In Parah 1:3, we read:
כְּבָשִׂים, בְּנֵי שָׁנָה. וְאֵילִים, בְּנֵי שְׁתַּיִם. וְכֻלָּם מִיּוֹם לְיוֹם. בֶּן שְׁלשָׁה עָשָׂר חֹדֶשׁ אֵינוֹ כָשֵׁר לֹא לְאַיִל וְלֹא לְכֶבֶשׂ. רַבִּי טַרְפוֹן קוֹרֵהוּ פַּלְגָּס. בֶּן עַזַּאי קוֹרֵהוּ נוֹקֵד. רַבִּי יִשְׁמָעֵאל קוֹרֵהוּ פַּרְכָדִיגְמָא. [...]
Lambs no more than one year old, And rams no more than two years old. And all these years are reckoned from day to day. One that is thirteen months old is not valid, neither as a ram nor as a lamb. Rabbi Tarfon called it palges. Ben Azzai called it noked. Rabbi Ishmael called it parakhrigma. [...]
We see that there is a 30-day period where the animal is considered neither a lamb nor a ram. This in-between period is not listed when discussing a cow in Parah 1:1.
Does the 30 day in-between period hold also for cows, even though it's not stated? If no, why is there such a distinction?