Horse owners are continually looking for ways to reduce feed costs without disturbing their horses’ health, and a group of French equine nutritionists have some good news in this department: According to recent study results, lactating saddle horse mares on good quality pasture didn’t need to be fed grain to maintain their weight or their foals’ growth.

“Not complementing equine diets with feed would represent a double benefit to horse breeders, on an economic and environmental level,” said Claire Collas, PhD, researcher at French National Institute for Agricultural Research (INRA) in Saint-Genès-Champanelle. Collas presented her work at the 2013 French Equine Research Day, held Feb. 28 in Paris.

In Collas’ study, 16 riding horse broodmares grazed pastures with their nursing foals for four months. During this time, eight of the mares received complementary barley feed daily (60% of energy requirements for lactation), and the other eight received no concentrated feeds. Also during that time, the researchers infected all the mares with roundworms to investigate their ability to fight off infection with the different nutritional inputs. The team weighed the mares and foals regularly and evaluated their body condition and parasite loads throughout the study.

The researchers found that, although both groups of mares spent exactly the same amount of time grazing (15 hours a day on average), pasture-only mares ingested 12% more grass during the entire study period than the complementary feed group. Collas said the pasture-only mares were probably more efficient with their grazing, taking in more grass per mouthful and swallowing faster