Medicinal plants used in ethnoveterinary practices in Dawuro zone
The importance of livestock in mixed farming systems is indicated by the numerous indirect effects of animal diseases in the study area and at country whole. Animal diseases are a major constraint to income generation and asset acquisition by the poor, since poor people have limited cash to pay for disease treatments [2-4,36]. To manage this problem livestock keepers, particularly in rural areas frequently uses traditional remedies to get solutions for their ill-health animals. Ethnoveterinary remedies are mainly made from plants, but also from animal body parts and by-products, kerosene, oil, common salt, and soaps [8,37-41].
Indigenous people in Dawuro zone are dependent on livestock is for supporting their livelihood. Medicinal plants have a vital role in the treatment of livestock’s health problems in the area. Identification of specific livestock ailment types in the area was found to be made based on indigenous knowledge of symptoms and corresponding livestock illnesses held in the memories of local people. Similar was found true in selecting medicinal plants which were thought to be most appropriate to manage different veterinary health problems [19,42].
The rich knowledge of ethnoveterinary medicinal plants in Dawuro zone that was indicated by the number and diversity of plants reported. The results showed that there was no significant difference in the average number of plants reported either by female or male respondents indicated that both men and women members of the community have good ethnoveterinary knowledge. However, discordant to this finding, men had more knowledge of plant usage because they are naturally selected during childhood to be apprentices of ethnoveterinary practices [19,43,44,45]. In this study, the knowledge regarding the treatment of animal ailments did not show any difference between the age groups. In other studies, however, it was observed that the number of medicinal plants reported was increased with age, and the older informants reported more medicinal plants than younger individuals [46-49]. This could be related to a higher degree of cultural contact and experience of the elderly members with curative plants than that of younger members in the community. Comparison of medicinal plant knowledge held among community members of varying education level showed significant difference (P<0.05) in plant use by illiterate informants reported significantly more medicinal plants over literate ones. This was also observed in other ethnoveterinary survey [44,49,50].
In the present study, 90.4% of traditional healers responded that they acquired their knowledge from their parents or close relatives. Moreover, the traditional healers have a very high intention to keep their ethnoveterinary knowledge secrete and unwillingness to transfer their knowledge freely to new generations. In line with the present study, other studies have reported that the highest medicinal plant knowledge acquisition by the healers was from parents or close relatives and they have a very high intention to keep their traditional knowledge secret elsewhere in Ethiopia [14,49,51-54], and other countries [1,34,41,42] share a similar concern on the knowledge gap down generations in different cultural groups. On the other hand, deforestation (reported by 89% of informants) for agricultural expansion, charcoal production, firewood collection; and overgrazing (29%) were claimed as major factors affecting medicinal plant resources among the Dawuro society. Similarly, [19] reported that deforestation was principal threat to medicinal plants in Ankober area.
A total of 103 plant specimens having medicinal value were botanically classified and distributed into 34 families. In this study, the best representation of plant species having ethnoveterinary medicinal value was found in Asteraceae with 13 species has the highest species followed by Fabaceae (11 species), Lamiaceae (9 species) and Euphorbiaceae (7 species), respectively in the area. In line with this study, Asteraceae, Fabaceae, Lamiaceae and Euphorbiaceae, have also been reported as dominant families in other studies [55,56]. Moreover, herbs were the most commonly used plant habit in the study area. However, discordant to this finding, shrubs have been used as the most important ethnoveterinary medicinal plants in the other part of the country [57,58-61].
The degree of ethnobotanical richness of the Dawuro zone based on the number of plant species and medicinal uses per informant is higher compared with the studies conducted in Ethiopia [2,10,14,40,62], in Brazil [50], South Africa [63,64], Pakistan [34,65], and India [56,58]. This could reflect a cultural conservation in the ethnobotanical and medical knowledge in the area, as suggested by the relatively high number of species reported by single informants. The millennia-old interaction of indigenous people in the area within the vicinity available medicinal plants might have enabled them to develop an indigenous knowledge system best fit to select and use diverse curative medicinal plants to treat frequently occurring livestock diseases. The study of [19] pointed out that knowledge on plant use is the result of many years of human interaction and selection of the most desirable and successful plants present in the immediate environment at a given time.
