You only need two tables, tblSpecies and tblBreed.
Dog, cat, horse etc can be obtained through the relationship between species and breed. Not only is this method cleaner and more effective, but it solves this "table switching" issue you're looking at right now.
ok, I have one table now with all of the Breeds in it. The columns are ID species and breed. It is called tblBreed. The other table is tblSpecies, and it has ID and Species. Species in both tables is related.
I still can not figure out how to have the second combo box (cmbBreed) show only the breeds related to the choice picked using cmbSpecies.
You can set up the relationship between the two tables were the SpeciesID is the primary key in the TblSpecies and SpeciesID is the foreign key in the TblBreeds. You can easily do this using the Relationships button on your main menu bar.
Then write a query to
WHERE forms!YourForm!SpeciesComboBox = BreedsField
Then use the query to populate the second combo box.
Hmmm..I haven't tried it, but I believe that you will have to run the query on the OnChange of the first ComboBox.