Behavioral patterns of (co-)grazing cattle and sheep on swards differing in plant diversity

Both botanical composition and the presence of additional grazer species may modify the grazing efficiency and ingestive behavior of ruminants. However, at present, potential effects of interactions between sward diversity and presence of multiple animal species on the grazing behavior of cattle and sheep are poorly understood. The objective of this study was to evaluate the effect of mono- or co-grazing of sheep and cattle, as well as the influence of sward botanical composition (either diverse or grass-dominated swards) on animal behavior patterns in a fully factorial design (α = 0.05). Sixteen core animals (two mono-grazing animals per species on two sward types, plus two co-grazing animals per species on two sward types) were observed simultaneously. The main behavior (grazing, walking, ruminating/resting) of core animals per paddock was recorded repeatedly in scan samplings every ten minutes from 6 to 22 h on twelve observation periods distributed over the grazing seasons of 2009 and 2010. Four daylight quarters of four hours each were differentiated within one observation period. Additionally, bites per minute, bites per step and steps per minute were observed 15 times per core animal on each observation date. Behavioral observations showed that cattle decreased the time allocated to grazing in the presence of sheep (co-grazing management; P ≤ 0.036) and ruminated/rested longer (P ≤ 0.023). However, sward botanical composition had no effect on cattle behavior (P ≥ 0.05). In contrast, sward botanical composition impacted sheep behavior to a greater degree than mono- or co-grazing management (P ≤ 0.05). Both cattle and sheep had a tendency to spend more time grazing and less time ruminating/resting towards the end of the day. In cattle, longer grazing periods were followed by longer ruminating/resting times, whereas sheep varied less in their time spent grazing or ruminating throughout the day. Sheep and cattle responded differently in their grazing behavior to vegetation composition and grazing management showing a potential of the livestock to adapt to a broad range of conditions. The behavior data suggests that livestock performance might gain from co-grazing management. Cattle and sheep behavior should be considered in planning future directions for grassland management and productivity.