Do cows with stereotypic tongue-rolling behaviour cope better with their environment?

Area of Science:

• Animal Science
• Ethology
• Veterinary Medicine

Background:

• Stereotypic behaviors, particularly oral ones like tongue-rolling in dairy cows, are indicators of poor animal welfare.
• It is hypothesized that animals engage in stereotypic behaviors as a stress-coping mechanism, potentially leading to lower stress hormone levels.

Purpose of the Study:

• To investigate the relationship between stereotypic behaviors, specifically tongue-rolling, and stress levels in dairy cows.
• To determine if tongue-rolling serves as a coping mechanism for stress in cows.

Main Methods:

• Behavioral observations were conducted on 916 first-lactation Holstein cows over 10 days.
• Cortisol concentrations were measured in hair and saliva samples from 601 cows.
• Dairy Herd Improvement (DHI) data, including milk protein percentages, were collected for 762 cows.

Main Results:

• No significant differences in hair or saliva cortisol concentrations were found between cows with stereotypic behaviors and controls.
• Tongue-rolling frequency was not associated with cortisol concentrations.
• Cows exhibiting extreme tongue-rolling showed significantly lower milk protein percentages, which increased with the frequency of tongue-rolling.

Conclusions:

• Tongue-rolling in dairy cows may not be a direct response to stress, at least as indicated by cortisol levels.
• Extreme tongue-rolling behavior in cows is associated with reduced milk protein content, suggesting a potential link to physiological or nutritional factors rather than stress alone.