Goats play an important role in the socio-economic activities of people, especially in developing countries, by providing food and income (Peacock 2005). However, parasites limit goat productivity as they reduce fertility, cause skin irritation and suck blood, ultimately leading to death (Molefe et al. 2012). Gastrointestinal parasites such as Haemonchus contortus and Fasciola hepatica are a major health problem in small ruminants (Vatta & Lindberg 2006). External parasites such as ticks, lice and mites have also been reported in goats. Most of these parasites are more prevalent in developing countries because of inappropriate housing and lack of adequate veterinary services (Mungube et al. 2006). Commercial drugs are mostly used to control parasites; however, these are expensive and are out of reach for many resource-poor farmers. Some of the parasites have also developed resistance against these drugs (Clark, Stephen & Cawley 1996), and the drugs can pollute the environment (Wall 2007). This has led farmers to resort to alternative measures that include the use of medicinal plants to treat and control livestock parasites. There is also a belief that natural products are safe to use and harmonious with the biological system (Erasto 2003). Knowledge on the use of ethno-veterinary medicine is passed on orally, and there is a danger that this information might disappear because of technical and socio-economic changes. Therefore, this study was conducted to document the medicinal plants used to control internal and external parasites in goats in the Chris Hani District Municipality, South Africa. This will help in the pharmacological study of these plants and in the development of therapeutic drugs that have fewer side effects than synthetic chemicals.

In this study the demographic characteristics of the farmers were similar to those reported by Mwale and Masika (2009) in the Eastern Cape and Limpopo Provinces of South Africa (Luseba & Van der Merwe 2006). The majority of the households were male headed, whilst the most dominant age group consisted of older generations. Most of the respondents who were using medicinal plants and had essential knowledge were generally older than 51 years. The findings of this study agree with those of Wanzala et al. (2005), who mentioned that information on medicinal plants is mostly stored in the memory of a few older people entrusted with it within communities. Most of these older people are unemployed and rely on grants for their survival. This concurs with findings by Masika, Van Averbeke and Sonandi (2000) who reported that most of the farmers rely on grants. The reason could be that most of them are old and poor, so grants are their major source of income.

The reasons for keeping goats were similar to those cited by Bester, Ramsay and Scholtz (2009) and Masika and Mafu (2004). Most of the farmers were keeping goats for cultural reasons and for cash income. The use of goats for milk was unpopular as reported previously by Mahajana and Cronje, (2000) and Masika and Mafu (2004). Furthermore, most of the farmers mentioned parasites as the most problematic challenge that they were facing and this concurs with studies by Mwale and Masika (2009). Parasites might be a problem in this area because the animals are raised on poorly managed pastures where parasites are abundant. Infestation with internal and external parasites was reported to be more prevalent in the summer season, which could be because of poor management of pastures (Masika & Mafu 2004), inappropriate housing (Mungube et al. 2006) and climatic conditions in the tropics (Webb & Mamabolo 2004; Phiri et al. 2007), which are favourable for parasite development.

Findings from this study revealed that farmers usually dipped their goats to control parasites. However, this contradicts the findings by Kunene and Fossey (2010), who observed that most goats are hardly dipped in rural communities. The farmers questioned in this study are not provided with commercial drugs to control internal parasites. The majority of the respondents (69.23%) used medicinal plants, whilst others bought their own commercial drugs (11.54%) and a proportion (19.23%) used both medicinal plants and commercial drugs to control parasites in their herd. Farmers gave reasons why medicinal plants are still in use, which included the efficacy of the plants, no side effects, and cheap and easy accessibility. Moreki, Dikeme and Poroga (2010) attributed the wide use of ethno-veterinary medicine in villages to lack of knowledge about the use of commercial drugs and their high price in most areas. However, Gueye (1999) argued that the use of ethno-veterinary medicine is the only option for most resource-limited farmers in Africa because of lack of veterinarians in the rural areas. Farmers reported that they were able to define diseases using clinical signs, but it should be kept in mind that some diseases exhibit similar signs (differential diagnosis) and that may affect the accuracy of the diagnosis. Wrong diagnosis of disease will result in incorrect dosage, and this can affect the efficacy of the herbal remedy.

The most frequently mentioned plant family was Asphodelaceae. Maphosa and Masika (2010) reported similar findings. This could be as a result of its vast natural distribution, with 13 genera (Treutlein et al. 2003). Aloe ferox and Bulbine latifolia were the plant species reported that belong to the family Asphodelaceae. In this study, leaves were the most used plant parts mentioned, which concurs with previous studies (Gebrezgabiher et al. 2013; Maphosa & Masika 2010; Masika & Afolayan 2003; Mohammed & Seyoum 2013; Setlalekgomo & Setlalekgomo 2013), who reported the highest percentage use of leaves for ethno-veterinary purposes. The use of leaves in preparation of herbal remedies reduces loss of plants from the natural habitats as it does not destroy the whole plant. On the other hand, this study contradicts findings by Cheikhyoussef et al. (2011), who reported that roots were the most commonly used plant part. The use of roots in preparation of herbal remedies is not advised, as this results in loss of medicinal plants from their habitats. Decoction was the most commonly used preparation method in this study. This is in agreement with Maphosa and Masika (2010) and Djoueche, Azebaze and Dongmo (2011), who reported decoction as the most used method for preparing medicine. Decoction involves boiling part of the plant in water for a few minutes. This process extracts water-soluble polar compounds and the high temperature is responsible for reducing the toxicity of thermolabile compounds that may be poisonous to the animals (Djoueche et al. 2011). However, some thermolabile compounds may also be lost in the process, which can affect the efficacy of the plant.

