Feeding Behavior of Horses Fed Different Feeds with Free Access or Restricted Access to Hay
Mechanisms controlling satiety and feeding behavior are complex and may involve physical feedback, such as chewing and stomach distention, as well as feedback from nutrients absorbed in the gastrointestinal tract. The study objectives were to examine feed intake behavior when horses are fed concentrates with different energy densities and sources, and to determine how restricting hay intake would alter feed behavior. Eight Thoroughbred geldings (12 ± 3 yr; 596 ± 36 kg) were used in a replicated 4 × 4 Latin square design over four 30-d periods with no washout periods. The concentrate treatments were 3 kg of high-energy, high-starch (HS), 3 kg of high-energy, low-starch (LS), 2 kg of high-fiber pellet (FP), and 0.55 kg of ration balancer pellet (RB). Daily concentrate amounts were split into 2 equal meals fed 12 h apart. Each period consisted of 5 d of feed adaption, 14 d of ad libitum hay access, and 10 d of restricted hay (1.5% BW). Horses were housed in stalls for individual measurement of feed behavior and feed intake. They received group turnout in dry lots for 5 h daily. Horses were observed around meals during d 6–30 of each period to record the time to finish the meal and time to begin consuming hay. Hay intake was recorded daily from d 6–30. Behavior data were analyzed using a repeated measures ANOVA with treatment, period, and hay access as main effects and day as the repeated measure. Ad libitum hay intake was greatest for RB (2.1% BW), followed by FP (1.9% BW), and lowest for HS and LS (1.8% BW; P < 0.05). Overall, the time to finish the meal was slowest for LS, followed by HS, then FP, and fastest for RB (P < 0.05). With restricted hay, the time to finish the meal increased for HS but was unchanged for other treatments (P < 0.05). Following a meal, horses fed RB started consuming hay the quickest, followed by HS, and slowest for LS, with FP not different from HS and LS (P < 0.05). The time to start consuming hay following a meal decreased across all treatments when hay was restricted (P < 0.05). Restricting hay intake shortened the time between finishing a grain meal and consuming hay, suggesting horses had decreased satiety, regardless of concentrate treatment. Despite FP being a smaller meal size, horses fed FP, HS, and LS took the same amount of time to consume hay following a meal, which suggests FP may have characteristics that affect satiety similarly to a larger, more energy-dense meal.
Fowler, A.L., C. Guinard, E.D. Robyn, O. Montgomery, A. Arredondo, I.A. Robinson, and J.D. Pagan. 2025. Feeding behavior of horses fed different feeds with free-access or restricted access to hay. Journal of Equine Veterinary Science 148:105540.