Grooming behavior reveals social networks among dairy cows

Researchers found age, familiarity and social hierarchies influenced the formation and evolution of social networks among dairy cows. Photo by Gustavo E. Monti
Researchers found age, familiarity and social hierarchies influenced the formation and evolution of social networks among dairy cows. Photo by Gustavo E. Monti

Aug. 4 (UPI) -- By tracking the grooming behaviors of dairy cows, researchers have gained new insights into the formation and evolution of social networks among cows, according to a study published Tuesday in the journal Frontiers in Veterinary Science .

Social grooming among animals is called allogrooming. Among bovine, allogrooming typically involves one cow licking the head and neck of another.


Researchers estimate allogrooming works to strengthen bonds between individual animals, as well as enhance cohesion among the herd. The nuances of these processes, however, are not well documented in cows.

For nearly a month, an international team of researchers from Chile and the United States recorded 1,329 allogrooming events involving 38 different cows at an agricultural research station near Valdivia, a city in southern Chile.

"Our aim was to understand how social networks are formed by cows after they are reunited at the beginning of the milking period, and what factors may influence these changes," lead researcher Gustavo E. Monti said in a news release.

"This is important because cattle form strong bonds, which offer them social support and help them cope with the stressors that occur regularly in dairy cows' lives," said Monti, professor at the Institute of Veterinary Preventive Medicine at the Austral University of Chile.


Analysis of the allogrooming patterns revealed the influence of age and social rank on the formation of social networks among cows. Cows of the same age tended to groom one another more often, and they also tended to groom those they had recently been groomed by, researchers said.

"Our results indicate that licking behavior is important to make friends and to maintain harmony in the herd," Monti said. "That older cows groom more individuals suggests that they take the role of 'peacemakers' in the herd."

Interestingly, the grooming data showed that cows that were active groomers but that failed to show discernible preferences for individual cows became increasingly ignored by the rest of the herd over time, researchers said.

To understand how the relationships between individuals in a group changed over time, the researchers deployed a unique form of social network analysis called stochastic actor-oriented modeling.

Because the bonds formed by cows are important to their emotional well-being and overall health -- and because healthier dairy cows produce more milk -- researchers suggest farmers should pay close attention to the effects of modern farming practices on social networks.

"Farmers should be aware that cows frequently grooming each other is a positive sign that means that those cows get along. On the contrary, if social grooming declines, it may be a sign of impaired welfare," Monti said.


"This new knowledge should be translated into innovative practical strategies that will result in the continued integration of cattle emotional and social needs into management systems," he said.

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