Nitrogen utilisation and nitrient digestibility of west African dwarf goats fed combinations of dry leaves of Cynodon nlemfuensis, Spondias mombin or Gmelina arborea 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