Certified GKH Gardening Expert
Holly is a sturdy, salt-tolerant plant, but if your dog urinates repeatedly on the shrub, it can caused the affected areas to turn yellow. If you catch the dog in the act, rinse the urine from the foliage as soon as possible.
Some safe repellents may help discourage your dog from urinating on the shrub. This article will help: https://www.gardeningknowhow.com/plant-problems/pests/animals/natural-homemade-dog-repellent.htm