the teachings of the present inventions are preferably embodied as injectable hormonal preparations and as protocols that use such preparations in order to improve estrus synchronization and achieve a much higher percentage of estrus synchronization as well as the desired preservation of larger corpus luteum sizes . it will be understood by those skilled in the art that the protocols and administered preparations described below in conjunction with the present invention are further facilitated by other techniques known to optimize the benefits of estrus synchronization . these other techniques include the maintenance of adequate nutrition as well as efforts to maintain sufficient overall body scores for the cows and heifers . those skilled in the art will also recognize alternative applications of the compounds and methods of the present invention that may include the preparation of recipient cows for implantation of embryos . for reference in various aspects of the preferred embodiments of the present invention , applicant has developed a preferred formulation for a steroidal hormonal preparation that applicant expects to commercialize under the designation “ supersync ™.” the formulation of the supersync ™ preparation is a combination of an estrogenic compound , a progestin , and appropriate excipients to achieve an injectable form . by an “ estrogenic ” compound , we mean an artificial or synthetic estrogen ( i . e ., a steroidal estrogenic compound ) or derivatives , analogs , or agonists thereof , and any combinations thereof . likewise , by a “ progestin ,” we mean an artificial or synthetic progesterone ( i . e ., a steroidal progestogenic compound ), such as , for example , progesterone , hydroxyprogesterone , medroxyprogesterone , altrenogest , norgestomet , levonorgestrel , or other progestogenic compound , or derivatives , analogs , or agonists thereof , and any combinations thereof . preferably , the estrogenic compound is selected from the group of estradiol 17 - β or estradiol benzoate , or their derivatives , analogs , agonists and the like . to achieve a preparation that is suitable for intramuscular injection , the estrogenic compound and the progestin are compounded with an excipient that preferably combines an anhydrous carrier base ( such as sesame seed oil , cotton seed oil , olive oil ) with one or more excipient solvents . in the preferred embodiments , the excipient solvents are phenylmethanol ( approximately 10 % of the final volume ) and a co - solvent benzoic acid phenylmethyl ester ( approximately 10 % of the final volume ). the excimer is compounded with at least 1 mg / ml estrogenic compound ( preferably 1 . 25 mg / ml ). for a 2 cm3 dose , preferred preparations provide from 2 to 3 mg estradiol 17 - β , which is an amount effective to initiate estrus or , in other words , to reset the follicular wave in a heifer or a cow ( including a non - bovine cow ), and at least 30 mg / ml progestogenic compound ( preferably more than 40 mg / ml and approximately 60 mg / ml ), which has been found to be effective at preserving the corpus luteum intact for five or more days from the date of injection . the maximum amount of estradiol 17 - β should not ever exceed 5 mg per dose . fig3 depicts the methodology of a supersync ™ protocol according to the processes of the present invention . fig4 provides a flow chart describing in a step - by - step manner the methodology of the protocol of the present invention . initially ( step 402 in fig4 ), it is necessary to identify a day zero for the protocol by determining a time period of 45 - 60 days postpartum . starting the protocol no earlier than this time period ensures an involuted uterus . on day zero ( step 404 ), 2 cm3 of the proprietary formulation ( supersync ™) is administered by intramuscular ( im ) injection , preferably in the neck of the animal . the formulation of the proprietary preparation may vary moderately , but in the preferred embodiment includes progesterone and estradiol in a ratio of 60 mg / ml progesterone to 1 . 