Traditional medicinal plants used by the people in Dawuro zone are also used in other parts of the country and other African countries as reports indicate. This has been proved by botanical identifications of the plant species and comparison with the reports of other scholars elsewhere. The studies commonly reported, examples Croton macrostachyus and Ricinus communis L. recorded for the Gilgel Ghibe area and Borana pastoralists [2,52]; Syzygium guineense, Buddleja polystachya and Amaranthus caudatus L., reported for peoples of Ejaji area (Chelya Woreda) [60]; Indigofera oblongifolia Forsk and Solanum incanum L. used in Afar region [49]; Vernonia amygdalina Del., and Juniperus procera L. reported for Ankober district of Amhara region [19]; while Withania somnifera L., Azadirachta indica L. and Allium sativum L. recorded for Hills of Eastern Ghats, India [61]; Ximenia americana L., and Withania saminfera L. recorded for the South Africa [64]; and Erythrina abyssinica and Jatropha curcas reported for Western Uganda [66]. The similarity could be common share of their cultural and traditional practices, and the distribution/availability of the species in use in the areas explored for their ethnoveterinary knowledge.
However, certain new plant species were used by Dawuro people compared to other studies conducted in Ethiopia, which are used as a treatment for different livestock diseases [2, 10,14,19,62,67,68,69]. Clausena anisate, Clutia abyssinica, Solanecio mannii, Dracaena steudneri, Cyphostema sp.,Arisaema enneaphyllum, Haplocarpa sp., Cynoglossum coeruleum, Colocasia esculenta L., Lycopersicon esculentum mill, and Oxytenanthera abyssinica were newly identified and reported plants used to treat the most prevalent animal health problems reported in the study area. The reason could be related to the age-old ethnoveterinary experiences of traditional healers and dominant vegetation of these species in the area.
The leaves were found to be the most harvested plant parts, followed by roots in remedies preparations. Our finding consistent with previous reports in Ethiopia and elsewhere [50,60,70-73]. This could be explained by traditional beliefs of the community about leaves having no difficulty in collection, preparation, and the main site of photosynthesis that could be a possible reason for their effectiveness and efficacy against animal health problems. However, in contrast to this study [19,73,74] have found that the root is as the most used part in their studies. The difference could be as the pharmaceutical value and concentration of active ingredients in each plant variety depending on climatic and edaphic factors. People inhabiting different ecological zones use different plants and plant parts in their treatment arsenal stated by [2,54]. The dominant practice of harvesting majority (56.2%) of ethnoveterinary plants of Dawuro zone is from wild sources. This would indicate the degree of anthropogenic pressure exerted on wild plant resources of the area. Overdependence on wild resources together with reduction of the wild resources due to ever-increasing population pressure poses a threat to medicinal plant riches of the area. Comparable trends in overharvesting medicinal plants from uncultivated sources were also reported in other parts of Ethiopia [19,43,51,52,69,76], in Pakistan [65,77], and Brazil [50].
About 93.4% ethnoveterinary medications were reported to comprise remedial parts of a single medicinal plant in the present study, which is in agreement with the findings of studies conducted elsewhere in Ethiopia [78,79]. However, 6.6% of the traditional medications were also prepared using formulations from two or more ethnoveterinary medicinal plant species either similar or different parts of the plants for treating livestock ailments may be attributed to the expected synergistic effect of combinations of parts and their bioactive ingredients to treat ailments. The therapeutic efficacy of combinations of medicinal plant parts used by other people living in northwest Ethiopia for treating various ailments has also reported by [33,79].
In this study, some medicinal plants were used to treat more than two ailments, while others are used to manage one ailment. The highest number of multiple ethnoveterinary uses were recorded for Capsicum frutescens (treated against 12 ailment types) and Lepidium sativum (10 ailment types); however, in contrast to this study, [19,51] have found that Allium sativum and C. guianensis were highest number of multiple ethnoveterinary uses, respectively.
Pounding the remedial part in wooden or stone-made mortar and pestle; and homogenizing it with cold water was found to be the most common method of local drugs extraction (78.8%), which is in line as documented in other studies [19,60,80] who reported pounding the remedial part and homogenizing it with water was found to be the major mode of remedy preparation. However, it is generally believed that the potency of the treatments can be enhanced when used in concoction form described by [34]. Oral (72.35%) administration is reported to be the best-represented route of administration as in the finding of [81,82] who reported oral as the most commonly used administration routes of medicine used in Eastern and Western Ethiopia. It is also in agreement with the result of various ethnobotanical studies conducted elsewhere in Ethiopia [19,80,83] which indicates oral as the predominant route of administration used by the herbalists. Besides, the majority of herbalists were administered the preparations for three consecutive days or keep treating until the animal recovers if the disease is not acute case.
Most of the recipe was prepared using a single plant in different formulations and administered in different routes depending upon the type of the disease needed to be treated as reported by (78,79,81]. Even though healers used various units of measurements to estimate doses of local medicines such as numbers (e.g., for seeds, fruits,), and cups and glass (e.g., for water during preparation and liquid form of the prepared medicine), plastic jugs, bottles, syringe and guard local called ”Buliyaa“, no strictly standardized doses of herbal preparations as known for modern veterinary medicine were reported by traditional healers for any of the preparations used to treat livestock ailments in the present study areas. The same findings were also reported from other studies conducted in different parts of the world [34,50,65,72,84] who found that the lack of precision and standardization in traditional prescriptions of livestock traditional medicine. Hence, further studies on the active ingredients and their dosage measurements in ethnoveterinary preparations scientifically required as to guide their application.
