Ketosis in dairy cattle is characterized by elevated levels of which substance?

• A. Glucose
• B. Lactose
• C. Amino acids
• D. Ketone bodies

Answer: (D)

Ketosis reflects elevated ketone bodies due to fat being mobilized to meet the energy demands of early lactation. When a dairy cow experiences negative energy balance after calving, it breaks down body fat, and the liver converts the resulting fatty acids into ketone bodies (such as beta-hydroxybutyrate, acetoacetate, and acetone). These ketone bodies accumulate in the blood and can be detected in urine or milk, making ketone bodies the hallmark of the condition. Glucose is not elevated in ketosis and may be lower than normal because energy intake and production don’t keep up with demand; lactose and amino acids aren’t elevated markers of this state.