Performance and management of draught animals in agriculture in sub-Saharan Africa: a review

What Is a Working Equid? Analysis of Current Terminology and a Suggested Definition

Equids are engaged in myriad types of work across the world, with contexts and industries varying widely between high-, middle- and low-income countries as classified by the World Bank. Through a comprehensive abstract search and literature review, we examined the usage and context of terms associated with working equids in high-income countries (HICs), upper-middle-income countries (UMICs), lower-middle-income countries (LMICs), and low-income countries (LICs). Analysis showed that the search term used was significantly associated with World Bank country income classification. All search terms except two returned a significantly higher number of papers for higher-income countries compared to lower-income countries. The two exceptions were "working equid" and "draft equid", which returned significantly more papers for lower-income countries than higher-income countries. Both terms also returned papers from high-income and upper-middle-income countries, but these were always in the context of low-resource settings and rural or marginalised communities, of which we provide examples in the discussion. We propose that the term "working equid" should be used to describe "any equid engaged in physical labour that provides a significant or direct contribution to the economic livelihood, sustenance or support of the owner/user's family, typically within a low resource setting". Our review highlights the intricate interplay between socioeconomic factors and examines how equids are described in the literature. The lack of a universally accepted definition leads to challenges in policy formulation, resource allocation, and welfare standards development, particularly in LMICs and LICs where working equids are crucial to livelihoods. This study underscores the need for a more inclusive and comprehensive approach to terminology, advocating for future research to bridge linguistic and cultural gaps in understanding working equids globally. Such efforts are vital for equitable and effective welfare standards and policy development for these animals.

Serum Cortisol and Its Correlation with Leucocyte Profile and Circulating Lipids in Donkeys (Equus asinus)

The values for basal serum cortisol concentrations of horses are available in many studies. However, there are limited data about serum cortisol in donkeys. The present study aimed to determine the baseline values for serum cortisol, to evaluate the influence of age and pregnancy on its levels, and to correlate its values with leucocyte profile, serum cholesterol, and triglycerides. Serum samples were collected from 97 healthy donkeys. Cortisol was analyzed by chemo-luminescent assay. The median and the 2.5th and 97.5th percentiles of serum cortisol measured and calculated in all donkeys were 5.64, 3.40, and 10.54 µg/dL, respectively. Females (n.91) were divided into three groups: Group A (young), Group B (adult), and Group C (pregnant at the 9th−11th months). The effect of age and physiological status was investigated by the Mann−Whitney test. Group C showed significantly higher levels than Group B (p < 0.05). Significant correlations were found in Group B with monocytes (r = 0.37, p < 0.01) and triglycerides (r = 0.30, p < 0.05), and in Group C with monocytes (r = 0.79, p < 0.01), basophils (r = 0.6, p < 0.05), and neutrophil/lymphocyte ratio (r = −0.63, p < 0.05). Higher cortisol values related to late pregnancy are also found in this species. These preliminary results provide evidence for a relationship between cortisol and the immune system as well as cortisol and lipid metabolism modulated by age and pregnancy when parameters are within normal values.

The Use of Draught Animals in Rural Labour

Simple Summary

Although mechanisation has markedly reduced animal labour demand in agriculture, draught animals are still used in small production units located on terrains that do not favour agriculture mechanisation. Especially in Africa, Latin America, and Asia, they represent one of the main sources of sustenance for thousands of families who utilise animal labour in numerous agricultural tasks, such as ploughing and harvesting, as well as means of transport and hauling. Depending on the geographic area, the species involved are equids (horses, donkeys, and mules) and bovids (buffaloes and cattle). Draught animals proved to be sustainable in terms of global warming and the use of non-renewable energy as compared with agricultural machinery. However, critical points are the quality of human–animal interaction, due to the close contact between animals and humans while working, and the welfare of draught animals when transported and slaughtered, due to the high prevalence of injuries they suffer when subjected to these practices. Therefore, their use should be promoted in rural marginal areas where only low investments are usually feasible, and the energy of the animals can be obtained at a low cost by feeding them harvest residues and by-products.

