Digestion and utilization of citrus by-products by two breeds of West African goats

Résumé

TWELVE young goats, consisting of 6 West African Dwarf (Fouta Djallon), (10.19 to 15.45 kg).and 6 Red Sokoto (Maradi), (9.09 to 14.09 kg), were used throughout the experiment (3 trials). The 12 goats were maintained on basal forage (Cynodon nlemfuensis) in Trial 1 but in Trial 2, they were divided into two groups with two animals per sub-group. Animals in a sub-group were maintained on basal forage plus 25, 50 or 75 % fresh citrus pulp. In Trial 3, six West African Dwarfs were maintained on similar levels as in Trial 2 but using dried citrus pulp. The results showed that protein content of citrus pulp was low (6%) with high crude fibre value of 15% high moisture content (84%), and high nitrogen-free extractive (NFE) value (57%). Dry matter (DM) intakes of basal forage ration were higher than those of mixtures of basal forage and fresh citrus pulp (P < 0.01) due probably to high moisture content of the pulp, because the DM intakes of dried pulp mixtures were higher than those of basal rations (P < 0.01). The rations with 50% fresh or dried pulp was consumed more than the other mixture. Fresh pulp significantly depressed nutrient digestibilities at all levels of supplementation relative to basal forage (P < 0.05), while those of dried samples were about the same with the values for the basal ration. Red Sokoto and West African dwarf goats retained 39.29 and 41.34g/N/100g/N consumed respectively when fed on forage only, but 11.43 and 17.03, 14 11 and -14.22, -2.48 and 15.23g N/100g N consumed respectively when fed on grass/fresh citrus mixtures. The corresponding N retention for West African dwarf goats were 38.51, 31.86 and 40.01g N/100g N when fed the forage dried citrus mixtures. The digestible energy (DE) and metabolizable energy (ME) intakes for these animals were optimal at the 25 and 50% citrus supplementation. There was highly significant correlation between ME intake and liveweight changes throughout the experiment (P <0.01]). Animals fed on forage fresh pulp mixtures lost weights (-0.59 <0.01 kg/ animal/week) in Trial 2, while those on forage-dried citrus mixtures gained weights (0.05 <03 kg/ animal/week) in Trial 3.