NUTRITIVE VALUE OF PROCESSED GROUNDNUT (Arachis hypogaea L.) HAULM-BASED DIETS FOR WEST AFRICAN DWARF RAMS

Abstract

Groundnut Haulm (GH) is a crop residue often used as a supplement for ruminant feeding in Nigeria especially during dry season. The use of GH as feedstuff is limited by bulkiness and high fibre content. Pelleting and urea-treatment have been widely used to improve the nutritive quality of high fibrous and bulky feedstuffs for ruminants. However, information on urea-treated GH and pelleted GH-based diets for ram in Nigeria is scanty. Therefore, nutritive value of urea-treated and pelleted GH-based diets for West African dwarf rams was evaluated.

Urea-Treated Groundnut Haulm-UTGH (100 kg GH + 4 kg urea/100L water) or Untreated GH (UGH) was mixed with concentrate at ratio 40:60 to formulate total mixed ration with or without pelleting. The four dietary treatments: UGH-Unpelleted (D1), UTGH-Unpelleted (D2), UGH-Pelleted (D3) and UTGH-Pelleted (D4) were assayed for Crude Protein-CP, Neutral Detergent Fibre-NDF and Acid Detergent Fibre-ADF using standard procedures. Total Gas Volume-TGV (mL), Methane (mL/200 mg DM) and Metabolisable Energy-ME (MJ/kg DM) were determined using in vitro gas production technique. Sixteen rams were allotted to the diets in a completely randomised design for 105 days to determine Dry Matter Intake-DMI (g/day), Daily Weight Gain-DWG (g/day), Feed Conversion Ratio-FCR, NH3-N (mg/100mL) and rumen Total Volatile Fatty Acid-TVFA (mmol/100mL) using standard procedures. In a seven-day metabolic study, Nitrogen Retention-NR, Crude Protein Digestibility-CPD and Crude Fibre Digestibility-CFD were determined using standard procedures. Data were analysed using descriptive statistics and ANOVA at α0.05.

The CP of 9.5±0.7% for D3 was lower than 11.9±0.2%, 11.4±1.0% and 11.3±0.6% in D1, D2 and D4, respectively. The NDF ranged from 54.5±1.1% (D1) to 56.9±1.3% (D2), while ADF of 39.9±1.0% (D1) was lower than 42.6±2.5% (D2), 42.3±1.6% (D3) and 41.5±1.4 (D4). The TGV of 27.1±0.1 for D2 was higher than 19.2±0.8, 16.2±1.2 and 12.4±1.2 for D3, D4 and D1, respectively. Methane and ME ranged from 6.0±0.02 (D1) to 15.0±1.20 (D2); and 4.9±0.3 (D2) to 5.6±0.4 (D4), respectively. The DMI of 578.9±20.2, 512.3±16.5, 474.0±17.2 and 450.0±12.5 for D3, D4, D1 and D2, respectively, were not significantly different. The highest DWG of 49.1±4.6 was recorded for rams on D4 and lowest of 18.7±8.5 for those on D1 indicating that urea-treatment and pelleting of diet enhanced growth performance in rams. The FCR ranged between 10.7±1.1 in D4 and 13.8±2.6 in D2. The NH3-N of 29.7±0.01 (D4), 28.7±0.01 (D3), 25.5±0.02 (D2) and 24.4±0.04 (D1) were similar. The highest TVFA of 258.4±20.1 was observed in rams allotted D3 and lowest of 244.9±8.8 in rams fed D1 showing that pelleting improved energy value of the diet. The NR of 80.7±6.4% (D2) and 79.8±4.4% (D1) were similar and significantly higher than 74.6±4.0% (D4) and 73.4±2.3% (D3). The CPD values of 83.4±0.02%, 83.1±0.01%, 78.1±0.03% and 77.9±0.10% in rams on D2, D1, D3 and D4, respectively, were not significantly different. The CFD ranged from 64.4±0.02% in D4 to 68.2±0.10% in D2.

Pelleting improved the nutritive value of groundnut haulm-based diets for West African dwarf rams. The growth performance of rams fed processed groundnut haulm-based diets was enhanced.