Effects of varying dietary zinc levels on energy and nitrogen utilization in West African dwarf kids.

Abstract

Zinc is an essential dietary mineral for growth and pregnancy in livestock. However, its requirement for indigenous livestock has not been given adequate attention. Therefore, zinc requirement for energy and nitrogen utilization in West African dwarf (WAD) kid was investigated. Forage crops and commercial rations from four different feed mills, were analyzed to provide baseline zinc levels to which goats were exposed. Twenty-one weaned WAD female kids, aged 5-6 months and weighing 4.8-5.6kg were randomly assigned to seven dietary treatments and were further replicated three times. in a completely randomized design. Animals were transferred to individual metabolic cages for separate collection of feaces and urine 14 and 15 weeks later. Parameters determined were dry matter intake (DMI), energy utilization and nitrogen utilization. The mean±SE of Panicum maximum, Andropogon gayanus, Pennisetum purpureum, Leucaena leucocephala and Gliricidia sepium, contained 31.2±5.0; 29.1± 3.0;34.6± 6.0; 45.0± 5.0 and 47.1± 4.0mg Zn/kg DM respectively. Growing WAD kids fed 134.0 mg/kg DM had significantly (p<0.05) higher DM1 (% of body weight) of 8.2 as compared with kids fed 44.0, 104.0, 164.0, 194.0, 224.0 and 254.0mg Zn/kg DM which recorded 7.7, 7.9, 7.4, 7.3, 7.1 and 4.3 % respectively. This trend was observed for energy utilization (77.40) which was significantly (p<0.05) higher than other dietary treatments which recorded 74.40. 75.20. 70.10, 65.37, 64.10 and 49.42 respectively. Animals on dietary Zn content of 134.0ppm and 164.0ppm recorded the lowest feed conversion ratio of 6.00. Therefore, growing WAD kids required 134mgZn/kg DM for optimal growth and physiological performance.

Keywords: Dietary Zinc, Requirement, West-African Dwarf goat, Performance