Foraging behaviour and dry matter intake by lambs in a silvopastoral system

Abstract

Dry matter intake, nutritional contribution of forage to the diet and lambforaging behavior were assessed in a silvopastoral system. Twelve Pelibuey female lambs(6.3 months of age, 23.74±3.5 kg live weight), were randomly assigned to two treatments:pastures ofDigitaria eriantha(monoculture) or pastures ofD. erianthaandGuazumaulmifolia(silvopastoral). During a 15 day period, lambs foraged individually in 20.14 m2paddocks each day; time spent grazing and browsing were assessed by scan sampling;dry matter intake was estimated (day 11-15), using the chromic oxide (Cr2O3) method,and metabolizable energy (ME) and protein (CP) ingested by the lambs were estimated.Data analyses were performed using a complete randomized design (dry matter intake) anda repeated-measure design (ME and CP, foraging time) with factorial treatment structureof season (windy and dry) and pasture (monoculture and silvopastoral). Voluntary intake(season*treatment interaction, p = 0.015) was lower in the windy-silvopastoral treatment(448.5±38.2 g day−1) than in the other treatments (625.8±38.2 to 680.5±38.2 gday−1). The contribution of ME (719.7-1190.2 kcal·day−1) and CP (53.7-100.7 g day−1)was low to cover the lamb requirements in all treatments, because forage availability anddry matter intake were low. Lambs dedicated from 6.65±0.26 to 7.50±0.26 h to foraging;time spent grazing was longer that browsing in the silvopastoral system (p < 0.0001). Thetime dedicated to foraging, intake, and nutritive quality of forage from in both pasture typesdid not provide sufficient nutrients and energy during any season for maintenance of thelambs.