111 Grazing behavior of horses managed on legume-grass mixed pastures

Abstract

Abstract Intercropping legume into grass pastures improves pasture quality and decreases the need for nitrogen (N) fertilizer, while providing a more heterogenic grazing environment. This study aimed to evaluate the effect of rhizoma peanut (RP, Arachis glabrata) intercropped into bahiagrass (Paspalum notatum) pasture on horse grazing performance. Unfertilized bahiagrass (UNF) with no N fertilizer, bahiagrass with 120 kg N ha-1 (FER), and bahiagrass with RP and 30 kg N ha-1 (RP) pastures were evaluated using twelve mature Quarter Horses continuously stocked for 84 days in a randomized block design with two blocks. Grazing, activity and leisure behaviors were recorded every 10 minutes for 24 hours on day 35 and 70 using scan sampling. Chew (CR, chew/min) and bite (BR, bite/min) rates were counted for five consecutive 1-min intervals on days 36 and 71. Data were analyzed using a repeated measure mixed model ANOVA. Pasture did not affect (P > 0.05) total time spent on grazing (13.57 ± 1.81 h, mean ± SD), leisure (9.64 ± 1.64 h), and activity (0.79 ± 0.60 h). Pasture x time of day interaction (P < 0.05) was significant for grazing, leisure and activity. Horses grazing FER spent more time grazing between 1100 and 1700 h, whereas horses grazing RP spent more time grazing between 2300 and 500 h when compared to horses grazing FER. Horses grazing FER spent more time in leisure between 2300 and 700 h. No day or pasture effects were observed for BR (30.8 ± 6.3 bites/min, mean ± SD), but a pasture x day interaction was observed for CR. On day 36, CR of horses grazing FER was similar to RP (50.8 and 53.8 chews/min), but lower than RP on day 71 (41.4 and 61.3 chews/min). Intercropping RP into bahiagrass pastures does not affect total grazing, leisure and activity time of horses.