183 Effects of prolonged hay net feeding on equine behavior

Abstract

Feeding strategies are known to affect equine behavior. Hay nets made of rope or canvas are used in the equine industry to slow consumption rates and prevent forage waste. Hay net design varies by material and opening size to restrict or extend forage intake. However, the effect of hay net usage on equine behavior has not been entirely elucidated. A randomized block design 84-d pilot study used 8 mature, stock-type horses (5 mares and 3 geldings with BW and body condition used as blocking factors) to evaluate the impact of hay net use on equine behavior. Horses were randomly assigned to treatment [control (CON) and net (NET)] and individually housed for 16 h/d (1500 to 0700) in 8.22m by 2.74m dry runs. At 0700 and 1500 0.75% BW as-fed coastal bermudagrass hay and a pelleted commercial feed (Equilene® Pellets) at ≤ 0.35% BW was offered. Horses were group housed (n = 4 hd/treatment) with ad libitum access to water and salt between feedings (8 h/d) to allow enrichment and natural behavior. Control horses’ hay was provided in a tub on the ground. Hay for NET was provided in UV-resistant nylon mesh hay nets (Texas Hay NetTM, 14.5 cm2 openings), nets were hung ∼1m from the ground. Each horse was filmed for 1h, bi-weekly during hay consumption and individual behavioral data were collected by 2 researchers to confirm and quantify behaviors defined by an ethogram. Behaviors studiedwere drinking water, startles, maintenance (scratch, stretch, and shake), vocalizations, stall vices (pawing and pacing), aggression, duration of head position while chewing, and frustration with the feeding system (biting at, pinning ears, or kicking out). Data were analyzed using a Chi-squared analysis within R Statistical Program? with expected thresholds for each behavior being based on the projected change for the mean of the treatments. Results were considered significant at P < 0.05. Treatment did not have an effect on forage intake (P = 0.874). Control horses spent more time eating with their heads below their withers when compared with NET (P < 0.001). Observations of startle response were similar to expected values (expected = 4.5, CON = 5, NET = 4). Frustration with the feeding system, pawing, and pacing were increased (P < 0.001) for NET compared with CON. The CON horses exhibited more trips to a water trough (P = 0.035), while NET horses displayed more shaking, scratching, and stretching (P = 0.035). The use of slow-feeder hay nets increased frustration, stall vices, and maintenance behaviors in horses over 84 d, indicating that feeding from hay nets may result in negative feeding habits. These negative habits include kicking and biting at the feeding system, and increased pawing and pacing.