English: “And if…” — this continues the prior subject. And why was a break made? To give Moshe space to contemplate between one passage and the next.
In Sifra: The vav of “ואם” links the flock-olah rules to the cattle-olah that precedes. The paragraph break is pedagogic: even Moshe needed a pause to absorb each unit before the next was spoken.
The flock section is not a separate topic but an extension of the cattle olah; the Torah’s paragraphing models deliberate, paced reception of successive teachings.