A reddish or grey tint around the eyes in an animal coat is most likely caused by what deficiency?

A reddish or grey tint around the eyes in an animal coat is most likely caused by what deficiency?

• A. Zinc deficiency
• B. Copper deficiency
• C. Iron deficiency
• D. Vitamin A deficiency

Answer: (B)

Copper is required for melanin production in hair because the enzyme tyrosinase uses copper as a cofactor to convert tyrosine into melanin. When copper is deficient, tyrosinase activity drops, reducing pigment synthesis and leading to lighter or altered coat colors. A reddish or grey tint around the eyes can reflect this loss of pigmentation in the periorbital area, where pigment changes can be particularly noticeable. Other deficiencies—zinc affecting skin health but not pigment, iron causing anemia, or vitamin A affecting vision and epithelial integrity—do not specifically disrupt melanin production in the coat in the same way, making copper deficiency the best explanation for that coloration change.

Copper is required for melanin production in hair because the enzyme tyrosinase uses copper as a cofactor to convert tyrosine into melanin. When copper is deficient, tyrosinase activity drops, reducing pigment synthesis and leading to lighter or altered coat colors. A reddish or grey tint around the eyes can reflect this loss of pigmentation in the periorbital area, where pigment changes can be particularly noticeable. Other deficiencies—zinc affecting skin health but not pigment, iron causing anemia, or vitamin A affecting vision and epithelial integrity—do not specifically disrupt melanin production in the coat in the same way, making copper deficiency the best explanation for that coloration change.