Cab Abstracts -- the first place I would look. Has mostly abstracts and some full text
Cab Animal Health and Production Compendium -- Provides a good overview. Includes links to articles in the abstract database as well as CABI Distribution Maps for diseases.
Proquest -- also covers this topic. Here, you can find more full text, and you can also set up a search alert to be informed when new articles are added to the database.
Science Direct -- has good coverage from the scientific research point of view. You will also find full text here, and set up search alerts.