I mentioned earlier on daf 2 that there is a machlokes between the Rabbonon and R. Yishmael the son of R. Yochanan Ben Broka whether yovel begins on R.H. (Rabbonon) or on Yom Kippur (R.Y.B.R.Y.B.B.). Within the opinion of R.Yishmael the braisa learns from the pasuk of וקדשתם את שנת החמשים שנה, that שמתקדשת והולכת מתחלתה. The Rabbonon who disagree use the pasuk to say שנים את מקדש ואי אתה מקדש חדשים. This means that for yovel there is a mitzvah aseh to be mekadesh it, but for Rosh Chodesh there isn't. Rashi explains that the mitzvah of kiddush yovel is - כששנת היובל נכנסה, מצוה על הב"ד לומר מקודשת השנה. There is a requirement on the Beis Din to declare that the year of yovel has kedusha. This Mitzvah is counted in the Chinuch (#332) but the Minchas Chinuch points out that it isn't clear what the mitzvah entails. Rashi both in our gemara and in chumash holds that the Beis Din must be mekadeish it with a formal declaration. Rashi also seems to hold that the kiddush of yovel is done on Rosh Hashana, but the Minchas Chinuch points out that the Sefer HaChinuch seems to hold that it is done on Y.K. The Sefer HaChinuch writes -
ומן הדומה שהיו סנהדרין מתקבצין בקידוש השנה ומברכין עליה לקדש שנים ואח"כ תוקעין בשופר. The fact that he associates it with shofar implies that it is done on Y.K. The Minchas Chinuch explains that it makes sense to do it on Y.K. even according to R. Yishmael who holds that Yovel begins on R.H. because since tekias shofar of Y.K. is me'akeiv, it isn't clear that it will be yovel until the shofar is blown. In truth, it seems from the Sefer HaChinuch both in Mitzvah 332 and more in Mitzvah 330 that the kiddush done by the beis din is NOT a declaration of מקודשת השנה, rather just imposing the dinim of yovel. The Sefer Hachinuch writes in Mitzvah 330 - ואחר כך מקדשין שנת החמשים בשביתת הארץ ולקרות דרור לכל העבדים והשפחות וכל הקרקעות חוזרין לבעליהן. It seems that the Sefer HaChinuch disagrees with Rashi and holds that there is no formal declaration of mekudeshes hashana, but he does write in Mitzvah 332 that they make a bracha. Perhaps the Sefer Hachinuch holds that the kiddush is done through the blowing of the shofar, not with a statemenet of מקודשת השנה.
Aside from the mitzvah to be mekadeish yovel, there is a separate mitzvah that is counted by the Chinuch (#330) to count to the Yovel. The Rambam holds that just as for the Omer we say that there is a mitzvah to count both days and weeks (R.H. 5a), for yovel there is a mitzvah to count 49 years and also to count 7 shemita cycles. Regarding the formality of this count, Tosafos (Menachos 65b) says that perhaps Beis Din would formally make a bracha and count toward the yovel the same way that individuals count sefiras ha'omer. Tosafos in Kesubos 72a also assumes that there is a formal count with a bracha for the Yovel, and asks why there isn't any bracha on the 7 day count for a zavah. It isn't clear from Tosafos whether they hold that a zavah needs to verbalize the 7 day count each day, just that there is no bracha, or whether Tosafos means that there is no verbalization of the count, just a mitzvah to keep track (The Da'as Zekeinim Miba'alei HaTosafos takes for granted that yovel must be counted like sefiras ha'omer and seems to assume that zava is the same, just that there is no bracha). The Minchas Chinuch points out that the Sefer HaChinuch certainly assumes that there is no verbalization of the count of a zavah, just an obligation to keep track. Yet, when it comes to the count of Yovel the Sefer Hachinuch clearly assumes that there is a formal count with a bracha. Even though Tosafos writes דשמא ב"ד סופרין ומברכין על הספירה, the Sefer HaChinuch takes it for granted - וכן היא המצוה שהיו מונין שנה שנה ושבוע שבוע של שנים עד שנת היובל כמו שאנו מונין ימי העומר.
R. Akiva Eiger (Pesakim 29 and 30) had a discussion with his uncle R. Binyomin Eiger about the nature of kiddush of yovel. The Ran holds that Yovel is similar to sefiras zava, not to sefiras ha'omer (the Ran is cited in the Taz 489). R. Akiva Eiger points out that his uncle assumes that the peshat in the Ran is that the sefirah of yovel can be accomplished by the Beis Din through hirhur - merely thinking the number. R. Akiva Eiger himself disagrees and holds that according to the Ran there is no mitzvah at all to count the Yovel. The obligation of the Beis din is just to keep track of when Yovel will be, just as a zavah must keep track of her 7 clean days. Either way, the Ran is disagreeing with Tosafos and the Chinuch.