HOW HERD LEADERS WEIGH IN

For all the advantages that a herd leader enjoys, there appears to be a potential downside: a higher risk of obesity.

Researchers at the University of Bristol in England recorded social interactions between 203 horses in 42 different herds on continual turnout. A feeding trial was conducted to determine each herd’s social structure by setting out individual buckets of feed and observing which horses displaced others to take their food. Scores were assigned based on how many herdmates a particular horse displaced and how often horses were displaced by others.

Using this data, the researchers calculated a food-contextspecific dominance rank for each horse. The researchers also assigned each horse a body0 condition score.

They found that the more dominant horses generally had higher body condition scores and were more likely to be obese (a score of 7 or higher) than were their lower-ranking herdmates.

Although it’s tempting to assume that dominant horses put on the pounds because they take more food, researcher Sarah Giles, PhD, says this study doesn’t prove that definitively.

“To find this out would require a longitudinal investigation of body condition and dominance status over time in a stable, unchanging herd,” she says. “The reason for their obesity might not be simply down to the amount of food they consume. Being dominant may mean they spend less time moving