Nitrogen utilisation and nitrient digestibility of west African dwarf goats fed combinations of dry leaves of <i>Cynodon nlemfuensis, Spondias mombin</i> or Gmelina arborea</i> and pap processing waste meal

Abstract

An experiment to evaluate and compare the nitrogen utilization and nutrient digestibility of goat fed a pasture species (Cynodon nlemfuensis) or browse plant leaves (Spondias mombin or Gmelina arborea) based diets was conducted with fifteen (15) growing male West African Dwarf goats aged 7 – 7.5 months and weighing between 6.67 – 7.02 Kg. The animals were randomly divided into three groups of approximately equal mean live weight in a completely randomized design and each group was assigned to one of the experimental diets (A, B and C). The cynodon nlemfuensis based diet served as the control (diet A) while Spondias mombin and Gmelina arborea based diets served as dietary treatments B and C respectively. Each animal was later kept in a metabolism cage equipped with feed and water troughs. Feed (0.40 kg/head/day) was offered at 08.00hrs and water provided ad libitum. Faeces and urine were collected during the sixth week of the experiment and analysed chemically. The dry matter intake (40.25 g/day/W^0.75 kg) of goats fed diet C was significantly higher (P < 0.05) than those on diets A and B. Diet B was the least consumed (34.74 g/day/W^0.75 kg). Animals on diet C recorded the highest Nitrogen intake (4.15 g / head/day) and nitrogen retention (0.44 g /day/W^0.75 kg). Goats on diet C also recorded highest values for the digestibility of DM, CP and OM. Although goats on diet B recorded a higher nitrogen intake (2.90 g/head/day) as against that of diet A (2.27 g/head/day), the least nitrogen retention value (0.12 g/day/W^0.75 kg) was obtained from them. The nitrogen retention value for goats on diet A was 0.17 g/day/W^0.75 kg. The low DM intake and nitrogen retention recorded for goats on diet B was attributed to low palatability / availability of nitrogen due to the presence of high tannin content.

Keywords: Cynodon, Spondias, Gmelina, nitrogen utilization, WAD goats, tannin

Journal of Agriculture, Forestry and the Social Sciences Vol 3(1) 2005: 89-96