Sebum in horse skin contributes to which of the following?

• A. Lubrication for joints, digestion, and respiration.
• B. Waterproofing, moisturizing of skin and hair, and immune defense against harmful microbes.
• C. Hair coloring, scent, and shine.
• D. Cooling and sweating assistance.

Answer: (B)

Sebum is the oily secretion from the horse’s sebaceous glands that coats the skin and hair. This film helps seal in moisture and creates a water-resistant layer, so the skin and coat stay moisturized and less prone to drying. It also contains fatty acids that form part of the skin’s natural barrier, aiding defense against harmful microbes. These roles align with waterproofing, moisturizing the skin and hair, and contributing to immune defense on the surface.

It wouldn’t be correct to say sebum lubricates joints (that’s synovial fluid), assists digestion or respiration, or is primarily responsible for hair coloring or cooling via sweating.