Effects of Varying Dietary Levels of Zinc on Performance of Growing 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 growth in West African Dwarf (WAD) kid was investigated. Five forage crops; Panicum maximum, Andropogon gayanus, Pennisetum purpureum, Leucaena leucocephala and Gliricidia Sepium,and commercial rations from four different feed mills, were analyzed to provide baseline zinc levels to which goats are exposed. An isonitrogenous and isocaloric diets, varied by levels of Zn (mg/kgDM). 44.0 (basal), 104.0, 134.0, 164.0, 194.0, 224.0 and 254.0 were formulated. Twenty-one weaned WAD female kids, aged 5-6 months and weighing 4.8-5.6kg were allotted to the treatment diets, using three replicates 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, weight gain, feed conversion ratio nitrogen retention and haematological parameters. 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 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. The same trend was observed with WG (g/day) of 128.3 which was significantly (p<0.05) higher than others which recorded 57.1. 71.4, 78.8, 92.9, 64.3 and 9.0 respectively Nitrogen retention (% ) of 84.06 was significantly (p<0.05) higher than others which recorded 79.88, 81.70, 83.17, 83.07, 83.11 and 65.97 respectively while the kids fed 134.0 and 164.0mg Zn/kg DM recorded significantly (p<0.05) lower FCR of 6.00 as compared with others fed 44.0, 104.0, 194.0, 224.0 and 254.0mg Zn/kg DM, which recorded 11.93,10.00.6.20.10.67 and 13.6 respectively. Haematological parameters significantly (p<0.05) reduced in values as zinc concentration in feed increased. Growing WAD kids required 134mgZn/kg DM for efficient feed utilization and consequent optimal growth.

Keywords: Dietary Zinc, Requirement, West-African dwarf goat, Feed Utilization.