94 Feeding behavior and preference of horses fed rhizoma peanut hay

Abstract

Rhizoma peanut has been used as an alternative legume hay for horses; however, feeding behavior and preference of horses fed this hay warrants investigation. This study aimed to evaluate the feeding behavior and preference of mature horses with maintenance requirements fed rhizoma peanut (RP, Arachis glabrata cv Florigraze) hay compared with alfalfa (ALF, Medicago sativa L. cv Legendary XHD) and bermudagrass (CB, Cynodon dactylon L. cv Coastal) hays. Six mature Quarter Horse geldings (593 ± 40 kg; mean ± SD) were randomly assigned to one of the hays in a replicated 3 × 3 Latin square with 21-d periods. After a 14-d diet adaptation, 24-h behavioral observations were conducted using scan sampling. Time spent feeding, at leisure, and at other activities were recorded every 10 min. Number of chews and bites were counted for 5 consecutive 1-min intervals. Preference tests were conducted on d 20 and 21 for a 2-h duration by simultaneously feeding 1 kg (as-fed basis) of each hay in separate trays twice a day (n = 4 observations/period). Horses’ first choice, hay consumption, and number of times each hay was smelled or tasted but left in favor of another hay were recorded. Hays were analyzed for chemical composition before the start of the study. Preference data were analyzed using descriptive statistics, while behavioral data and hay consumption were analyzed using repeated measures mixed model ANOVA. A hay x time of day effect was observed on feeding time ( P = 0.0393), whereas no hay x time effect was observed on time spent at leisure and other activities. When considering the total hours spent on each behavior, horses fed CB spent more time ( P = 0.0092) feeding compared with ALF (11.7 vs. 8.9 h/d) and less time ( P = 0.0037) at leisure compared with both legume hays. Hay type did not affect total time spent on other activities (1.8 ± 0.23 h/d; mean ± SE). Type of hay had no effect on bite rate (10.7 ± 2.2 bites/min), while horses fed CB had lower ( P = 0.0035) chew rate (71 chews/min) compared with RP and ALF (80 and 81 chews/min). Hay consumption was greatest ( P = 0.0425) with ALF (996 ± 17 g as-fed/test; mean ± SE), followed by RP (935 ± 30 g), and lowest with CB (792 ± 18 g). Digestible energy (Mcal/kg DM) in ALF was 2.58, while in RP was 2.53, and CB was 1.94. Crude protein concentrations in ALF, RP, and CB were 22, 16, and 13.6%, non-structural carbohydrates were 11.4, 10.1, and 7.8%, and neutral detergent fiber was 32.9, 40.4, 66.4%, respectively. Horses show preference for legumes, which might be associated with the nutrient profile of the hays. Rhizoma peanut provides time spent on feeding and chew rates similar to alfalfa.