Grete Jørgensen, a researcher with the Norwegian Institute for Agricultural and Environmental Research, told The Local how her joint Norwegian-Swedish research project had hired a professional trainer to teach 13 horses, based at Nypan outside Trondheim, to request or refuse a warm, dry blanket.
"The horses soon learned, using positive reinforcement techniques, that if they want to change their situation -- either to remove a blanket or have one put on -- they should tap one symbol with their muzzle. If they want to remain the same, they tapped on another," Jørgensen said.
Most horses chose to keep their blankets on during days with wind, rain or sleet, with the number of horses requesting the removal of their blankets increasing as the temperature rose and spring brought sunny weather.
Jørgensen said her colleagues Knut Bøe and Cecilie Mejdell, who ran the Nypan project, aimed "to ask horses whether they really need these blankets and rugs or whether they preferred to use their own coats to regulate their body temperature in different weather."
Meanwhile, at a local horse farm on Alstahaug, an island off the coast of north west Norway, Jørgensen offered 16 horses the choice of a heated shelter, an unheated shelter, or staying outside.
"We wanted to investigate how horses from several different breeds would tackle different winter weather conditions," she explained.
She found that the horses did not want to come inside the shelters when the weather was dry, even at very low winter temperatures. When there was rain or sleet, however, the horses were more likely to start muscle shivering or move inside.
"The weather here up on the northern Norwegian coast is quite changeable, so you can have three seasons in one day, and rain and maybe sleet, which is really challenging for the horses to keep up their core body temperature," she said.
Certain Nordic breeds appeared capable of withstanding extreme cold even when it was wet.
"We actually have horses that even in the worst conditions never chose to go inside because the water never gets close to the skin," she explained. "Coat condition is very important and maybe even more important than breed. If the coat is really good, like on a Norwegian breed, then the coat has this cover layer which transports the water off the top of the coat so it never gets wet at the skin."
Jørgensen said that the project would help determine the extent to which the rugs and blankets commonly used in Norway and Sweden were actually helping the animals.
"Many owners have no clue whether their horses need rugs and blankets, so they dress them up both indoors and in the paddock," she said. "Too much use of rugs over time may produce sores and chaffing. The horse is not able to scratch in itchy places and the coat will not develop to its full length."
The joint Swedish-Norwegian project is titled "Impact of Nordic climate and management practices on thermoregulation in the horse".
The Norwegian Project Group comprises Grete Jørgensen and Lise Aanensen from Bioforsk Nord Tjøtta, Knut Bøe from The Norwegian University of Life Sciences (NMBU), and Cecilie Mejdell from The Norwegian Veterinary Institute. The Project is financed through the Swedish-Norwegian Horse Research fund and the Norwegian Research Council.