Bechoros6: 11
זְנַב הָעֵגֶל שֶׁאֵינָהּ מַגַּעַת לָעַרְקוֹב — אָמְרוּ חֲכָמִים: כָּל מַרְבִּית הָעֲגָלִים כֵּן, כָּל זְמַן שֶׁהֵן מַגְדִּילִין הֵן נִמְתָּחוֹת. לְאֵיזֶה עַרְקוֹב אָמְרוּ? רַבִּי חֲנִינָא בֶּן אַנְטִיגְנוֹס אוֹמֵר: לָעַרְקוֹב שֶׁבְּאֶמְצַע הַיָּרֵךְ. עַל אֵלּוּ מוּמִין שׁוֹחֲטִין אֶת הַבְּכוֹר, וּפְסוּלֵי הַמֻּקְדָּשִׁין נִפְדִּין עֲלֵיהֶן.
[If] a calf’s tail does not reach the knee joint —- the Sages said: The growth of all calves is in this manner, as long as they grow they stretch out. Concerning which knee joint did they speak? Said R’ Chanina ben Antignos: Concerning the knee joint that is in the middle of the thigh. By reason of these blemishes a bechor may be slaughtered, and unfit consecrated animals may be redeemed because of them.
Bechoros6: 12
אֵלּוּ שֶׁאֵין שׁוֹחֲטִין עֲלֵיהֶן לֹא בַמִּקְדָּשׁ וְלֹא בַמְּדִינָה: חֲוַרְוָד וְהַמַּיִם שֶׁאֵינָם קְבוּעִין, וְחִטָּיו הַפְּנִימִיּוֹת שֶׁנִּפְגְּמוּ אֲבָל לֹא שֶׁנֶּעֶקְרוּ; וּבַעַל גָּרָב, וּבַעַל יַבֶּלֶת, וּבַעַל חֲזָזִית; וְזָקֵן, וְחוֹלֶה, וּמְזֹהָם, וְשֶׁנֶּעֶבְדָה בוֹ עֲבֵרָה, וְשֶׁהֵמִית אֶת הָאָדָם (עַל פִּי עֵד אֶחָד אוֹ עַל פִּי הַבְּעָלִים); וְטֻמְטוּם, וְאַנְדְּרוֹגִינוֹס — לֹא בַמִּקְדָּשׁ וְלֹא בַמְּדִינָה. רַבִּי יִשְׁמָעֵאל אוֹמֵר: אֵין מוּם גָּדוֹל מִזֶּה; וַחֲכָמִים אוֹמְרִים: אֵינוֹ בְכוֹר, אֶלָּא נִגְזָז וְנֶעֱבָד.
On account of the following [blemishes] one may not slaughter either in the Temple or in the provinces: White flecks or water that are not permanent, or back teeth that were notched but were not uprooted; or an [animal] that has scabs, a wart, or boils; [or] an aged [animal], a sick one, one emitting an offensive odor, one with which a sin was committed, or that killed a person (by the testimony of one witness or by the confession of the owner); an animal of undetermined gender, or an androgynous [animal] —- [one may not slaughter these] either in the Temple or in the provinces. R’ Yishmael says: There is no blemish greater than this; the Sages say: It is not a bechor, and it may be sheared and worked with.