Effect of ensiling Acacia nilotica and Vachellia karroo pods and leaves with molasses and urea on the chemical composition, secondary compounds and in vitro degradability of silage
Loading...
Date
2020
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Fort Hare
Abstract
The study aims to evaluate chemical composition, in vitro degradability, secondary compounds, and pH of Acacia nilotica and Vachellia karroo (pods and leaves). Two trees per browse species were selected, for harvesting leaves and pods. A completely randomized design was used where each treatment was replicated three times. Then 50% of grass and 50% of pods and leaves were mixed with 3% molasses and urea. The Acacia nilotica and Vachellia karroo (pods and leaves) were harvested just before winter (March-April 2018) at Honey Dale Farm. Kikuyu (Pennisetum clandestinum) was also harvested at the Research Farm of the University of Fort Hare. The fresh Kikuyu grass was cut into small pieces together with Acacia nilotica and Vachellia karroo (pods and leaves). The samples were packed and compacted by hand, pressing into one (1) litre consol jars with airtight fitting lids. The jars were kept at room temperature for 42 days. The silage was analyzed for chemical composition (CP, NDF, ADF, DM, ADL, ash, OM and pH), secondary compounds (condensed tannins and phenolics) and in vitro degradability.
Phenolics showed significant differences (P< 0.05) in urea and molasses treatments. On browse trees Acacia nilotica leaves with urea (0.34), Acacia karroo pods leaves with molasses (0.42) and Acacia Karroo pods with molasses (0.45) had low levels of phenolic compounds compared to Acacia nilotica pods with molasses (0.55).
Treatments showed significant differences (P<0.05) in tannin content Acacia karroo leaves with urea (0.22), Acacia nilotica pods with urea (0.23) and leaves with molasses (0.23) and Acacia karroo leaves with molasses (0.28) had low levels compared to Acacia nilotica leaves with urea (0.39). In addition, pH showed significant differences (P<0.05) between all the treatments. Acacia nilotica pods with urea (4.91), Acacia nilotica leaves with molasses (5.23), Acacia nilotica leaves with urea (5.27), and Acacia karroo leaves with molasses (5.40) had low levels compared to Acacia nilotica pods with molasses (6.66).
The browse silage results showed significant differences (P< 0.05) among all the treatments in their dry matter content. Acacia karroo leaves mixed with molasses, and Acacia nilotica leaves mixed with urea had higher (P<0.05) dry matter content than others. There were highly significant differences (P<0.05) between neutral detergent fibre (NDF), ash acid detergent lignin (ADL), crude protein (CP), organic matter (OM), and acid detergent fibre (ADF) was also significantly different (P<0.05). Acacia karroo pods ensiled with urea (11.90%), Acacia karroo leaves with urea (9.89%), and Acacia nilotica pods with urea (9.21%) had higher CP content than other treatments. The digestibility of treatments compared to time were significantly different (P<0.05) and within the columns, although there was no significant difference (P>0.05) in the 12th and 36th hours. Acacia karroo leaves mixed with molasses had
the highest (488.23) on the 0 hour and Acacia Nilotica pods with urea on the 12th hour (144.10). In conclusion, ensiling using urea and molasses had a positive effect on secondary compounds, chemical composition and digestibility.
Description
Masters dissertation
Keywords
Acacia nilotica, Biochemistry, Phenols, Silage, Urea, Molasses
Citation
Twalo, N.M. (2020) Effect of ensiling Acacia nilotica and Vachellia karroo pods and leaves with molasses and urea on the chemical composition, secondary compounds and in vitro degradability of silage. MSc Agriculture (Animal Science) thesis. Alice, South Africa: University of Fort Hare.