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. 2024 Mar 22;19(3):e0295388. doi: 10.1371/journal.pone.0295388

Population, distribution, biomass, and economic value of Equids in Ethiopia

Girma Birhan Asteraye 1,2,3,4,*, Gina Pinchbeck 2, Theodore Knight-Jones 1,3, Klara Saville 5, Wudu Temesgen 1,3,4, Alemayehu Hailemariam 6, Jonathan Rushton 1,2
Editor: Chisoni Mumba7
PMCID: PMC10959329  PMID: 38517857

Abstract

Background

Equids play a crucial role in the Ethiopian economy, transporting agricultural inputs and outputs in the dominant subsistence agricultural systems and the critical link for value chains throughout the country. However, these species are often neglected in policies and interventions, which reflects the data and information gaps, particularly the contribution of working equids to Ethiopia.

Objective

To assess population dynamics, distribution, biomass, and economic value of equids in Ethiopia.

Materials and methods

Equine population data were obtained from the Ethiopian Central Statistics Agency (CSA) annual national agriculture surveys published yearbooks from 2004 to 2020. Parameters such as the number of effective service days and daily rental value were obtained from interviews and literature to estimate the stock monetary and service value of equids. Descriptive statistics were used to assess population dynamics and the geographical distribution was mapped.

Results

The estimated total Ethiopian equid population increased by more than doubled (by 131%) between 2004 and 2020 from 5.7 (4.9–6.6) million to 13.3 (11.6–15) million with 2.1 million horses, 10.7 million donkeys, and 380 thousand mules. Similarly, the number of households owning a working equid has increased. Equine populations are unevenly distributed across Ethiopia, although data were lacking in some districts of the country. The per human-capita equine population ranged from 0–0.52, 0–0.13, and 0–0.02 for donkeys, horses, and mules, respectively. The equid biomass was 7.4 (6.3–8.4) million Tropical livestock unit (TLU) (250 kg liveweight), 10% of total livestock biomass of the country. The stock monetary value of equids was USD 1,229 (651–1,908) million, accounting for 3.1% of total livestock monetary value and the services value of equids was USD 1,198 (825–1,516) million, which is 1.2% of Ethiopian 2021 expected GDP.

Conclusion

The Ethiopian equine population has grown steadily over the last two decades. Equids play a central role in transportation and subsistence agriculture in Ethiopia and contribute significantly to the national economy. This pivotal role is insufficiently recognized in national livestock investments.

Introduction

Equids are important for farming and non-farming households playing a key role in the national economy of Ethiopia [1], being a widely used mode of transport and draught power [2]. They also have important cultural value, being prominent in festivals and entertainment, with ceremonial roles in religious services such as weddings and funerals [25].

Working equids (horses, donkeys, and mules) play a significant role in generating household income [2, 6, 7]. For instance, Admassu and Shiferaw [3], demonstrated that equids provide 14% of annual household income, which accounted for 227 USD, which was comparable to other livestock species. In some parts of Ethiopia, the money gained from each working animal can support between five and twenty family members [2]. In a study around Addis Ababa households given a donkey by a local NGO reported an improvement in income and 84% of female donkey owners indicate that the donkey improved their lives [8]. In addition, owning a working animal is a major source of empowerment for women in terms of being freed from daily subsistence chores, and their wider status among the community [6]. In peri-urban and urban areas of Ethiopia working animals are used, mainly by youths, to generate an income by transporting merchandise (3,9,10). Furthermore, the gross value of equine transportation and draft services in Ethiopia was estimated at Ethiopian Birr 18,959 million [1] and 7,035 million [9] in 2010. Working equids were recognized by the UN as working livestock in 2016 and considered ‘critical to the livelihoods and resilience of millions of families throughout low- and middle-income countries’ [10].

Despite their considerable socioeconomic importance, equids are often neglected in livestock programs and investments [2, 3]. This leaves working equids vulnerable to low welfare standards and suboptimal output [2, 11, 12].

Ethiopia has the second largest working equid population after Mexico, with 40% of sub-Saharan Africa’s horses and donkeys and over 90% of the subcontinent’s mule population [13, 14] and several NGOs are working in Ethiopia to improve the lives of working equids [2].

A number of studies have highlighted the problems of obtaining accurate population statistics on working animals and the challenges in assessing their economic value [1416]. However, in Ethiopia much of the research up to now has been limited to the prevalence of some diseases and assessments of welfare [17, 18].

Since 1990/91 the Central Statistical Agency (CSA) of Ethiopia has carried out surveys and a solitary agricultural census and reported the annual population size for different livestock species [19]. Similarly, from 1961 to the present, FAOSTAT statistical data repository, provides free access concerning food and agricultural data from around the world [14].

