Poisonous Plants Seem to Affect Livestock in the Borana, Southern Ethiopia: An Ethnic-Toxicological Approach

Introduction

Poisonous plant species in East Africa, including Ethiopia, have caused significant losses to livestock. Poisonous plants cause physical discomfort, decreased productivity, and even death in animals that are exposed.¹ Plant poisoning occurs when animals intentionally or unintentionally consume poisonous plants during feed shortages or when grazing for extended periods can poison livestock.² When edible forages are in short supply in the pastureland due to drought, animals are more vulnerable to ingesting poisonous plants.^3,4 Poisonous plants are often green and appealing to thirsty animals, but deficiency in phosphorus or vitamin A can make these issues worse. Factors such as susceptibility, species, consumption, and plant growth stage or section influence the prevailing effect on the victim.⁴

Plant toxins may be more difficult for animals to detoxify and may cause comparatively more harm due to the toxins’ metabolic effects when they are under nutritional stress. As a result, cautious supplemental feeding, and careful observation of grazing animals, and effective grazing management with prior knowledge of poisonous plants in the rangelands may all help to lessen the issue. This is due to the difficulty in distinguishing losses caused by diseases, accidents, predators, and the ingestion of poisonous plants. Disease, inadequate nutrition, and the consumption of poisonous plants can all contribute to poor reproductive performance and weight loss. Some of the negative effects of poisonous plants, such as birth defects, manifest years after ingestion.⁵

Toxic plants pose a significant threat to animals in Borana areas, leading to permanent or worsening liver or kidney disease, physical disturbance, decreased productivity, and even death. Livestock and livestock products are the primary sources of income in pastoral areas, but the lowlands are also home to potentially fatal diseases such as metabolic disorders and poisoning.⁶

Previous report indicated that the presence of toxic plants in the Borana zone. However, there is little information on the identification though there is some verbal evidence about the presence of some toxic plants.⁷ Therefore, the study was designed to identify the toxic plants in the study area as well as to assess the consequences of poisonous plants, identify factors that predispose livestock to major toxic plants, identify control and prevention methods practiced in the study area.

Materials and Methods

Study Area

The study was conducted in four districts of the Borana zone, located 570–775 km from Addis Ababa, the capital city of the country, bordering Northern Kenya and the Somali regional state of Ethiopia. Borana has four seasons, which are the long rainy season, the short rainy season, the cold dry season, and the dry season. The Borana receives bimodal rainfall but has an erratic and unreliable distribution. Seasonally, the rain falls in the two seasons, which are categorized as long rainy seasons from March to May and short rainy seasons from September to November. The other two seasons are the cold dry season, which includes the months from June to August, and the long dry season from December to February.⁸

Sampling Methods

The districts were purposively selected based on their proximity to our research center and the availability of toxic plants. The kebeles (the lower local administrations) and household was selected based on the simple random samplings.

Study Population and Sample Size

The 120 respondents that have livestock as well as animal health experts were interviewed and key focus group discussion was made.

Data Collection Method

Interviews with 120 people (30 from each kebele) were conducted through focus groups and a semi-structured questionnaire. During the study period, separate semi-structured interviews, field observations, and plant sample collection were conducted. During the interviews, all pertinent information was acquired, such as the names of the plants in the area, their toxic parts, the species of animals harmed, the age range of the exposed animals, the effects of poisoning, and how to prevent and control with plant poisoning. On the identification of toxic plants, the plant botany expert (Mr. Siraj Kelil) from agroforestry and natural resource department of Yabello Pastoral and Dryland Agriculture Research Center were participated. The collected plants were stored in the center (RefTP1) and the plants’ scientific names were determined using standard protocol, and the results were noted on the data collection sheet.

Data Analysis

After being organized using a Microsoft Excel spreadsheet, the names of the plants collected, the data gathered from questionnaires, and any other relevant information were analyzed using SPSS version 20. During the data analysis process, descriptive statistics were employed.

Results

Availability of Toxic Plants

Of those respondents 46 (38.33%) were female and 74 (61.67%) were male (Table 1) and specified 31 plants as poisonous plants. Out of the total of 120 interviewed individuals, 95% reported the existence of toxic plants.

Table 1 The Proportion of Respondents Reported the Presence of Poisonous Plants in Livestock About Districts According to the Sex Division of Respondents

Risk Factors of Exposure

Regarding putative poisonous plants to livestock the exposure to toxic plants was 41.1% rain season, 40.3% dry season, 16.6% (All seasons), and 1.7% (cold dry season based on the seasonal difference in decreasing order (Table 2). Most of those toxic plants occurred in forest areas/plateaus (42.9%) where animals frequently graze followed by Farmland (24.5%), Rangeland/roadside (15.7%), and dung decomposed fertile area (15.7%). Water points (0.8%) were the next areas where these toxic plants were claimed to be found, in decreasing order. The present study showed that shortage of feed in combination with nutritional deficiency (73.6%), sudden consumption of grass (22.8%), shortage of water (2.6%), and accidental body contact (0.8%) were major predisposing factors for animals to poisonous plants. Regarding poisoning of livestock by parts of plants, the study revealed that ingestion or contact of fresh evergreen and matured whole parts contributes 52.6%, followed by Leaves and seed (34.2%), fresh and dry leaves (11.4%), and seed (1.7%) of the toxic plant (Table 3).

