Leaves not liked by herbivores
Cattles actually hate shrubs which are very tough to break and tasteless(for a cow). Some plants they won't touch are:


Lantana urticoides (West Indian shrub verbena), 
Malvaviscus arboreus var.drummondii (wax mallow)
Rhus copallinum (winged sumac)
Viburnum acerifolium (mapleleaf viburnum). 
Morella cerifera (wax myrtle)
Ilex vomitoria (yaupon). 


Source:

https://www.wildflower.org/expert/show.php?id=2108





Lantana urticoides

http://www.wellgrowhorti.com/Pictures/Landscape%20Plants/Shrubs/Web%20Pictures1/M/Malvaviscus%20Arboreus.jpg

Malvaviscus Arboreus

http://www.floridata.com/wallpaper/jpg/Rhus_copallinum_frt800.jpg

Rhus copallinum


(source: naturallandscapesnursery.com)  

Viburnum acerifolium



Morella cerifera



Ilex vomitoria