Performance of Nguni goats supplemented with sweet potato vines
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Date
2018
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University of Zululand
Abstract
Goats are small ruminants that play a major role in food security, especially as their meat and milk serve as vital sources of protein in most rural houses in developing countries. Goats in developing countries mostly depend on veld as feed that often does not provide the nutrient requirements necessary for optimum production. Supplementary feeds available are often expensive especially for emerging farmers but crop residues like banana leaves, cassava, sweet potato vines and other indigenous crop residues not exploited may be used as a cheaper source of feed supplement. More rural emerging farmers in Northern KZN communities seem to be farming sweet potatoes which implies that the vines could be available cheaper for supplementary feeding if found with feed potential. Thus, the aims of this study were to survey the knowledge and perception of indigenous forage supplementation especially sweet potato vines, the effect of vine cutting frequency on the chemical composition and in vitro digestibility as well as sweet potato yields of different sweet potato cultivars and the final aim looked at the effect of vine supplementation on goat’s intake and performance as well as its anthelminthic potential, if any.
The survey was conducted in 7 wards of KwaMthethwa community area under Umfolozi local Municipality, where 15 farmers were interviewed per ward using a questionnaire. The effect of vine cutting frequency (after 60, 75 and 125 days) on the vine chemical composition (crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF), acid detergent ADL, condensed tannin (CT)) and in vitro digestibility (apparent digestibility (APD), true digestibility (TD), microbial yield (MY)) as well as sweet potato yields of the different cultivars (Beauregard (BRGT), 1990, A40 and A45) were done at Owen Sithole College of Agriculture (OSCA) farm and University of Zululand Agriculture laboratory. Goats (32) of similar average weight, were categorised into four groups of eight and placed in individual pens. They were given hay ad libitum and supplemented with four different rations (0kg, 1.5kg, 2kg and 3kg) of sweet potato vines (SPV) from 1990 as best cultivar. The effect of 1990 supplementation on goats’ hay intake (total feed intake (TFI) and in vitro digestibility (DMD) and performance (weight gain (WG), average daily weight gain (AVD) and feed conversion ratio (FCR)) were measured. Anaemic condition of goats was monitored as well as egg counts for haemonchus contortus infestation. The survey results showed that farmers seem to have an idea of supplementing, however majority fed maize in the afternoons, for goats to be able to come back for kraaling without a header. Most farmers agreed that goats were losing condition due to diseases and malnutrition, but rural farmers rejected the use of sweet
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potato vines as feed supplement even when it was available because they believed it causes fatal diarrhoea.
It was found that nutrient status of vines was reduced (P<0.05) as the plant matures, and fibre (NDF and ADF) increased as vine matured. The CP concentration was decreased (p<0.05) and CT increased (p<0.05) as the plant matured, with an exception of A45 cultivar that had lower tannin concentration even at 120 day after planting (DAP). Furthermore, harvesting vines at 75 DAP improved (P<0.05) the yields of sweet potato tubers and vines. The Cultivar 1990 was considered the best because it produced the highest yields of forage materials as well as tubers hence not compromising its original purpose of production for human consumption. It was observed that goats given 3kg SPV (T4) had the highest (p<0.05) final weight (FW), total weight gain (TWG) and average daily gain of 26.05kg, 4.18kg and 74.56g/day, respectively. Moreover, the feed intake increased (P<0.05) with increasing feed levels of sweet potato vines. Most interestingly, the egg per gram (EPG) was reduced in all groups of goats fed sweet potato vines but not for the control group. The results from these studies showed that sweet potato vines have a feed potential as well as anthelminthic potential and rural farmers can be advised to apply it at T4 levels after 75 days of harvest and no diarrhoea signs were observed.
Description
Dissertation submitted in fulfilment of the requirements for the Degree of Master of Science in Agriculture (Animal Science) Department of Agriculture Faculty of Science and Agriculture at the University of Zululand, 2018.
Keywords
Food security, Sources of protein, Farmers