Study: Pasturing Stallions Together is Possible

Study: Pasturing Stallions Together is Possible

While most owners are accustomed to pasturing their stallions alone, study results suggest stallions can successfully be pastured together under certain conditions.


Long-term study results from Switzerland continue to show that under certain conditions, stallions can successfully be pastured together, and the researchers supervising the experiment have issued recommendations on how breeders can implement this practice safely.

In 2010 The Horse described a bold, pioneering experiment at the Swiss National Stud, in Avenches, which dared to pasture five breeding stallions together during their off-season. Handlers were ready with equipment to intervene in the event of conflict, but that was never necessary. The stallions established their own hierarchy in their little “bachelor herd” and lived together in apparent contentment for six months.

Three years later, the national stud farm is still keeping a herd of “bachelors” every year (the herd even grew to eight in the second year), which continue to get along just fine, according to Sabrina Briefer Freymond, DVM, MSc, a researcher at the Swiss National Stud. In fact, she said, even though her research on the herd is now complete and was recently published in the journal PlosOne, the National Stud has made the process “routine” and will likely continue pasturing their stallions together each year.

“None of the stallions ever had to be removed from the herd because of injuries resulting from interactions between them,” Briefer Freymond said.

Briefer Freymond said what's been particularly interesting in the bachelor herd study is observing the stallions' non-aggressive, ritualistic behaviors.

“These behaviors are essential for establishing the hierarchy of the group, and they are far more frequent and numerous than any aggressive behaviors,” she said. “In fact, often these behaviors alone are sufficient to establish the hierarchy between two stallions (without any need for aggression).”

These ritualistic behaviors include noncontact behaviors to maintain social order, including making a display of defecating, sniffing, and squealing. They do not include affective behaviors such as mutual grooming and play.

Aggressive behaviors (defined as any behavior—regardless of whether contact was made—intended to push the other horse away, such as chasing, pushing, or kicking) were infrequent and typically occurred within the first three to four days, Briefer Freymond said. After that, she said, these behaviors might still occur occasionally, but their frequency and severity were similar to what researchers had seen among wild bachelor herds of Przewalski’s horses. Ritualistic behaviors also reduced considerably after the first three to four days, she noted.

Briefer Freymond also reported that stallions that were pastured together the first year showed even fewer aggressive and ritualistic behaviors upon being pastured together in following years. Apparently, they had learned to live together and had acquired a “social experience,” she said.

Interestingly, she noted, as aggressive and ritualistic behaviors dropped off, affective behaviors picked up. The horses seemed to become “friends”—or at least just good pasturemates, she said.

The researchers have also released a short video of the stallions' first two days as a herd, which can be viewed online

The study results are encouraging enough that Briefer Freymond and her fellow researchers are prepared to recommend the practice to breeders.

“We encourage horse breeders with extensive pastureland to keep stallions in stable groups and in adequate densities, particularly for those that are not used for breeding the whole year around,” Briefer Freymond said. “This could potentially improve horse welfare and reduce labor associated with horse management.”

Horse welfare with regard to housing is of particular interest in Switzerland, where it is now illegal to house a horse alone, without another equid. It is, however, legal to keep horses in separate stalls in the same barn, Briefer Freymond said.

“Horses are by nature social animals," Briefer Freymond explained. “Keeping them in a group on pasture is what’s best for their welfare, but the risk of injury is always there. So stabling horses side by side where they can see and touch each other is also a satisfactory way to satisfy their essential needs when group pasturing is not possible.”

While Briefer Freymond’s team recommends breeders group stallions together, they also emphasize following certain precautions when doing so: The horses should know each other before being set free in a pasture together—by having close contact for about two weeks in neighboring stables, for example. Stallions should also be pastured far away from other horses—especially mares—in large pastures with at least an acre of land per horse, and pastures should have extra high fencing to prevent escape, she said.

The study, "Pattern of Social Interactions after Group Integration: A Possibility to Keep Stallions in Group," was published in January in the open-access journal PLoS One

About the Author

Christa Lesté-Lasserre, MA

Christa Lesté-Lasserre is a freelance writer based in France. A native of Dallas, Texas, Lesté-Lasserre grew up riding Quarter Horses, Appaloosas, and Shetland Ponies. She holds a master’s degree in English, specializing in creative writing, from the University of Mississippi in Oxford and earned a bachelor's in journalism and creative writing with a minor in sciences from Baylor University in Waco, Texas. She currently keeps her two Trakehners at home near Paris. Follow Lesté-Lasserre on Twitter @christalestelas.

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