Pasture management strategies to offer optimal sward structures for maximizing intake rate in continuous stocking

Abstract

Understanding herbivore interaction with forage resources is crucial for effective grazing management. This study investigates the impact of sward management strategies on the foraging behavior of sheep under continuous stocking. Italian ryegrass pastures were maintained at an average sward height of 15 cm, which has been reported to be optimal for animal performance. The objective was to assess whether sheep modify their grazing behavior in response to different interventions to maintain the target sward height. Three treatments were applied: 1) put-and-take with weekly stocking density adjustments (P&T); 2) as P&T, plus targeted grazing to areas that exceeded 18 cm, and deferment by fencing in areas where sward height was <12 cm (T&D); and 3) as P&T, plus mowing to 15 cm areas where average height exceeded 18 cm and deferment in areas below 12 cm (M&D). Sheep selectively grazed sward heights between 13–18 cm, which provided the highest intake per unit of grazing time. Regular adjustment of stocking density effectively maintained sward height within the optimal range for grazing. Overall, our results indicated no major changes in short-term behavior variables, daily activities time, grazing patterns, or the sward's height ranges the sheep selected. The results emphasize the importance of managing sward height to optimize animal intake and demonstrate that labor-intensive methods of pasture intervention, rather than simply manipulating animal density over time, do not significantly influence sheep intake or behavior when resources are abundant.