Intramuscular administration for large animals and Intraperitoneal administration for small animals.
Explanation:
The quickest and common parenteral method of administering fluids and electrolytes to a large animal is intramuscular because it results in rapid and uniform absorption of substances due to the abundant vascular supply. Whereas, in small animals such as rats, intraperitoneal administration results in faster absorption into the vasculature that usually akin to intravenous administration.
