Opinion#1: This is similar to the Pasuk, "And Shalishim on all of it" (Shemos 14:7). This is also like the Pasuk, "A Meshulash calf and a Meshulah ram" (Bereishis 15:9). This (and these Pesukim) means healthy and good.

Opinion#2: Some say this means the third calf out of the mother's stomach (i.e. womb).

Question: This cannot be, as we say in Sanhedrin that they (Amoraim) would create an Igla Tilsa (using Sefer Yetzirah).

Opinion#3: The explanation is also unlike the one who explains that the calf grew one third of its growth.

Question: In Shabbos (136a) the Gemara states that he made them an Igla Tilsa on the seventh day. This means on its seventh day of its life (when it would clearly not yet have been one third grown).

Implied Question: The city was not yet given over until Titus came. (Note: Why, then, did Rebbi Yochanan say it was given over to Vespasian?)

Answer: Being that Vespasian had already besieged the city for three years and there was a famine, it was as if the city had already been given to him.

Explanation: This happened in order to show that the destruction of the Beis Hamikdash was difficult (so to speak) for Hash-m.

Implied Question: He did not become a Treifah. (Note: Tosfos is explaining that there is no question from this incident on the opinion that a Treifah does not live twelve months (see Chulin 57b), as he did not become a Treifah. Why didn't he become a Treifah?)

Answer#1: The mosquito went through his nose and did not pierce the casing (of the brain).

Answer#2: Additionally, there is a difference between a person being a Treifah and an animal being a Treifah, as is explained in (Tosfos in) Eiruvin (7a, DH "k'Gon" in the parentheses).