64 A preliminary study: Effect of hay nets on horse hay usage, dental wear, and dental conditions in mature adult horses

Abstract

Hay nets are a commonly used management practice to decrease intake rate and reduce hay waste but can create unnatural foraging conditions that may impact horse health. The objectives of this study were to compare hay usage, dental wear, and dental conditions between horses fed with or without hay nets. Researchers hypothesized horses consuming hay from hay nets would use less hay and have no differences in dental health compared with horses fed without hay nets. In September 2021, 13 mature adult horses were blocked by bodyweight (BW) and randomly assigned to a hay net or no hay net treatment for one year. Horses were housed in adjacent dry lots with shelter, ad libitum water, and free choice access to grass round bales with or without hay nets (4.45cm openings) depending on assigned treatment. Blinded dental work was completed for all horses by an equine veterinarian and dentist in September 2021 (baseline) and 2022 (conclusion of year 1, start of year 2) and included measurements of incisor and canine lengths and recordings of dental conditions before and after dental work. After dental work in 2022, horse groups switched treatments. Horse BW, body condition score (BCS), and softtissue damage on their gums or lips were assessed and recorded monthly. Round bales were weighed before being placed in the dry lot and the date fed was recorded to calculate hay usage (intake and waste). Data were analyzed using PROC MIXED in SAS with significance set at P ≤ 0.05. Horse BW, BCS, and hay usage were greater in horses consuming hay without hay nets (P ≤ 0.05). When pre- and post-length of incisors were evaluated, no differences were observed between treatments (P > 0.05). Incisor length between 2021 and 2022 increased by 3.77 and 3.19mm for horses feeding from no hay net and a net, respectively. Presence of incisor bevels after one year and notation of monthly soft tissue damage did not differ between treatments (P > 0.05). These preliminary data suggest that hay nets do not result in negative impacts on dental health over one year but can significantly reduce hay usage and help control horse BW. This study is ongoing and will be completed in September 2023.