Which of the following is an effect of high humidity on livestock?

High humidity can significantly impact livestock physiology and behavior, and one of the primary effects is decreased feed intake. When humidity levels are high, animals often experience heat stress because their bodies are less efficient at regulating temperature through evaporation. This heat stress can lead to a decreased appetite as livestock prioritize conserving energy to cope with the uncomfortable conditions instead of focusing on eating. When animals eat less, it can also affect their overall growth and productivity.

The other options do not accurately reflect the typical effects of high humidity. Increased weight gain is unlikely in such conditions since nutritional intake is often compromised. Improved health is not a common outcome; rather, high humidity can contribute to various health issues, including respiratory problems or an increased risk of diseases. Lastly, decreased water consumption is not a typical response to high humidity; animals often continue to drink as needed, even in humid conditions, focusing instead on managing their body temperature. Thus, reduced feed intake stands out as the clear effect of high humidity on livestock.