Check the listing for details. Animal Essential SENIOR BLEND (Immune System) Dog Cat 1 ounce. Color: Multi-colored, Condition: New. Listed at 20.03 USD. Animal Essentials Senor Blend was formulated for your pets to strengthen functions in the nervous, digestive, circulatory, and immune systems of older dogs and cats. Often used as a tonic in animals with diminished kidney function. It is a glycerin-based formulation for both cats and dogs. All Animal Essentials tinctures are formulated by leading veterinarians and herbalists. These veterinarians are intimately familiar with the needs and sensitivities of cats and dogs. The herbs Animal Essentials uses are selected from only the highest quality, certified organic or wild-crafted sources found in North America. Animal Essentials naturally balanced herbal blends have a sweet flavor that appeals to most dogs and cats.