Table 2 Summary of Risks of Exposure to Toxic Plants

Table 3 Summary of Poisonous Plants and Their Characteristics

The Reports of Toxic Plants in the Study Area

The main putative poisonous plants were Pavetta gardeniifolia (23.63%), Eragrostis cilianensis (17.72), Loudetia flavida (10%), Acokanthera schimperi (4.1), Capparis tomentosa (3.63), Solanum sp (3.2), Teclea salicifolia (2.27), Euphorbia tirucalli (1.36), reported in the study area. Common clinical symptoms complained of by the respondents about the poisonous plants were bloating, diarrhea, depression, incoordination, weakness, salivations, bloody urine, thorny tongue, and mouth, loss of appetite, restlessness, inability to stand, depression, and coma (Table 4).

Table 4 Effect of the Poisonous Plant on Livestock

Discussion

According to respondents, animal exposure to toxic plants was 41.1% rain season, 40.3% dry season, 16.6% all seasons, and 1.7% cold dry season based on the seasonal difference in decreasing order. This agrees with the findings of Horo Guduru Wollega,⁹ Wondo Genet,¹⁰ and peri-urban areas of Woliso and Wonchi,¹¹ and this could be because of the plant’s expansive growth and evergreening characteristics during the scarcity of animal feed. Those poisonous plants were reported to occur in forest areas/plateaus (42.9%) where animals frequently graze followed by farmland (24.5%), Rangeland/roadside (15.7%), dung decomposed fertile area (15.7%), and water points (0.8%) were the next areas where these toxic plants were claimed to be found, in decreasing order. The present study agrees with the study undertaken in Woliso and Wonchi towns by Sisay et al,¹¹ and is lower than the finding of Kassa and Abdi¹⁰ whose report showed 39.2% (rangeland) and 31.4% (farmland), and higher than forest (20.4%).

The present study showed that shortage of feed in combination with nutritional deficiency (73.6%), sudden consumption of grass (22.8%), shortage of water (2.6%), and accidental body contact (0.8%) were major predisposing factors for animals to poisonous plants. This also agrees with previous works,^10,12 and this might be because to the development of large forage plants that grazing animals can easily access.² While animals on a healthy diet are less likely to eat harmful plants and are better able to detoxify the tiny amount consumed, hungry animals are less discriminating about their foraging and consume significant quantities of toxic plants within a short period of time.¹³ A lack of nutrients can also raise the likelihood that livestock will consume poisonous plants.¹⁴ The outcome of this investigation was also consistent with the results of studies conducted in North Central America.¹⁵

Regarding poisoning of livestock by parts of plants, the study revealed that ingestion or contact of fresh evergreen and matured whole parts contributes 52.6%, followed by Leaves and seed (34.2%), fresh and dry leaves (11.4%), and seed (1.7%) of the toxic plant. This is in agreement with research findings from the Nekemte town area,¹⁶ central Ethiopia,¹⁷ and Wondo Genet.¹⁰

Cattle are the animals that are impacted most frequently, according to the participants. This is consistent with Kebede et al’s findings.¹⁶ Large animals are less picky and spend more time foraging. Small ruminants, on the other hand, require less feed but are less susceptible to poisonous plants,^16,17 more selective eaters, and spend more time looking for high-quality fodder.^18,19

Pavetta gardeniifolia (23.63%), Eragrostis cilianensis (17.72), Loudetia flavida (10%), Acokanthera schimperi (4.1), Capparis tomentosa (3.63), Solanum sp (3.2), Teclea salicifolia (2.27), Euphorbia tirucalli (1.36) were identified plants in the area. The majority of the plants found in this study were comparable to those found by Abebe et al (2012)²⁰ in the Borana Zone as well as Getahun and Beze’s²¹ recorded findings in Holeta. The subjects included in this study were reported with vernacular name of Gaaddallaa, Marra dhigaa, Qorsa diidaa, Mishingaa, Ardaa, Tabari, Ogora gaalaa, Hadha, Bobiya, Finchoo, Aannoo, Hidi, and Qobboo. These subjects were also included in the Abebe et al (2012) study conducted in the Borana Zone.²⁰

Several of the toxic plants found in the study area have also been reported to exist in other regions of Ethiopia. Datura stramonium, Sorghum bicolor, Solanum incanum Ricinus communis, and Amaranthus spp.),^9–11 Euphorbia tirucalli,^9,10 Olea Africana,⁹ Aloe species,¹⁰ and Euphorbia sp¹⁰ were reported from Woliso and Wonchi towns, Bako, Horo Buluk, and Afar, respectively.

Numerous variables, including the condition of the plant, its stage of growth, the portion consumed, its species, and the victim’s vulnerability, affect the dominant effect.⁴ According to the majority of respondents in the study area, animals poisoned by P. gardeniifolia do not exhibit any symptoms prior to death, and the presence of plant seeds in the animal’s stomach can corroborate the poisoning. Some respondents, however, expressed dissatisfaction over the fact that animals poisoned by the herb displayed symptoms such as diarrhea and bloating. Animals that consume Sorghum arundinaceum and Loudetia flavida urinate blood, and those that consume Hiddii gaagee go blind. This result is comparable to the reported results of Getahun and Beze²¹ in Holeta, as well as the findings of the Borana Zone byAbebe et al.²⁰

To include in the conclusion, In the study area, 31 poisonous plants for livestock were identified. Most frequently mentioned were Pavetta gardeniifolia, Loudetia flavida, Euphorbia tirucalli, Solanum somalense, Eragrostis cilianensis, Sorghum arundinaceum, Acokanthera schimperi, Capparis tomentosa, and Teclea salicifolia. As part of the recommendation, preventive measures and the use of remedies that are traditionally practiced by livestock owners should be supported. Intervention in the major toxic principles and phytochemistry of the different identified plant species is needed, and Further study on plant dynamics and compatibility with livestock production is required to overcome the impacts of poisonous plants.