Abstract

This study discusses scientific findings on the use of draught animals such as equids (i.e., horses, mules, and donkeys) and bovids (i.e., cattle and water buffaloes) in rural labours. Relevant peer-reviewed literature published between 1980 and 2021 was retrieved from CAB Abstracts, PubMed, ISI Web of Knowledge, and Scopus databases. Although animals were used to produce draught power since their domestication and are still being used for this purpose, mechanisation has markedly reduced animal labour demand in agriculture. However, the process was uneven across continents according to economic constraints, and draught animals are currently concentrated in small production units located on terrains that do not favour agriculture mechanisation in Africa, Latin America, and Asia. Generally, equids can work at rates similar to those of bovids or faster but can sustain the work for shorter periods of time. In addition, buffaloes possess tough hooves and resistance to disease that make them suitable for working in wetlands and clay soils. Draught animals allow a marked reduction of both GHG emissions and non-renewable energy consumption as compared with agricultural machinery. In addition, they may allow obtaining profits from otherwise non-usable lands. Therefore, their use should be promoted in rural areas where low investments are usually the only ones feasible, and the energy of the animals can be obtained at a low cost by feeding them harvest residues and by-products. However, more attention should be paid to the quality of human–animal interactions—due to the close contact between animals and humans while working—and to the welfare of draught animals when transported and slaughtered—due to the high prevalence of injuries they suffer when subjected to these practices.

Quantifying the Impact of Mounted Load Carrying on Equids: A Review

Simple Summary

The overloading of equids has become an important issue among veterinarians, trainers, riders, and welfare advocates. Increased weight carrying may have negative effects on biomechanical, physiological, biochemical, and behavioral parameters of equids during exercise, including causing gait asymmetry or lameness. It is important to determine how to carefully quantify the load-carrying capacity of both ridden horses and working equids. There are many options to assess the effect of loading on an animal’s body, but these have been inconsistently applied, making it difficult to reach a consensus, even for horses. This review summarises current knowledge of the load-carrying ability for horses and donkeys and the different parameters used to determine the effect of loading on these equids. Further research is needed to develop evidence-based guidelines for maximum loading in equids. Quantified loading limits or indicators of overloading could be used by stakeholders working with sports and pleasure horses and working equids to limit overloading and to improve the welfare of these animals.

Abstract

There are approximately 112 million working equids in developing countries, many of which are associated with brick kilns. Brick kilns and overloading are associated with welfare problems in working equids. Understanding equids’ abilities and influencing factors are important for both effective performance and welfare. Traditionally, measurement of the amount of ‘bone’ was used, and more recently, gait symmetry has been identified as a potential marker for loading capacity. Assessment of stride parameters and gait kinematics provides insights into adaptations to loading and may help determine cut-off loads. Physiological factors such as the ability to regain normal heart rates shortly after work is an important tool for equine fitness assessment and a more accurate measure of load-carrying capacity than absolute heart rate. Oxidative stress, plasma lactate, and serum creatine kinase activity are reliable biochemical indicators of loading ability. For monitoring stress, salivary cortisol is superior to serum cortisol level for assessment of hypothalamus-pituitary-adrenal axis and is related to eye temperatures, but this has yet to be interpreted in terms of load-carrying ability in equids. Further research is needed to standardize the evidence-based load-carrying capacity of working horses and donkeys.

Assessment of Phenotypic Characteristics and Work Suitability for Working Donkeys in the Central Highlands in Kenya

The study aimed to assess the phenotypic characteristics of donkeys and their suitability for work. Data were collected on age, sex, coat color, height at withers, body length, and heart girth from 360 randomly sampled donkeys raised in a highland agroecological system in Kenya between the months of June and September 2018. Data were analyzed using descriptive statistics and ANOVA with the sex of the donkey and age group treated as sources of variation. The weight of donkeys was estimated using a formulae incorporating body length and heart girth. The study reveals that the average weight of the working donkey in the central highlands of Kenya was 155.5 kgs ± SE 1.71. Their height at withers was 99.7 cm ± SEM 0.50, with a heart girth of 113.7 cm ± SEM 0.43 and a body length of 113.2 cm ± SEM 0.58. All these body measurements varied significantly by sex and age group (P < 0.001). Therefore, donkeys raised in Kenya had the same height but heavier, with longer body lengths and heart girth measurements when compared to other domesticated working donkeys in different parts of the world indicating genetic diversity, differences in ecogeographical conditions and husbandry practices. The majority (86%) of the donkeys were in good welfare conditions with moderate to ideal 86% body condition scores, minimal body lesions 5%, and lameness 18%. The results are useful for extension agents and donkey users when estimating optimal pack or cart loads in line with their welfare. The findings provide opportunities for future research on the reasons for phenotypic diversity between donkeys raised in Kenya and other parts of the world.

