When looking for a source of hay, horse owners and veterinarians often evaluate quality through the senses, including smell, feel and visible appearance of color. A Swiss study looked at how well human selection stacks up against a horse’s preference for palatability [Holzer, S.; Herholz, C.; Tanadini, L.G.; et al. Hay preferences in horses versus selection by their owners. Livestock Science (2022), doi: https:// doi.org/10.1016/j.livsci.2022.1048].
Researchers offered three different hays to three groups of 12 horses each over a six-day period. The final preference test was on the sixth day. One group consisted of French mountain horse stallions. Another group consisted of Icelandic horses (mostly geldings and two mares). The third group was comprised of warmblood horses (mostly geldings and three mares). The hay choices were different in texture, color, odor and nutrient content.
Researchers noted the horses’ initial preference on Day 1. Days 2-5 were adaption days, and Day 6 was the final preference day. Three individual boxes containing 6.6 pounds of each hay were offered simultaneously for the final preference test. The horses consumed around 1⁄4-1⁄2 pound of hay over 30 minutes.
Horse Hay Preference
Sixty-nine percent of horses preferred type B hay. Thirty-one percent preferred type C, and no horse selected type A hay. Crude protein content and leaves were moderately correlated with horse preference. Their preferred selections were higher in quality, energy and protein than Type A hay. They also had more leaves and fewer stems.
Human Hay Preference
Horse owners assessed two pounds of each hay via sight, touch and smell. They made their choices based on which hay type they thought could provide optimal nutritional needs for their horses.
Interestingly, 42% of owners with easy keepers such as French mountain and warmblood horses preferred Type A hay to meet “nutritional requirements.” It seemed to have less energy and quality based on yellow color and higher fibrous content. Type A hay was the type that all the horses avoided.
Type B hay was green, soft and flexible, with a strong aromatic odor. It was the choice of hay for half of the Icelandic owners. Nearly half of Icelandic and warmblood owners selected Type C—fine stems, green, excellent aroma—compared to 25% of the stallion owners. In summary, the horses preferred hay “with a leafy structure rich in energy and protein.” All the horses avoided stemmy hay of a straw-like texture low in energy and protein.
“Among the owners, 42% preferred the hay type completely avoided by the horses. Approximately 30% chose one of the two other hay types rich in energy and protein as the best hay quality for their horses’ assumed nutritional requirements.”