Oral fluids are the most common and least invasive method of fluid therapy. Animals can be given water, electrolytes, or other fluids orally using a variety of methods, such as a syringe, a bottle, or a gravity-flow system.
Subcutaneous fluids are given under the skin. This is a more invasive method of fluid therapy, but it is less likely to cause complications than intravenous fluid therapy. Subcutaneous fluids can be given using a needle and syringe or a specialized fluid administration set.
Intravenous fluids are given directly into a vein. This is the most invasive method of fluid therapy, but it is also the most effective way to rapidly correct dehydration and electrolyte imbalances. Intravenous fluids can be given using a needle and syringe or a specialized fluid administration set.
Intraosseous fluids are given into the bone marrow. This is a relatively new method of fluid therapy that is used when intravenous access is not possible. Intraosseous fluids can be given using a needle and syringe or a specialized fluid administration set.
The type of fluid therapy that is best for an animal will depend on the animal's condition, the severity of the fluid deficit, and the veterinarian's preference.