Effect of Silvipasture System on Rumen Fermentation and Growth in Crossbred Heifers

Grazing of heifers on natural grassland (Sehima and Heteropogon) without any tree plantation (T₁) was compared with those grazing on grassland planted with Acacia tartilis (T₂) and Hardwickia binata (T₃) with the spacing of 4 x 3m. Two paddocks (20 x 24 m each) rotational grazing, having 15 d interval, was practiced. First phase was comprised of grazing on respective plots but during the second phase of experiment, attempt was made to supplement the grazing through tree leaves and pods. Twelve heifers (four in each group) was allowed to graze for 8h daily. Ammonia N and TWA in rumen fluid were below the minimum concentration except in Acacia pod supplementation group. Total protozoal population ranged from 5.11 x 10⁴ to 8.60 x 10⁴/ml SRL. During first phase, live weight gain were 67,83 and 67 g/d in T₁, T₂ 2nd T₃, respectively, However, negative growth rate was recorded during second phase except in T₂ group. Thus, such silvipasture system can sustain live weight gain of 67 to 83 g/d from mid October in mid December (Autumn) and body weight maintainance was possible on subsequent period with Acacia pod supplementation.