Quantification and characterisation of nutrients in Senegalia Mellifera milled biomas, feed intake and nitrogen balance in female boer goats fed with Senegalia Melifera bush-based feeds
Loading...
Date
2019
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Namibia
Abstract
The objectives of this study were to quantify and characterize the nutritional content of milled Senegalia mellifera milled biomass obtained from nine blocks at Neudamm farm and to determine the dry matter intake (DMI), apparent digestibility and nitrogen retention in female Boer goats fed with Senegalia mellifera bush based feeds. Wood ash (WA), Polyethylene glycol (PEG, 6 000) and Biochar were evaluated as tannin deactivation methods. The milled biomass of S. mellifera was mixed using a clean concrete mixer with the following ingredients: yellow maize meal, liquid molasses; Marula oil press cake and coarse salt to formulate a complete diet with 14%CP and 11MJ ME/kg. Detannification treatments methods were added at a level of 5 g per day during feeding time. Eight (8) female Boer goats, with an average initial body mass of 31.5 kg (± 2.5 kg), were used in the feeding experiment. The goats were penned individually in metabolic cages measuring 120 cm long, 54 cm wide and 90 cm above the ground, allowing for the total collection of faeces and urine separately. Clean water was available ad libitum to the goats during the entire feeding experiment. The goats were fed in a 4x4 cross over Latin square design with four periods of experimental feeding. Each period lasted for 17 days, resulting in 68 days of experimental feeding. The goats were fed twice daily at 09:00h and 16:00h. The level of dry matter (DM) of feed offered was 4% of body weight. The results obtained in this study showed that there was a significant difference (p <0.05) in the chemical composition of Senegalia mellifera milled biomass harvested from the nine blocks at Neudamm farm. The CP content of Senegalia mellifera milled biomass ranged from 9.39 to 9.68 %DM while the NDF and ADF ranged from 59.17 to 64.33%DM and 43.77 to 48.01%DM, respectively. The condensed tannins (CT) content from all blocks did not differ (p >0.05) and had a mean of 0.02 to 0.03%DM as leucocyanidin equivalent (LE Absorbance at 550 nm).
The results obtained from the feeding trial showed that there was significant difference (p <0.05) in the organic matter (OM) and ash content of different treatment diets. The apparent digestibility coefficient of DM, OM and NDF were not significantly different among treatments and the control diet (p >0.05). Goats fed Biochar treated diet had the highest nitrogen intake (13.74g/d (p <0.05), faecal nitrogen of 8.43g/d (p <0.05) and nitrogen retention of 5.11g/d (p <0.05), while goats fed the control feed (CNT), PEG and WA were similar (p >0.05). All treatments resulted in a positive nitrogen retention (p >0.05) with mean values ranging from 3.79 to 5.11 g/d. The study concluded that, there was a significant difference (p <0.05) in the chemical composition of S. mellifera milled biomass collected from nine blocks at Neudamm farm. Given the high CP content of the S. mellifera, this fodder resource can be considered a suitable supplement for poor quality (low N content) natural pastures and crop residues such as grass hay, straw and stover. The study also concluded that, there was a significant difference (p <0.05) in the DMI, and nitrogen balance in Boer goats fed with S. mellifera feeds treated with Wood ash (WA), Polyethylene glycol (PEG, 6 000) and Biochar (BIO). The study therefore recommends that each detannification method should be tested at different rates of inclusion in S. mellifera bush based feed resources.
Description
A mini thesis submitted in partial fulfilment of the requirements for the Degree of Master of Science in Rangeland and Resources and Management
Keywords
Wood ash, Biochar, Nitrogen