Feed intake and digestibility by sheep of natural vegetation in the riparian land of lake Naivasha, Kenya

• Digestibility of DM and OM and of fibre fractions decreased with increased land use duration.
• Increased land use duration leads to increased forage fibre and reductions in Ca, K and P content.
• Increased land use duration did not affect DM intake.
• Lake Naivasha riparian pastures can, with nitrogen supplementation, be a good feed resource for ruminants.
• Use of chronosequence approach provides an analytical framework to study effects of land use duration on feed quality.

Riparian lands are key dry season feed resource areas in Kenya. The feed quality of pastures of Lake Naivasha riparian has previously not been studied. Chronosequence positions corresponding to 30, 25, 20, and 15 years of land use and four transects perpendicular to the chronosequence representing observed soil differences were selected, intersections forming forage sampling plots. A 4 x 4 Graeco-Latin square design experiment using sheep was conducted to determine voluntary intake, digestibility, and effects of land use duration and soil type. The sheep were housed in metabolic cages and fed for ad libitum intake. Feed intake and faecal output were recorded and samples taken for analysis. Land use duration did not affect dry matter (DM) and organic matter (OM) intake (DMI and OMI). The digestibility of DM and OM and of fibre fractions decreased with increased land use duration. Increased duration of exposure from lake recession and land use leads to increased forage fibre, reduced digestibility of DM and fibre fractions and reductions in Ca, K and P content but did not affect DM intake. Lake Naivasha riparian pastures would provide sufficient energy and can, with nitrogen supplementation, be a good feed resource for ruminants. Use of chronosequence approach provides an analytical framework to study effects of land use duration on feed quality.