Intake and Digestibility of Native and Exotic Grasses Fed Ad libitum to Djallonke Sheep in South Benin

Native (Andropogon gayanus, Panicum maximum and Pennisetum purpureum) and exotic grasses (Brachiaria ruziziensis Panicum maximum cv. C1 and T58) consumed in tropical humid zone were evaluated by estimating their voluntary intake and in vivo digestibility. The measurements were performed with 4 male Djallonke sheep (28 kg LW) fed ad libitum in metabolic cages, during a 10-days in vivo trial, preceded by a 14-days accommodation period. Each grass was studied at 3 stages of development. The samples (distributed grasses, refusals and faeces) were analysed for organic matter (OM), crude fibre (CF), neutral detergent fibre (NDF), acid detergent fibre (ADF), acid detergent lignin (ADL) and crude protein (CP) contents. Voluntary digestible organic matter intake (VDOMI) and voluntary digestible crude protein intake (VDCPI) were calculated (in g kg -1 LW0.75) as synthetic parameters to compare the grasses. The chemical composition of the distributed forages varied significantly (P < 0.001) between species or cultivars and development stages. After 4-5 leaves per tiller stage, CP contents decreased in all species and lowest in native species. Andropogon gayanus was the most lignified species at any stage of development. At the end of the rainy season, Pennisetum purpureum leaves and Brachiaria ruziziensis had the highest CP. For all the grasses, CP contents were higher (and CF contents lower) in the consumed material, compared to the offered forages, showing thereby the high selectivity by the sheep. Dry matter intake, OM and CP digestibility varied greatly (P < 0.001) between forages and development stages with high interactions between these factors (P <0.001). Voluntary digestible organic matter intake and VDCPI were the highest (P < 0.05) for native Panicum maximum and Pennisetum purpureum. There was a relationship between digestibility and intake parameters, and ADL content of the grasses seems to be an important factor determining at least digestibility.

Source de publication: Journal of agriculture, science and technology, 5(4): 513-524.

Contacts du ou des auteurs: S. Babatoundé (sbabatounde@yahoo.fr) , R. Glèlè Kakaï (glele.romain@gmail.com), I. Alkoiret and G. A. Mensah