Although the FAOSTAT database is an easily available source for understanding the size and distribution animals, it does not categorize sub-populations, such as by age or purpose. In addition, the FAOSTAT figures appear to be underestimates, particularly in Africa [17, 20]. Thus, we have used all the available published annual production yearbooks on livestock and livestock characteristics obtained from the CSA [19]. This study describes the population dynamics, distribution, biomass, and economic value of equids in Ethiopia. Understanding the size, distribution, and economic value of working equids will allow more informed decisions, particularly concerning investments in livestock development.

The Global burden of animal disease (GBADs) is a program, launched in 2018 [2123], aiming measuring and understanding the global burden of animal diseases. GBADs has been working on estimation of biomass and economic value across all livestock species to have common denominators to estimate direct and indirect losses caused by animal diseases worldwide. The present study is a part of this program and the findings with biomass and economic value of the equids could be used as initial data for further analysis of the burden of animal disease in working equids in Ethiopia. Moreover, the result includes important findings relevant to study the competition for grazing and the balance between natural resource use and the generation of sustainable activities for Ethiopia.

Methodology

Data sources and collection

Information on the size of Ethiopian livestock populations was obtained from CSA (https://www.statsethiopia.gov.et/our-survey-reports/) annual report series, the agricultural sample survey from 2004 to 2020. We used all available published yearbooks. In addition, donkey, horse, and mule population data from the FAOSTAT [13] website from 2004 to 2019 were used to show the trend difference compared to CSA.

CSA estimates the livestock data based on the information obtained from the livestock holders within the sampled agricultural households in the entire rural areas of the country, including all pastoralist areas. However, due to data sampling constraints and sometimes due to insecurities, livestock population data were not reported in some areas in 2020/21. The CSA data cover all domestic animals such as cattle, sheep, goat, camel, equine, and chickens by age, sex, and the purpose for which they are raised, such as transport, draught, and other uses in case of equids [19].

The price of a live animal (cattle, sheep, goats, and camels) was taken from the livestock market information system database of the Ministry of Trade and Industry (MoTI) of Ethiopia for the year 2021 [24]. Because MoTI does not report equids market prices in the system, seventeen (7 knowledgeable elders and 10 livestock market brokers) were interviewed for the current average market price and number of service days for transportation, from 17 districts where Brooke (an international NGO) operates to protect and maintain the health and welfare of equids in Oromia, Amhara, and Southern Nations Nationalities and Peoples (SNNPR) regions. These are dominant areas where donkeys, horses, and mules are used for transportation and draught power. These data are collected by local Brooke representatives and cluster team leaders after receiving oral consent from respondents. One interviewee per district was selected purposively based on their knowledge of use frequency and equids’ market price. In the interview, we asked about the average current market price of equids, and the average service days worked by equids each week, regardless of the number of hours worked per day. We then calculated the average market price and the average number of workdays. The interview guide is provided in S1 File.

The rental value of equids for transportation, as well as rental value and number of service days for draft usage, were obtained from a study done by Metaferia et al [9]. By considering the inflation rate in the last decade as indicated in the formula below,

RV2021=RV2011+RV2011*IR2011++RV2020+RV2020*IR2020

Where, RV = Rental value, IR = Average inflation rate of the year.

The reference rental value in 2011 was taken from Metaferia et al [9], while the country’s average inflation rates were obtained from CSA annual reports.

Data processing, analysis, and mapping

Stock monetary value was calculated by multiplying the total number of equid population by the current average market price in the year 2020. Equid service value was also determined by multiplying the total number of working equids (aged 3 years and above) by their average number of service days and rental value in 2020. Similarly, Biomass was calculated by using 250 kg as one Tropical livestock unit (1 TLU) [25] and multiplying it by the total equid population number.

The CSA [19] data disaggregated horses, donkeys and mules aged 3 years and above according to their services, mainly as transportation, draught, and others, and this categorization was used to estimate biomass, stock monetary, and service value. Working equids used for transporting goods or people by pulling carts or packing as transportation by the CSA, whilst working equids used for agricultural ploughing is categorized as draught and breeding equids as others. In addition, the existing livestock production system classifications of the Ministry of Agriculture (MoAG) of Ethiopia, Crop-livestock mixed (CLM) and Pastoral, as well as the list of administrative zones grouped under these production systems, were used to show the monetary value and biomass of equids in different production systems. The S2 File contains a complete dataset, including all information.

