• Treatment and Prevention of Ketosis: In high-producing dairy cows, a negative energy balance around the time of calving can lead to ketosis (acetonemia). Propylene glycol acts as a glucose precursor (gluconeogenesis) when administered orally, providing needed energy and helping to restore normal blood glucose levels. It is typically given as an oral drench or mixed into feed.
• Medication Solvent/Carrier: Propylene glycol is an effective solvent that helps dissolve various medications, particularly in injectable formulations for large animals, which enhances their stability and effectiveness.
• Hydration and Electrolyte Balance: In some cases, it can be a component of oral rehydration solutions to help manage dehydration and provide a quick energy source, such as after surgery or in cases of diarrhea.
• Feed Additive: It is used as a humectant (moisture-maintaining agent) and preservative in some semi-moist pet foods and animal feeds. 

ADMINISTRATION

• Ruminants (Cattle, Sheep, Goats): Propylene glycol is generally recognized as safe (GRAS) for these species when used correctly to manage energy deficiencies. It is primarily effective when given orally, which allows its metabolism in the rumen.
• Dogs and Horses: While generally considered safe for dogs in the small amounts used in some pet foods, large doses can be toxic. Accidental toxicosis has been reported in horses when propylene glycol was mistakenly administered instead of mineral oil.
• Dosage: Proper dosage and veterinary supervision are essential, as excessive administration can lead to side effects like depression, coordination loss (ataxia), or metabolic issues.