"A Guide to Plant Poisoning of Animals in North America" by Anthony P. Knight and Richard G. Walter as a book and CD.
Though some of the text is written with the specialist in mind, it is accessible to lay people as well. I have found both the book and the CD invaluable in identifying toxins in plants, signs of poisoning, and medicines or techniques to combat the poison. You can order it at Amazon.com.
"Toxic Plants of North America" by George E. Burrows and Ronald J. Tyrl.
Again, this was written with the specialist in mind, but you can work your way through it. At over $300 new at Amazon.com it may seem expensive, but that's a lot less than the price of a healthy heifer. There is a paperback edition at a third the price, but it has less than a third of the information contained in the hardcover edition.
USDA Forest Service Plant Information Pages - This web site has an amazing quantity of information on invasive species, sometimes on their palatability, and responses to a variety of management tools. It is backed with loads of citations. To use this site, select forb, graminoid (grass), shrub, etc. to go to a page where the plant is represented by it's latin name - the first three letters of the first word and then first three letters of the second word in the title. Click and read!.
EBIPM - Ecologically-Based Integrated Pest Management - A USDA-ARS project focused on managing cheatgrass and medusa head in the Great Basin.
Targeted Grazing: A Natural Approach to Vegetation Management
This site is provided by the University of Idaho and shares results of published research and on-the-ground projects related to using livestock to accomplish landscape goals such as weed management, fire risk reduction, and restoration. A full handbook on Targeted Grazing is available for dowload on the site.
"Moving 'Em: A Guide to Low Stress Animal Handling"
Here's something well worth the investment! Dr. Burt Smith has put together excellent materials for those interested in learning and practicing low-stress animal handling. You can purchase his book at Amazon.com. I really like his video, "Basic Herding." I don't know if it is still available. to find out, contact Burt or Martha at: Graziers Hui, 5000 W. 350 N., Greencastle, Indiana 46135, (765)739-6565, firstname.lastname@example.org
BEHAVE.net - The BEHAVE consortium (Behavioral Education for Human, Animal, Vegetation and Ecosystem Management) has spent over two decades studying diet selection in animals and was my initial resource for my training steps.