Cattle and Sheep Foraging Behaviour in a Heterogeneous Subtropical Grassland
- Publikations-Art
- Kongressbeitrag
- Autoren
- Diaz Falu, E., Brizuela, M.A., Kurtz, D.B., Giese, M., Asch, F.
- Erscheinungsjahr
- 2012
- Veröffentlicht in
- Resilience of agricultural systems against crises
- Herausgeber
- Tielkes, E.
- Verlag
- DITSL GmbH , Witzenhausen
- Seite (von - bis)
- 27
- Tagungsname
- Tropentag 2012
- Tagungsort
- Göttingen / Kassel
Analysis of foraging behaviour is central to understand grazing distribution and tooptimise grassland management. Our objective was to analyse the effects of environ-mental variables upon foraging behaviour of cattle and sheep co-grazing heteroge-neous grasslands of tall and short grasses. Three cows and ewes grazing in a 130 hapaddock of north-eastern Argentina (INTA Mercedes) were fitted with GPS collarsduring 6 consecutive days in fall, winter, spring and summer 2009. Stocking ratewas 0.67 AU ha-1(cattle:sheep ratio = 3:1). Foraging behaviour was assessed by dailyforaging time, speed, sinuosity and daily displacement. Climate and vegetation werealso characterised. Behavioural variables were analysed by ANOVA, and its relation-ships with environmental covariates were explored. Daily foraging time was similarfor cattle and sheep in all seasons (10.9±1.5 hours). Cattle moved faster than sheepin spring and summer (7.8±1.8 vs. 4.5±1.8 m min−1), showing similar speedsin fall and winter (6.4±1.2 and 5.7±1.7 m min−1). Displacements were predom-inantly straight, irrespective of speed. Daily displacements were higher for cattleduring spring and summer (5439±1979 vs. 3114±1090 m day−1), being simi-lar between herbivores in fall and winter (4122±770 and 3611±896 m day−1).Since there were no variations in daily foraging time, the displacements were a con-sequence of the speed, which was confirmed by its positive correlation (rcattle = 0.77,rsheep=0.71). Cattle walked faster when soil vegetation cover of the tall grasseswas 90 %, decreasing above and below this value. On the other hand, sheep walkedfaster when standing dead biomass of short grasses increased. This could suggest thatboth herbivores increased their speed tending to increase the encounter rate of thepreferred forage as it becomes less abundant. For cattle, lower speeds when soil veg-etation cover decreased below 90 % could reflect a threshold where speed incrementsare not enough to efficiently graze preferred forage, probably causing changes in dietselection to sustain the daily intake. Our results may help to develop criteria based onseasonal herbivore ́s foraging behaviour to optimise grazing management.