Effects of seasonal advancement on the forage availability, quality and acceptability by grazing gudali cattle in the humid zone of Nigeria
Fourteen Sokoto Gudali cattle weighing 82 ± 11 kg were used to investigate the effect of season on the availability, quality and acceptability of forage. The animals were allowed free grazing for six hours daily and every bite of forages was collected to assess their availability and nutritive value. The forages collected were grouped into classes of grasses, legumes and forbs and their chemical composition determined. The results showed that there was a decline in the quality of the forages as the study progressed from September to December, coinciding with the onset of dry season. There were significant (p<0.05) differences in the dry matter (DM), crude protein (CP) and neutral detergent fibre (NDF) contents of all the forages. DM content ranged from 9.6% (Tridax procumbens) to 32.5% (Centrosema pubescens); CP varied between 3.4% (Cyprus haspan) and 21.2% (Aspilia africana); while the NDF values obtained ranged from 27. 3% in Asystasia gangetica to 91.6% in Cynodon nlemfuensis. The acid detergent fibre (ADF) values obtained were significantly different (p<0.05) in all the forages ranging from 20.0% (Asystasia gangetica) to 49.3% (Axonopus compressus) but there were no significant (p>0.05) differences between the ADF values of C. haspan and Kyllinga erecta. Cellulose fractions among the forages differ (P<0.05) with the least value recorded for A. compressus (5.8%) and highest in T. procumbens (48.0%) except in Pennisetum purpureum, Gomphrena celosoides, Euphorbia hyssopifolia, C.haspan and Kyllinga erecta where there was no significance (p>0.05). Hemicellulose fractions of the forages also differ significantly (p<0.05) but for Rottboellia cochinchinesis, Asystasia gangetica, Euphorbia hyssopifolia, Cyprus haspan and Kyllinga erecta which recorded no significant (p>0.05) difference. Except for Gomphrena celosoides, C. haspan and K. erecta, significant (p<0.05) variations were observed in the lignin content of all the forages with values ranging from 2.7% in Gomphrena celosoides, to 33.0% in K. erecta. Most of the forages showed no significant (p>0.05) variations in their Ash contents although there were differences (p<0.05) in the ash content of A. compressus, Panicum maximum, Setaria barbata, Aspilia africana and P. purpureum. At the end of December, the live weight of the animals have increased to 103 ± 12 kg, indicating an overall acceptability of the available forage and adequate utilization by the Gudali cattle.
Keywords: Sokoto Gudali, grasses, forbs, legumes, grazing.