Household-oriented benefits largely outweigh commercial benefits derived from cattle in Mabalane District, Mozambique

In Sub-Saharan Africa, research aimed at improving household livelihoods through cattle often targets commercial benefits while neglecting household-oriented benefits. The latter are rarely articulated, and their comprehensive role in livelihoods is little understood by policymakers. The main aim of this study was to assess household-oriented benefits of cattle as a basis for formulating appropriate policies. Data were collected from 192 households selected through multistage random sampling in Mabalane District of Mozambique in 2009. The main objectives of cattle raising were identified and ranked in order of importance by using the analytical hierarchy procedure. The vast majority (98%) of households kept cattle primarily to derive various types of household-oriented benefits such as draft power, financing, insurance, saving, social status and bridewealth. Only 2% of households kept cattle mainly for commercial benefits. The households secured financing, insurance and saving primarily by capital accumulation through herd expansion, for example after a good crop harvest, using the profit to purchase a young calf, an ox or a heifer. Households reporting social prestige as an important objective for raising cattle were mainly those already with high social status. In Mabalane District, a large herd of cattle is considered evidence of one’s ability to manage communally owned resources. This suggests that the functions of draft power, financing, insurance and saving play important roles in the livelihoods of most of agro-pastoral households in Mozambique—arguably more important than meat and milk. The reliance on financing, insurance and saving benefits of cattle, as well as the low level of milk and meat marketing, could be explained by the low level of development within the district, exacerbated by the civil war that ended in the 1990s.

Circulating serovars of Leptospira in cart horses of central and southern Ethiopia and associated risk factors

Little work has been done on diseases of horses in Ethiopia or tropical regions of the world. Yet, Ethiopia has the largest horse population in Africa and their horses play a pivotal role in their economy as traction animals. A serological and questionnaire survey was therefore conducted to determine the circulating serovars of Leptospira and their association with potential risk factors in the cart horse population of Central and Southern Ethiopia. A total of 184 out of 418 cart horses from 13 districts had antibody titres of 1:100 or greater to at least one of 16 serovars of Leptospira species in Central and Southern Ethiopian horses. A significantly higher seropositivity (62.1%) was noted in horses from the highland agroecology followed by midland (44.4%) and lowland (39.8%). Serovar Bratislava (34.5%) was the predominant serovar followed by serovars Djasiman (9.8%), Topaz (5.98%) and Pomona (5.3%). Age and location proved to be associated with seropositive horses with older horses being more commonly affected and the districts of Ziway (Batu) (Apparent Prevalence (AP)=65.5%), Shashemene (AP=48.3%) and Sebeta (AP=41.4%) having the highest prevalence. Multivariable logistic regression found risk factors significantly associated with Leptospira seropositive horses were drinking river water (OR=2.8) and horses 7-12 years old (OR=5) and risk factors specifically associated with serovar Bratislava seropositive horses were drinking river water (OR=2.5), horses ≥13 years (OR=3.5) and the presence of dogs in adjacent neighbouring properties (OR=0.3). Dogs had a protective effect against seropositivity to serovars Bratislava and Djasiman, which may be due to their ability to control rodents. The high seroprevalence confirm that leptospirosis is endemic among horses of Central and Southern Ethiopia. The predominance of serovar Bratislava supports the idea that serovar Bratislava may be adapted to and maintained by the horse population of Central and Southern Ethiopia. This study emphasizes the need for further countrywide serological surveys and isolation of circulating leptospires in animals and humans in order to understand the role of horses in the epidemiology of this disease.

