78 Effects of maneuvering required maintenance elements to monitor the grazing behaviors of horses

Abstract

Within most equine pasture environments, required elements are not evenly distributed, causing horses to focus their activities around concentrated resources and creating the risk of overgrazing. The objectives of this pilot study were to determine if 1) differing positions of required elements including feed (F), shelter (S) and water (W) affected presence within 23m (P23) and 2) placement of required elements had an affect on the grazing behavior of horses. It was hypothesized that both grazing location and behavior would be affected by altering positions of F, S, and W. Six mature mares were paired and assigned to graze 3 element configurations (CONF; Plots 1, 5 were the same, as were 2, 6 and 3, 4) of F, S, and W within 6 individual pasture plots (∼0.95ha each) in an incomplete random design. The 3 elements were placed 56m apart with CONF tested in duplicate; 3 plots were grazed simultaneously by pairs each for 4 7-d periods with 72hr washouts in between, resulting in duplicate grazing and behavior data sets for each plot. Pastures consisted of varying forage species and mowed to 8cm before subsequent grazing periods or every 10 d. Horses were fed a hay balancer (F) to manufacturer's recommendation at 0715 and 1715 daily with ad libitum access to portable water tanks (W). Shelters were portable manmade structures with canvas tops (S), in which horses had a one week adjustment period to pre-trial. Horses were fitted with global positioning systems (GPS; Trak-4 GPS Tracker, Pryor, OK), logging measurements every 10min. Horses were also visually observed for 3 2-h periods (MOR; NOON; EVE) daily with behaviors recorded every 5 min. Trained observers classified horse behavior as either grazing or other activity. The statistical model included the effect of element positioning, plot, horse, and time and was analyzed via ANOVA to determine if element position affected P23 and/or behavior. There was an effect of element on P23 ( P < 0.01), with F being the most influential ( P < 0.05), as hypothesized. This was likely a result since F was the most limited element. As hypothesized, horses spent more time grazing ( P = 0.05) than other behaviors, especially during NOON ( P = 0.05). Behaviors within plots of identical CONF were not different from each other, indicating horses performed the same behaviors when grazing the same CONF. Moving feeding location frequently may alter grazing behavior, thus distributing animal concentration accordingly and decreasing the risk of overgrazing. Therefore, future studies investigating moving feed only may illuminate new methods of pasture management.