25 mg / ml estradiol . this proprietary preparation should be administered in the first twelve hours of day zero . the administered preparations described above in the protocol ( supersync ™ protocol ) generally carry out the following functions in the process of estrus synchronization . the proprietary preparation of progestin and estradiol provides a unique simultaneous combination of effects . as indicated above , the progestin component keeps a cow or heifer out of heat and extends the estrous cycle . the progestin / estradiol combination , when administered at day zero , resets the follicular wave in the animal . the prostaglandin ( pg ) prepares for initiation of heat in the animal . estradiol , administered subsequent to prostaglandin , further facilitates ovulation . gonadotropin releasing hormone ( gnrh ), as indicated above , is a hormone that triggers ovulation or starts development of a new follicular wave . lutenizing hormone ( lh ) also triggers ovulation and follicle stimulating hormone ( fsh ) promotes follicular formation . progestin mimics natural progesterone produced by the corpus luteum after ovulation which prepares the uterus for pregnancy and serves to keep the cow or heifer from coming back into heat . estradiol is the most common , and generally considered to be the most effective estrogen hormone . estradiol 17 - β is a naturally occurring hormone that tends to result in the quickest reaction in cows . estradiol benzoate is a possible alternative to estradiol 17 - β . the compositions contained in the proprietary preparation ( supersync ™) administered on day zero , therefore , carry out the important functions towards the goals of the protocol . the progestin helps to preserve the corpus luteum in good condition by shutting down the pituitary function . in essence the progestin ensures that the corpus luteum remains intact . the estradiol functions to reset the follicular wave . specifically , estradiol 17 - β ( e2 ) knocks off the dominant follicle , thereby releasing the ovacyte ( ovulation ), which becomes the egg ( once fertilized ). the ruptured follicle also either becomes the corpus luteum or adds to it ( presuming that a corpus luteum was pre - existing ). the second action step of the supersync ™ protocol ( step 406 ) takes place on day x , where day x is any day from 5 to 8 days after day zero , although it may start as soon as the corpus luteum has adequately redeveloped . on day x , therefore , 5 cm3 of prostaglandin ( pg ) is administered by intramuscular injection , preferably in the neck of the animal , and preferably within four hours of 8 : 00 am and optimally within one hour of 9 : 00 am . in the preferred embodiments , the prostaglandin ( pg ) utilized may be a product marketed as lutalyse ® ( a registered trademark of pharmacia & amp ; upjohn co . of michigan ) which contains the naturally occurring prostaglandin f2α ( dinoprost ) as the tromethamine salt . each milliliter contains dinoprost tromethamine equivalent to 5 mg dinoprost . alternately , in the preferred embodiments , the prostaglandin ( pg ) may be a product marketed as estrumate ® ( a registered trademark of schering - plough of new jersey ) which is a synthetic prostaglandin analogue structurally related to prostaglandin f2α . each milliliter of the colorless , aqueous solution contains 263 mcg of cloprostenol sodium ( equivalent to 250 meg of cloprostenol ). in any case , the prostaglandin functions to put a heifer or cow into heat , thereby disrupting the yellow tissue that makes up the corpus luteum , causing the release of scent and other signs of heat . this process thereby forces ovulation which is the start of complete estrus . the third action step ( step 408 ) typically occurs on day y , which is the day immediately following day x , but should occur within 12 to 36 hours after administering the second preparation wherein 1 cm3 of estradiol is administered , sometime on day y , preferably within four hours of 1 : 00 pm , and optimally within one hour of 1 : 00 pm . this administration of estradiol functions to stimulate the pituitary to release hormones causing ovulation ( i . e ., ovacyte to drop , vulva to swell , etc .). the estradiol used here and elsewhere in the preferred protocols is preferably estradiol 17 - β ( e2 ) or estradiol benzoate , although it should be appreciated that various other natural or synthetic estrogenic compounds , or their derivatives , analogs , or agonists , and any combinations thereof , may be used as less preferred alternatives . it will also be appreciated that , at the risk of marginalizing the benefits of the dosing in the preferred embodiments , alternate concentrations and / or volumes may also be used . for instance , it is appreciated that certain aspects of the invention can be accomplished through administration of other concentrations of the estrogen compound , so long as at least one milligram of estradiol 17 - β , or the biologically functional equivalent dose of an alternate steroidal estrogenic compound , is administered . the final action step ( step 410 ) in the supersync ™ protocol is carried out on day z , which is the day immediately following day y , wherein insemination is effected on day z , preferably within four hours of 2 : 00 pm , and optimally within one hour of 2 : 00 pm . insemination may be carried out with frozen or thawed semen , with actual fertilization typically occurring 4 - 6 hours after insemination . those