Why did Yaakov send the animals in groups with breaks in between?
Rashi: He did this to maximize the effect of the gift, to surprise Esav with its magnitude 1 and satisfy his greed.
Seforno: So that Esav should take note of the fact that he had sent him couples in a way that was most beneficial to him (as explained in 32:15-16), 2 inasmuch as the gift would increase rapidly. 3 Moreover, he instructed them to leave a space between the groups, 4 to avoid the animals jumping from one group to the other, thereby losing the desired effect.
Rashbam: He sent the gift in a way that is more dignified.
Hadar Zekenim says that there was Mil (about a kilometer) in between. Rashi says that there was a day's journey (40 Mil) or less in between.
Refer to 32:15:1:1*.
As Yaakov specifically intimated, when (below, 33:11), he refers to the gift as 'a blessing' (Seforno).
Ha'amek Davar: Also initially, each species was by itself, lest improper slaves mate animals with a different species.
QUESTIONS ON RASHI
Rashi writes: "Each flock by itself - [I.e.] each species separately." Why explain this way?
Gur Aryeh: The verse implies that there were already many distinct flocks; and that Yaakov did not mix them, but rather sent each separately. They only way they could have already been distinct, is in terms of species. 1
But perhaps they were distinct because one flock was speckled, and one flock was spotted? (CS)
Rashi writes: "'Pass before me' - [By] one day's journey or less." How does Rashi know this?
Gur Aryeh: Yaakov could not have meant that he was following directly behind them, for Yaakov would still camp for the night before meeting Esav (32:22). He also does not mean they should go more than a day in advance, for "before me" implies what a person can reach in one day's journey, without pausing for the night.