Hemato-biochemical responses to packing in donkeys administered ascorbic acid during the harmattan season

Experiments were performed to investigate the effect of ascorbic acid (AA) in reducing hemato-biochemical changes in pack donkeys during the cold-dry (harmattan) season. Six experimental donkeys administered orally AA (200 mg/kg) and six control donkeys not administered ascorbic acid were subjected to packing. Blood samples were collected from all donkeys for hematological and biochemical analyses. In the control donkeys, packed cell volume (PCV), erythrocyte count and hemoglobin concentration (Hb) decreased significantly (P<0.05) at the end of packing. In the experimental donkeys, there was no significant difference between the pre- and post-packing values of PCV, erythrocyte count and Hb. In the control donkeys, the neutrophil and neutrophil:lymphocyte ratio increased significantly (P<0.05) post packing, but in the experimental donkeys, the pre- and post-packing values were not significantly different. The eosinophil count increased significantly (P<0.05) in experimental and control donkeys post packing. In conclusion, packing exerted significant adverse effects on the hematological parameters ameliorated by AA administration. AA may modulate neutrophilia and induce a considerable alteration of erythroid markers in donkeys subjected to packing during the harmattan season.

Participatory study of medicinal plants used in the control of gastrointestinal parasites in donkeys in Eastern Shewa and Arsi zones of Oromia region, Ethiopia

Background

Gastrointestinal nematode infections constitute a threat to the health and welfare of donkeys worldwide. Their primary means of control is via anthelmintic treatments; however, use of these drugs has constraints in developing countries, including cost, limited availability, access to cheaper generic forms of variable quality and potential anthelmintic resistance. As an alternative, bioactive plants have been proposed as an option to treat and control gastrointestinal helminths in donkeys. This study aimed to use participatory methodology to explore donkey owner knowledge, attitudes and beliefs relating to the use of plant-based treatments for gastrointestinal parasites of donkeys in Ethiopia.

Results

In focus groups, 22/29 groups stated they knew of plants used for the treatment of gastrointestinal parasites in donkeys. All groups volunteered plants that were used in cattle and/or small ruminants. In total, 21 plants were named by participants. ‘Koso’ (Hagenia abyssinica) ‘Grawa’ (Vernonia amygdalina) and a mixed roots and leaves preparation were the most frequently named plant preparations. ‘Enkoko’ (Embelia shimperi) and ‘a mixture of roots and leaves’ were ranked highly for effectiveness in donkeys. However, ‘Grawa’ and ‘Koso’ were the highest ranked when taking into account both the rank position and the number of groups ranking the plant.

Thematic analysis of participants’ current attitudes and beliefs surrounding traditional plant-based remedies for gastrointestinal parasites revealed that anthelmintics obtained from clinics were generally favoured due to their ease of administration and perceived higher effectiveness. There was doubt surrounding the effectiveness of some plant-based treatments, but there were also perceived advantages including their low cost, ease of cultivation and availability. However, plant-based treatments were considered a “past trend” and people favoured “modern” medicine, particularly among the younger generation.

Conclusions

There was extensive knowledge of plant-based treatments for gastrointestinal parasites in livestock in Ethiopia. In donkeys, Koso (Hagenia abyssinica), Grawa (Vernonia amygdalina), Enkoko (Embelia shimperi) and ‘mixed roots and leaves’ were the most frequently named and/or highest ranked plants with reported efficacy against gastrointestinal parasites. Further in vitro and in vivo investigation of these plants is now required to determine viable alternatives for the treatment and control of gastrointestinal parasites in Ethiopia.

Ocular disease in working horses in Ethiopia: a cross-sectional study

Ocular disease is a frequent finding in working horses. This study aimed to estimate the prevalence and types of ocular pathology, and explore risk factors potentially associated with disease within a population of working horses in Ethiopia. In total, 1049 horses were selected from horses attending clinics run by the Society for Protection of Animals Abroad (SPANA). Each had an ophthalmic examination conducted under field conditions using a pen-torch. All owners completed a short questionnaire. The prevalence of ocular abnormalities was 23.5 per cent (95 per cent confidence interval (CI) 18.0 per cent to 30.1 per cent) and the percentage of horses with an abnormality in at least one eye was 43 per cent (95 per cent CI 28.7 per cent to 58.4 per cent), although this varied between towns. Mild eye pathology and end-stage disease with irreversible pathology were most common. There were significantly more eye abnormalities in the right eye compared with the left, and older horses were more likely to have ocular pathology. Only 55.1 per cent of owners had noticed there was an ocular abnormality present, and only 2.2 per cent had received any previous treatment for eye disease. Only 1.9 per cent presented to the clinic because of an eye problem. There appears to be either a lack of owner awareness, or a low perception of the importance of eye disease among owners.