The highest percentage of (63.4%) medicinal plants were used to treat cattle ailments could also be related to long experience rearing of cattle and the most prevalent diseases affecting cattle populations in the area. In a similar observation, Lulekal et al. [19] indicated that the largest use of ethnoveterinary plants for treating cattle ailments in Ankober District, Amhara Region. However, Sida schimperiana and Artemisia annua L. are being used as medicinal plants for treatment of rabies in dogs. The utilization of relatively few medicinal plants for treatment of poultry, small ruminants, equines and dogs could be associated with the low perception, the low occurrence of diseases affecting and less experience of the herbalists to these species. Like numerous reports on medicinal plants in Ethiopia [14,19,85], this study revealed also that infectious diseases like trypanosomiasis and blackleg were the most cited by informants. Listeriosis and coenuruses were treated by plant species which were uncommon to the usual list of medicinal plants from Ethiopia. The eight species Jatropha curcas, Carduus chamaecephalus, Datura stramonium, Arisaema enneaphyllum, Pycnostachyus abyssinica, Becium obovatum, Justica schimperiana, and Glycine wightii, showed to heal listeriosis and coenuruses in cattle and sheep.
Values Informant Consensus Factor (Fic) of different use categories of illnesses from this study showed that Fic values of reproductive system, infectious diseases, ectoparasite infestation and miscellaneous (snake biting, poising, bone fracture, fattening and constipation) categories were much higher than Fic value of the two illnesses (non-infectious and respiratory problems). This indicates that people had a greater agreement for plants used to treat diseases related to reproductive problems, infectious diseases and ectoparasite infestations. Consistent with this study, the highest share of similar plant use information within a community for disease of reproductive system and infectious category of [34]; however, in contrast to this study, Lulekal et al. [19] have reported that high ICF in the gastrointestinal disease category in their studies.
The present study determined different plants like Cyphostemma flavicans, Pentas schimperi, Eucalyptus globulus L., Croton macrostachyus, and so forth, scored highest fidelity values and should be further subjected to phytochemical and pharmacological investigation to prove their medicinal efficacy. The highest FL might be related to which the cited plant species has more healing power contributed to the presence of bioactive compounds for the respective ailments. Analysis of the preference ranking exercise also indicated that Azadirachta indica and Eucalyptus globulus L. were the most preferred ethnoveterinary medicinal plants used to treat blackleg, the most commonly reported disease in the study area. This could be attributed to the presence of bioactive compounds against the causative agents of blackleg in these species.
Non-ethnobotanical remedies used in animal disease management
The study found that other products than plants used by the Dawuro people in animal health management. In no case was the whole animals used, but rather body parts or by-products such as, the products and parts of a porcupine, hyena, cattle, bear and aphids (insects) were used by the community in ethnoveterinary practices. Eleven (11) non-plant remedies were used as source of veterinary therapeutic agents include hyena faece, wood ash, honeydew, oils, kerosene, local soap, salt, porcupine meat, dear faece, sharp hot iron or knife, milk, fermented kocho, porridge and the end product of Ensete ventricosum fluid traditionally called “Zaalima”. Porcupine meat and honey dew (aphids by product) are by far the main source of veterinary remedies: used to treat blackleg.
Nearly similar ethnoveterinary studies conducted elsewhere [35,39,92,93,94] share a similar concern on the knowledge of non-medicinal plant practices found that sharp hot iron or branding for treatment of blackleg and inflammation due to trauma, minerals from bones and salt are used to treat nutritional deficiencies, appetite promotion, and vegetable oil for managing bloat and dermatomycosis. However, hyena feaces, wood ash, dear faeces, porcupine meat, fermented kocho (C’aalaa unc’c’a), the end product of local kocho fluid (Zaalima), and honeydew were new or rarely reported non-plant remedies used in ethnoveterinary medicine in Ethiopia. The study undertaken by [92] indicated that traditional knowledge on the use of animals in traditional medicine (ethnomedicine or folk veterinary medicine) needs to be approached as an integrated and holistic structure by various branches of science in order to achieve a truly interdisciplinary understanding of the phenomenon of traditional medicine.
Generally, the documented ethnoveterinary remedies were the promising sources for the discovery of new low-cost drugs that are harmless to the environment and could help in conservation of biodiversity. Also, this study could help for program planners and policy makers to design their development strategy for animal health care policies and food sustainability; and overall socio-economic development of the poor rural people through cultivation and conservation of potential medicinal plant species in the area.