I didn't like this story. I couldn't really relate to either character in the story. While it had several interesting elements, people living on giant lizzards, global terrorism battling against biomass leaving a planet via space elevator, etc... it really felt like the plot was contrived to artifice the supposed "lady and the tiger" situation that wasn't even close to the real story (as others have said). I still don't get how the brother was a "tiger", instead of just a terrorist, since presumably he hasn't been modified like the Tigers of the story.
I then started questioning the entire economic validity of exporting tons of live cattle off-world as a means of food. Given the likelihood of advanced technology enabling hydroponics, genetic manipulation of domesticated animals & plants to grow in low-G, or running rotating space farms would make a more cost-effective solution than shipping beef to and fro entire worlds (and presumably solar systems). Would you then have to recapture the waste material and transport it back down to the surface? At best, it would a very expensive delicacy in space, meaning there probably wouldn't that much going off-world. The only alternate explanation would be if the cattle were meant to be used as breeding stock to start ranches on other worlds. I see a more likely market for raw materials (wood, stone), petroleum, and manufactured items (since factories would presumably be harder to build in space).
How exactly would giant lizzards even work anyway? What would they eat?