skilled in the art will recognize that the protocol of the present invention as described above is less labor intensive than those protocols associated with the use of the cidr ® device and may be used on female animals that are genetically ill - suited to cidr ® use ( e . g ., beefmaster cows that typically cannot retain a cidr ® in place ) or individual females that do not tolerate the cidr ® ( e . g ., vaginal scarring from previous pregnancies ). the present invention &# 39 ; s protocol is less traumatic for the cows and heifers , and may be expected to generally maintain better overall health during administration of the protocol than with the cidr ® system . although the protocol and the proprietary preparation have been described in conjunction with a set of preferred embodiments , it will be recognized by those of ordinary skill in the art that certain modifications to the protocols and to the formulation may be made without departing from the spirit and scope of the invention . variations based on the size of the herd and / or the size and overall health of the individual cows and heifers , will become apparent . likewise , variations on the ratio of the compounds making up the proprietary preparation will be apparent to those skilled in the art upon a consideration of the specific applications to which the protocol is directed . in other words , some such variations would be appropriate for use of the protocols in conjunction with natural or artificial insemination versus a similar use of the protocols for embryo implantation . as indicated , these variations , given the basic concepts of the present invention , do not necessarily depart from the spirit and scope of the invention . the results that applicants are able to achieve using the present invention are surprisingly better than the prior art . for instance , although still unpublished , controlled studies have indicated dramatically greater conception rates in virgin dairy holstein heifers using a cidr ®- less protocol where the second preparation was administered on day 6 . similarly , although results may vary with poor controls , estrus synchronization using the present invention has been preliminarily reported to such a degree that more then 90 % of a herd reached estrus almost simultaneously , reportedly with two hours of each other . many other objects , features , and advantages of the present invention will be evident from the remainder of this application in light of a more exhaustive understanding of the numerous difficulties and challenges faced by the prior art , which in turn will be evident to those skilled in the art . in the end , while there are many alternative variations , modifications , and substitutions within the scope of the invention , one of ordinary skill in the art should consider the scope of the invention from a review of the claims appended hereto ( including any amendments made to those claims in the course of prosecuting this and related applications ) as considered in the context of the prior art and the various descriptions of this application . for instance , an alternative embodiment of the present invention involves use of a form of the first preparation ( and in a higher dose ) in donor cows to achieve successful estrus synchronization in preparation for embryo production , collection , and transfer into recipient cows . this embodiment is effective in taurine cows but is especially effective in brahman or other zebu cows . fig5 depicts the methodology of a donorsync ™ protocol according to the processes of the present invention . for this embodiment , one or more of the preferred variations of the day zero preparation from the previous embodiments is used to prepare the donor cow . the injected amount of such preparations , however , is increased — preferably from 30 % to 150 % more than in the prior description . most preferably , the donor cow is injected with the first preparation in a dose of from 3 . 0 to 4 . 5 cm3 and , beginning four days later , a multi - day course of follicle - stimulating hormone ( fsh ) administered intramuscularly twice daily to produce more ovacytes , concluding with injections of prostaglandin to rupture all of the developed follicles . after ovulation , the donor cow is inseminated , usually several times in over a 12 to 24 hour period . thereafter , on day t , typically day 7 , the embryos are collected from the donors and transferred either to the recipients or preserved by freezing .
an injectable preparation of estrogenic and progestrogenic hormonal compounds in an anhydrous excipient injected to synchronize estrus in non - menstruating placental female animals , and a five to nine day protocol to apply the unique preparation to achieve estrus synchronization .