Which of the following is a sign of inadequate hydration in livestock?

Dry mucous membranes are a clear indicator of inadequate hydration in livestock. When an animal is dehydrated, the body's fluid levels drop, leading to a decrease in moisture content in various tissues. Mucous membranes, including those in the mouth and nose, typically become dry and sticky, making it a straightforward visual cue for assessing hydration status.

In contrast, increased energy levels and increased appetite might indicate good hydration or health. Regular urine output usually reflects adequate hydration since animals need sufficient fluids to produce urine. Thus, monitoring mucous membrane moisture is vital for assessing hydration status and overall health in livestock management.