Milk by-products in animal feeds are primarily used as which type of supplement?

• A. Protein supplements.
• B. Vitamin supplements.
• C. Mineral supplements.
• D. Fiber supplements.

Answer: (A)

Milk by-products are valued primarily for their high-quality, highly digestible protein with a strong essential amino acid profile. In feeds, this makes them very effective at meeting livestock protein requirements, especially when plant-based proteins are limited in certain amino acids like lysine or methionine. While these by-products do provide minerals and some energy from lactose, their main role is to boost the diet’s protein content with a high biological value, which supports growth and performance. That combination—high-quality protein with good digestibility—is why they are considered protein supplements, more so than vitamin, mineral, or fiber supplements.