The geographical distribution of equids population was mapped using zone-level number of equids per capita (since the lower scale livestock data available are zone level), calculated as equids population divided by the human population, with human population data obtained from CSA [19]. Quantum GIS 3.16.11 software (QGIS Geographic Information System. Open-Source Geospatial Foundation Project. http://qgis.osgeo.org) was used to map equid populations.

The national and regional equine population dynamics were entered into Microsoft Excel. Simple descriptive statistics with tabulations and graphs were employed to show the trends. The equid population percentage change was calculated by dividing the difference between the initial equine population in 2004 and the population in 2020 by the initial population and multiplying by 100. Sampling uncertainty was expressed by calculating a 95% confidence interval (CI) from CSA equids population estimates and standard errors. Sensitivity analysis was checked by ± 20% to assess how individual input parameters influenced the output service value of equids.

Results

Equine population dynamics and service days

The total Ethiopian equid population has increased by more than double (131%) between 2004 and 2020, from 5.7 (4.9–6.6) million to 13.3 (11.6–15) million. CSA data showed roughly steady growth in the equine population between the year 2004 and 2020 (Fig 1).

Fig 1. Ethiopian equid population dynamics.

Fig 1

The largest growth of the equid population was recorded in 2006 (6.2 million to 6.4 million, increase by 19.2%) and the largest reduction was recorded in 2008 (7.7 million to 7.5 million, decrease by 1.8%) (Fig 1). The Oromia region has the largest share 40% of equine population in Ethiopia, followed by Amhara and SNNPR regions, which have 33.2% and 9.1% of equids, respectively (Table 1).

Table 1. The change in number of donkeys, horse, and mule population in different regions of Ethiopia.

Regions Donkey Population
(Thousand Head)
(Range)
Horse Population
(Thousand Head)
(Range)
Mule Population
(Thousand Head)
(Range)
2004 2020 Change (%) 2004 2020 Change (%) 2004 2020 Change (%)
Tigray 386.6 (292.2–481) 901 (690–1,112) 133 1.2 (0.1–2) 2.6 (0.08–5) 113 9.2 (0.4–18) 28.1 (15–41) 210
Afar 12.3 (3.2–21.3) 308.8 (121–497) 240 - - - 0.2 (0.06–0.3) - -
Amhara 1,400 (1,208–1,592) 3,725.4 (3,163–4,287) 167 257 (102–412) 490.2 (202–778) 90.5 89 (45.5–133) 199.8 (99–300) 125
Oromia 1,704 (1,427–1,981) 3,901 (3,263–4,539) 129 959.7 (561–1,359) 1,309.9 (794–1,826) 36.5 153.7 (95.7–212) 120.2 (25–215) - 22
Somali 91.5 (49–134) 978.8 (775–1,182) 97 - - - - 0.54 (0.06–1) -
B/Gumuz 37.5 (19.3–56) 62.6 (28.2–97) 67 - - - 1.8 (0.09–4) 3.5 (0.6–7) 95
SNNPR 278.4 (186–371) 818.6 (617–1,021) 194 298.7 (146–451) 345 (198–492) 15.5 63.5 (38–89) 45.5 (18–73) - 28
Gambela - 0.6 (0.1–1) - - - - - - -
Harari 6.3 (1.4–11) 14.6 (12–17.5) - - - - - - -
Dire Dawa 88 (4.3–11.4) 24.7 (2–47) - - - - - - -
National 3,930 (3,566–4,295) 10,792 (9,847–11,737) 175 1,5176 (1,063–1,971) 2,148 (1,535–2,762) 41 317.6 (240–395) 382.5 (240–525) 20

key: (-) No data\, (B/Gumuz) Benishangul Gumuz, (SNNPR) Southern nations nationalities and peoples region.

The increase in the population was also observed in each individual species with the highest increase observed in donkeys. Between 2004 and 2020, the donkey population increased by 24 and 9 fold in Afar and Somali pastoral areas, respectively, with a high percentage of change was observed starting from 2018 (Table 1).

Despite an overall increase in the number of horses and mules in the country. The reduction in the number of mules was documented in some reginal states (Table 1). CSA does not report the population number of both horses and mules in Afar, Somali, Harari, and Dire Dawa regions.

CSA data suggests a steady growth in the number of households that own working equid, with an increase of 154% between 2004 and 2020. The number of donkey holders showed the highest growth and was followed by horse holders with the value of 52% and 23.7% respectively. Between 2004 and 2020, the proportion of donkey owners increased from 25.1% to 38.1%. the proportion of horses and mules’ owners, on the other hand, are decreasing (Table 2).

Table 2. The proportion of working equid-holding households in total livestock-holding rural households in 2004 and 2020.

