What is a common sign of roundworm infection in young animals?

A common sign of roundworm infection in young animals is diarrhea. Roundworms can lead to gastrointestinal disturbances as they inhabit the intestines, causing irritation and malabsorption of nutrients. This often manifests as diarrhea, which may be characterized by a change in stool consistency or frequency. Additionally, the presence of these parasites can disrupt normal digestive processes, allowing partially digested food to contribute to increased stool output.

While vomiting can occur in cases of severe infection, it is not as definitive of roundworm presence as diarrhea. Weight gain is generally not associated with roundworm infection; in fact, many infected animals may experience weight loss or failure to thrive due to nutrient depletion. Coughing can sometimes occur with respiratory issues caused by migrating larvae in certain types of roundworms, but it is not a primary sign of intestinal infection in young animals. Thus, diarrhea remains the clear indicator of a roundworm infection among the options provided.