Utilisation of indigenous knowledge to mitigate challenges of gastrointestinal nematodes in goats.
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Date
2021
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Abstract
Gastrointestinal nematodes (GIN) constitute a huge challenge to goat productivity worldwide,
leading to production losses. Anthelmintic drugs have been used to control GIN, but their
effectiveness has been reduced due to their high cost, scarcity in resource-limited farms, and
drug resistance and residue challenges. Therefore, other sustainable control measures that are
cheaper, readily available, and not chemically manufactured, such as indigenous knowledge
(IK), are required. The broad objective of this study was to investigate IK methods and
practices used to control gastrointestinal parasites in goats.
Face-to-face interviews were conducted on IK experts in Jozini Municipality, KwaZulu-Natal,
South Africa. Experts used IK because it is part of their culture, locally available and
guaranteed to work. Indigenous knowledge was sourced from their forefathers through oral
communication and training. Traditional healers had more sources of IK, including visions,
dreams and spirits. Experts identified GIN as the most common parasites in goats. They used
shape, size and colour in the identification of parasites. Indigenous knowledge was used to
identify symptoms caused by GIN infestations. Thirty-three plant species were identified to
control worm burdens in goats.
A cross-sectional survey was used to determine the extent of IK used to control gastrointestinal
parasites in goats. Cissus quadrangularis Linn. was the most widely used plant (67 %),
followed by Albizia anthelminthica Brongn. (47 %), Cissus rotundifolia (Forssk.) Vahl (42 %),
Vachellia xanthophloea (Benth.) P.J.H. Hurter (38 %), Aloe marlothii A. Berger (38 %),
Sclerocarya birrea (A. Rich.) Hochst (36 %), Gomphocarpus physocarpus E. Mey (36 %), Aloe
maculata All. (35 %), Trichilia emetica Vahl (33 %), Aloe ferox Mill. (32 %), Vernonia
neocorymbosa Hilliard (20 %) and Schkuhria pinnata (Lam) Kuntze ex Thell (16 %). The odds
of farmers using IK in the dry environment were 7.9 times more likely than in the wet
environment. The likelihood of males influencing the use of IK was twice compared to females
(P < 0.01). Adults (> 50 years old) were 1.8 times likely to influence the use of IK than youths
(P < 0.05). Farmers residing on-farm were one time likely to use IK (P < 0.05) than those
staying outside the farm. The likelihood of having a herbalist in the area was 3.6 times likely
to influence the use of IK to control GIN in goats.
A structured questionnaire was also used to determine differences in the extent of IK use to
control GIN in goats between wet and dry environments. The likelihood of males using IK in
the dry environment was eight times (P < 0.01) compared to 1.7 times in the wet environment
(P < 0.05). Adults were 1.2 times likely to use IK than youths in the dry environment (P <
0.05), whereas youths used more IK than adults in the wet environment. Unemployed farmers
in the dry environment were 4.3 times likely to use IK than employed farmers (P < 0.01).
Informally educated farmers used IK more than formally educated farmers in both
environments. Farmers who practiced the traditional Zulu culture were 2.1 times more likely
to use IK in the dry environment and 1.1 times in the wet environment than those who practiced
Christianity (P < 0.05). Farmers who received livestock training were 1.74 times more likely
to use IK in a dry environment than the untrained. The presence of herbalists in the dry
environment was 3.6 times likely to influence the use of IK (P < 0.01), compared to the
likelihood of one time in the wet environments (P < 0.05).
Because IK is based on using symptoms to identify goats infested with GIN, relationships
between faecal egg count (FEC) and packed cell volume (PCV), body condition score (BCS),
and FAMACHA score were determined. A total of 120 Nguni goats made up of weaners, does
and bucks were used across all seasons (post-rainy, cool-dry, hot-dry, hot-wet). Higher egg
counts were observed in weaners (7406 ± 401.4) and does (4844 ± 401.4) during the hot-wet
season, while bucks had the highest counts (5561 ± 529.7) in the cool-dry season. Strongyloides
(30 %), Haemonchus contortus (28 %), Trichostrongylus sp. (23 %), Oesophagostomum sp.
(17 %), and Ostertagia (2 %) were identified in goats and had higher percentage counts in the
hot-wet season. There was no effect of sex on BCS, FAMACHA, PCV and FEC. There was an
interaction (P < 0.05) between age and season on FAMACHA score, BCS, PCV and FEC. A
lower BCS and PCV were observed in weaners in the cool-dry season. Weaners had higher
FAMACHA scores and FEC in the cool-dry season. The rate of change in FAMACHA score
was higher in weaners than does and bucks, as FEC increased (P < 0.01). The rate of change
in the FAMACHA score was higher in the post-rainy season as FEC increased (P < 0.01)
compared to other seasons. There was a linear relationship between FEC and FAMACHA
scores.
The anthelmintic activity of aqueous extracts of Cissus quadrangularis Linn., Aloe marlothii
A. Berger, Albizia anthelmintica Brongn., Cissus rotundifolia (Forssk.) Vahl., Sclerocarya
birrea (A. Rich.) Hochst and Vachellia xanthophloea (Benth.) P.J.H. Hurter against GIN was
investigated. Each plant was used in two forms: dry and fresh. Three extraction methods were
employed, i.e., cold water (infusion), boiled water (decoction) and methanol. Extract
concentrations of 8, 16, 24, 32, 40 % v/v were tested in vitro on the mortality of L3 nematodes.
There was a linear relationship between larvae mortality and concentration of the boiled fresh
form of C. rotundifolia (P < 0.01) extract, cold-water extract of the fresh form of A. marlothii
(P < 0.05), cold-water and methanolic extracts of the fresh form of C. quadrangularis (P <
0.01), methanolic extract of the fresh form and cold-water extract of the dry form of V.
xanthophloea (P < 0.05), cold-water and methanolic extracts of the dry form of S. birrea (P <
0.0001). Quadratic relationships were observed between larvae mortality and concentration of
the fresh form of methanolic extract of C. rotundifolia (P < 0.05), fresh form of methanolic
extract of A. anthelmintica (P < 0.01), fresh form of cold and boiled water extracts of V.
xanthophloea (P < 0.0001), the fresh form of methanolic extract and the dry form of boiled A.
marlothii extract (P < 0.001), fresh form of methanolic extract (P < 0.05) and dry form of boiled
S. birrea extract (P < 0.01), and dry form of boiled and methanolic extracts of V. xanthophloea
(P < 0.05) plant. Farmers used different plant forms and extraction methods of C.
quadrangularis, A. marlothii, A. anthelmintica, C. rotundifolia, S. birrea and V. xanthophloea
based on availability and the knowledge they possessed. The effects of most of the plant
extracts were not influenced by concentrations, suggesting that lower concentrations could be
beneficial for plant preservation and toxicity reduction. However, quadratic relationships
observed in other plant extracts suggest that concentrations with high larvae mortality could be
adopted. These relationships need to be considered as an integrated approach to achieve
sustainable nematode control in goats.
Description
Doctoral Degree. University of KwaZulu-Natal, Pietermaritzburg.