Equine holdings Year 2004 Year 2020
Number Percent Number Percent
Horse holdings 968,088 8.6% 1,470,534 7.8%
Donkey holdings 2,830,734 25% 7,200,897 38%
Mule holdings 295,594 2.6% 365,684 1.9%
Total equids holdings 4,094,416 36.2% 9,037,115 47.9%
Total livestock holdings 11,296,840 18,877,022

According to the interviewees, the effective service days for a donkey, horse, and mule are approximately 2.98 (2–4), 1.95 (1.3–2.6), and 1.89 (1.2–2.6) days per week on average for transportation, resulting in 155 (104–205), 101 (68–135), and 98 (62–135) days of service per year for donkeys, horses, and mules, respectively. Similarly, the market price for donkeys, horses and mules was estimated to be 74.8 (47.6–98), 151.8 (95.2–211.6), and 250 (148–333) USD, respectively. Because the data is insufficient, we did not estimate the effective service days of equids for draught usage.

Equid population distribution

The populations of donkeys, horses, and mules are unevenly distributed across Ethiopia. The majority of equids were reported in highland regions of the country, but still, considerable numbers of donkeys were found in pastoral areas. The per capita equine population ranges from 0 to 0.52 for donkeys, 0 to 0.13 for horses and 0 to 0.02 for mules in different administrative zones of the country (Figs 24). Generally, higher per capita of equine populations were observed in the zones grouped under crop livestock mixed system of the country where agricultural activities are prevalent.

Fig 2. Per capita distribution of donkeys.

Fig 2

Fig 4. Per capita distribution of mules.

Fig 4

Fig 3. Per capita distribution of horses.

Fig 3

Biomass and stock monetary value of equids

The average equine biomass was estimated to be 7.4 (6.3–8.4) million TLU, accounting for 10% of Ethiopia’s total livestock biomass (Table 3) (S1a Fig), and the total stock monetary value of equids was estimated to be 1,229 (651–1,908) million USD, accounting for 3.01% of Ethiopia’s total livestock economic value (Table 3) (S1b Fig). The total population, stock biomass and monetary value of different equine species, production system and their purpose are presented in Table 4.

Table 3. The equids population number, biomass, and the monetary value.

Species Population
(Head in million)
(Range)
Biomass
(Million TLU)
(Range)
Stock monetary value
(USD in million)
(Range)
Donkey 10.8 (9.8–11.7) 5.4 (4.9–5.7) 807.3 (469–1,149)
Horse 2.1 (1.5–2.8) 1.7 (1.2–2.2) 326.2 (146–584)
Mule 0.38 (0.2–0.5) 0.3 (0.17–0.5) 95.6 (36–175)
Total equids 13.3 (11.6–15) 7.4 (6.3–8.4) 1,229.1 (651–1,908)

Table 4. The number of equids population, their stock monetary value and biomass in the different production systems and purpose.

Species Classification Category Population
(Head in million)
Biomass
(Million TLU)
Stock monetary value
(USD in million)
(Range)
Donkey Production system CLM 8.9 4.4 664(423–868)
Pastoral 1.4 0.7 106(67–139)
Purpose Transport 7.4 3.7 556(354–727)
Draught 0.8 0.4 60 (38–78)
Other use 0.2 0.1 14(9–18)
Horse Production system CLM 2 1.6 302(189–420)
Pastoral 0.2 0.2 28(18–39)
Purpose Transport 1.4 1.1 210 (132–293)
Draught 0.3 0.2 41 (26–58)
Other use 0.1 0.1 14 (9–20)
Mule Production system CLM 0.4 0.2 86 (51–115)
Pastoral 0.01 0.01 2 (1–3)
Purpose Transport 0.3 0.2 73 (43–97)
Draught 0.1 0.03 12(7–16)
Other use 0.01 0.01 3 (1–3)

Note: The slight difference in the population numbers between Tables 3 and 4 arises from the process of classification by production system and purpose.

Transportation and draft services of equids

The service value of equine transportation and draft was estimated to be 1,197.6 (825–1,516) million USD. Most of the service value of equine transportation and draft was created by donkeys. Values by species and purpose of equids is presented in Table 5. The estimated service value of equids accounts for up to 1.2% of the 2021 year expected national GDP of the country. Sensitivity analysis was checked for each input variable for estimation of service value and the result found sensitive mainly for the change in population of equids.

Table 5. Estimates of service value of equids.

