Feed intake, digestibility, nitrogen utilization and ruminal fermentation characteristics of Red Sokoto goats fed concentrate partially replaced with Piliostigma thonningii foliage

Abstract

Fifteen 9-month-old, Red Sokoto male goats (13.6±0.68 kg) fed threshed sorghum top basal diet, were used to study the nutritive value of Piliostigma thonningii (PT) foliage as a replacement for concentrate. There were three diets: supplementary concentrate fed at 5% of BW; 25 and 50% of the concentrate replaced with PT leaves, respectively. Concentrate replacement with PT linearly increased intakes of total DM (P = 0.02), organic matter (OM), total carbohydrate (TC), fibre fractions, cellulose, condensed tannins (CTs) (P < 0.0001), digestible organic matter (DOM) (P = 0.034), energy (P = 0.031), digestibilities of hemicellulose (HC) (P = 0.006) and cellulose (P < 0.0001), digestible OM fermented in the rumen (DOMR), volatile fatty acid (VFA) and microbial protein synthesis (MPS) (P = 0.034), and digestible crude protein (DCP) (P = 0.029). Diets had both linear and quadratic effects on digestibilities of non-fibre carbohydrate (NFC) (P < 0.0001), neutral detergent fibre (NDF) (L:P = 0.01; Q:P = 0.012), acid detergent fibre (ADF) (L:P = 0.026; Q:P = 0.007) and lignin (L:P = 0.008; Q:P < 0.0001). N retention had a quadratic trend (Q:P = 0.037). Lower intakes of total DM (P = 0.016), OM (P = 0.021), TC (P = 0.009), fibre fractions, cellulose and CTs (P = 0.0001), digestibilities of NFC (P = 0.003), NDF (P = 0.002), ADF (P = 0.004), lignin (P = 0.001), HC (P = 0.006), cellulose (P = 0.011) and energy (P = 0.018), DOM intake, DOMR and MPS (P = 0.002), VFA (P = 0.025) and pH (P = 0.001) were observed in control vs. PT. However, NFC digestibility and urinary N (P = 0.003), and DCP (P = 0.043) were higher for control vs. PT. Supplemental concentrate can be replaced with PT foliage without detrimental effects on feed intake, digestibility, N utilization and ruminal fermentation.