semen is used and mode of operation of equine seminal plasma are in need of further inquiry.