Effect of hay nets on horse bodyweight, body condition score, hay usage, and dental health in mature adult horses

Hay nets are a commonly used management practice to increase intake time and reduce hay waste but may impact horse health. The objectives were to compare hay usage, dental wear, and dental conditions between horses fed with (NET) or without (CON) hay nets during a 2-year cross-over study. In September 2021, 13 mature adult horses were blocked by bodyweight (BW) and randomly assigned to the NET or CON treatments for one year. After one year (September 2022), horses switched treatments and the trial concluded in September 2023. Horses were housed in adjacent dry lots with shelter, ad libitum water, and free choice access to round bales with or without hay nets (4.45 cm openings). Blinded dental work, including incisor length measurements and recording of dental abnormalities and conditions, and recording of horse BW and body condition score (BCS) were completed in September 2021, 2022, and 2023. Digital images were taken monthly to determine rostral oral cavity scores (ROCS). Round bales were weighed prior to being placed in the dry lot and the date fed was recorded to calculate hay usage. Significance was set at P≤0.05. Horse BW, BCS, and hay usage were greater in horses consuming hay without hay nets (P<0.05). No differences were observed in incisor length, presence of incisor bevels, ROCS, or dental abnormalities and conditions (P>0.05). These data suggest that hay nets do not result in negative impacts on dental health but can reduce hay usage and help to control horse BW and BCS.