The farms "east of 99" are further south, down between Elk Grove and Galt (unless you mean the ubiquitous dairies in the south Sac/Laguna area

). I should know, I drive that stretch every day to work. A bloodhound couldn't smell the cows from there at the airport.

To the north are homes in the Natomas area and agricultural fields, but no cows to speak of.
And no, there are no cows "directly east of the airport" - that area also is agricultural, but without animals. Do a google search for Sacramento, CA, click on the map (first item listed), pan/zoom to the northwest as needed, and do a Street View on Powerline Road just next to the airport. Not a cow to be seen, and no fences to keep cows in if they were there on occasion, which they are not. Do the same along Elkhorn or Elverta. Again, no cows.
And, since the prodominant wind direction is from the west with our Delta Breezes, cows to the east wouldn't affect the airport anyways. But west of the airport is the Sutter Bypass, an agricultural flood zone without animals either. So I don't know where you think there are cows near the airport, but there really are not.