Some of the respondents combined more than one plant in preparation of medicines. The use of combined plant materials was also reported by Masika et al. (2000) and Maphosa and Masika (2010) but contradicts findings by Van der Merwe, Swan and Botha (2001), who reported use of a single plant. Other respondents mixed plant materials with nonplant substances such as Epsom salts, rock salt, butter, oil cake, flour and potassium permanganate. These findings were similar to previous reports of mixing with nonplant materials (Djoueche et al. 2011; Maphosa & Masika 2010; Mohammed & Berhanu 2011; Mohammed & Seyoum 2013). Mixing of plant materials with nonplant substances influences the absorption of compounds contained in the plants (Djoueche et al. 2011). Epsom salts are known to have a laxative effect. Oil cakes increase bile secretion, which promotes the solubilisation of non–water-soluble compounds (Djoueche et al. 2011). Rock salt has emulsifying properties assisting formation of stable emulsions in the gastrointestinal tract and therefore increasing the solubilisation of alkaline compounds in plant extracts, thus increasing their absorption (Djoueche et al. 2011). Addition of butter is known to improve the flavour and reduce the chances of animals vomiting (Mohammed & Seyoum 2013).

Farmers in the Eastern Cape Province are aware of the toxicity of some plants such as A. oppositifolia and therefore add more water to the herbal preparations and boil the plant material before administering it to the animals. They also mixed A. oppositifolia with other plant materials such as A. ferox. Akocanthera oppositifolia is toxic because of the cardiac glycosides it contains. This is in consonance with studies by Maphosa and Masika (2010), who reported the awareness of poisonous plants by farmers in the Eastern Cape Province. Adding large quantities of water before boiling results in the extract becoming more dilute and therefore the toxicity of the plant will be reduced. Boiling the plant extract also reduces toxicity by evaporating aromatic poisonous compounds.

Some of the plants that were being used by farmers to control parasites in this study area have been reported to possess pharmacologically active substances. Of the nine plants species used to control parasites in goats in Chris Hani District, A. ferox was the most frequently used plant as previously reported (Maphosa & Masika 2010; Moyo & Masika 2009; Setlalekgomo & Setlalekgomo 2013). The plant A. ferox has a laxative effect because of the presence of glycoside aloin (Steenkamp & Stewart 2007; Eloff & McGaw 2014). It is also known as an insect repellent; is used to treat heartwater and gallsickness (Van Wyk, Van Oudtshoorn & Gericke 2002), poultry diseases, sheep scab, and to control ticks in cattle (Moyo & Masika 2009). Elephantorrhiza elephantina is used to treat heartwater (Eloff & McGaw 2014; Luseba & Van der Merwe 2006; Van der Merwe et al. 2001) and used in goats to control helminths (Maphosa & Masika 2010; Okoli, Tamboura & Hounranghe-Adote 2010) and in humans for high blood pressure (Mathias-Mundy & McCorkle 1989). Elephantorrhiza elephantina possesses antibiotic properties (Van Wyk & Wink 2004; Van Wyk et al. 2002). It relieves inflammation in animals and is also used as a purgative (Cocks 2006). Centella coriacea contains triterpenoids that have antibiotic and purgative effects. Agapanthus praecox has been reported to contain saponins that have antibiotic, analgesic, laxative, anti-oedema, anti-inflammatory and immunoregulatory effects (Van Wyk et al. 2002). Albuca setosa is used in the management of diabetes mellitus (Oyedemi et al. 2011). Acokanthera oppositifolia has been reported to treat anthrax and tapeworms (Dold & Cocks 2001). FL values of A. ferox, A. oppositifolia, A. setosa and E. elephantina were high, showing that most people in the area prefer these plants and constantly use them in controlling parasites. In this study, the most cited plants had the highest FL, contrary to findings by Njoroge (2012). Trotter and Logan (1986) reported that plants that are constantly used by people in a certain area are more likely to contain bioactive substances. Validation of these plants is important so as to isolate the active compounds and produce drugs from these plants.

Some plant species had low FL values because some of the respondents did not know the preparation methods and dosages. Most of the informants acquired their knowledge from their elders, as reported by Mwale et al. (2005) and Mwale and Masika (2009). Ethno-veterinary knowledge is not written and is accepted orally from elders, analogous with earlier studies (Farooq et al. 2008; Giday, Asfaw & Woldu 2009). It is important to document ethno-veterinary knowledge so that it will not be lost and to increase the use of common plants. The bulk of plant matter is collected from the natural vegetation, which poses a major threat to its existence. Farmers should use plant parts such as leaves rather than the whole plant to prevent plants from becoming extinct (Maroyi 2012). Other respondents cultivate the plants in their gardens, and this is not recommended as it is believed that monoculture conditions do not trigger the production of secondary metabolites (Schippmann, Leaman & Cunningham 2003). Plants that are cultivated are believed not to possess power compared with wild plants. Therefore, it is advisable to use wild plants that grow under stress conditions and competition, as they possess secondary metabolites.