Equine species Services of Equines Population Service Days/year Rental services (USD/day) Value (Million USD/year)
Donkey Transportation 7,430,131 155 (104–205) 0.8 913.8 (613.2–1,208.6)
Draft (pair) 397,731 48 1.6 30.3
Horse Transportation 1,383,012 104 (68–135) 1.3 183.3 (123.4–244.9)
Draft (pair) 135,829 42 3.7 21.1
Mule Transportation 290,067 104 (62–135) 1.6 45.1 (28.5–62.1)
Draft (pair) 23,197 42 4.2 4.1
Services Value 1,197.6 (824.9–1515.6)

Discussion and conclusions

Ethiopia has a large equine population and play a central role in Ethiopia’s agricultural and transport systems. It could be said that working equids, particularly donkeys, are part of the critical infrastructure of Ethiopia e.g., essential for the functioning of a society and the economy [1, 3, 6].

Over the last fifteen years (2004–2020), the equid population has grown by more than double, this is primarily due to increases in the number of holdings, which may be related to the increase in human population. For instance, in rural Ethiopia, where 85% of the population of the country lives, when a new family is established, most begin living by owning a donkey as a working animal for transporting both farm and non-farm items because of poor road-network development. However, this could be due to an increase in awareness of owners to report the presence of large numbers of donkeys as livestock to the survey; because donkeys are not food animals in Ethiopia, their owners may not have previously reported them as livestock assets in the survey in the same way that cattle, sheep, or goats are, and this is supported by Starkey and Starkey [20].

The Brooke’s “Invisible Helpers” report [26] also highlighted fuel price rises have been one of the major drivers of the increased equine population alongside growing human populations and climate change. The increase in number of equids in the present study is consistent with the global trends that Norris et al [14] found between 1997 and 2018 for an increase in equid populations and demonstrates that this trend is continuing. In certain situations, CSA reports contradict some equid population growth trends [14, 20]. For instance, in 2006 an unexpected surge of equids population growth rate (19.2%, which is questionable) was reported. This might be due to the artifact in the CSA data collection or summarization process.

There is an increase in working equids ownership, primarily with donkeys. The donkey population make up the overwhelming majority of the equid population. This indicates the continued significant contribution of donkeys to individual households, and better resilience in different production systems. This is supported by Starkey & Starkey’s finding suggesting an increase in the number and demand for donkeys in sub-Saharan African countries [20]. CSA expand the geographic coverage of the survey area by including three zones of Afar region as of 2018 and six zones in Somali region as of 2019 which had not been included in the previous surveys. This suggests that the CSA data consistently underestimates the donkey population figure in previous years because CSA surveys have been confined to sedentary farming zones, excluding pastoral areas. This also results in a difference in the trend of equid population in the last three years between the CSA and FAOSTAT report.

Authors expected a reduction in the number of donkeys due to global demand for donkey skin, which is used to make traditional medicine ejiao [27], and reports of illegal cross-border donkey trade to Kenya [7]; however, Ethiopia subsequently closed the established donkey slaughterhouses before they began operation and banned donkey slaughtering following public affront for the business perceived as offensive to societal values and norms of the country, and while control of illegal donkey smuggling has begun, the impact on the donkey population in Ethiopia is not visible or perceptible in the CSA report thus far.

With regards to the horses and mules though, the global mule and horse population appears to be in a steady decline with a 64% and 0.6% reduction over the past twenty years, respectively [15]. The current study showed modest growth with some fluctuations in the numbers of horses and mules demonstrating the country still relies heavily on equids for transport and traction. Despite their overall population stability, the current study revealed the reduction in mules and horses in some regional states over time. This could be due to variation in market price between the neighbouring regions and potential movement and trade of mules and horses between the regions. Notably, the reason for the reduction of mules in some regions might be due to mules no longer being considered as prestigious animals in the community compared with previous times. As well, the importation of male breeding donkeys (‘‘Sinar”) from Sudan in the west to central Ethiopia is currently difficult due to political instability in the area. This could lead to shortage of male breeding donkeys which in turn influences a number of mules.

Equid populations are unevenly distributed in Ethiopia and a higher equid population is found under the crop livestock mixed system. This could be due to the CLM practiced in the highlands, which covers about 40% of the country’s land mass, and the dominant crop producing area; farmers require equids to transport their agricultural inputs and outputs in those areas. Similarly, the equids count per capita was higher in this system. However, the trend of equid population mainly donkeys showed remarkable growth in pastoral areas. This result is highly supported Wilson [28], stated as donkeys are second in water conservation mechanisms next to the camel among domestic animals, they can survive well in drought prone areas, and they are affordable as compared to camels.

The number of service days of equids varies depending on the production system and the owners’ living setup; for example, equids raised in rural and crop-producing areas are heavily involved in activities such as agricultural production and transportation.

The estimated equine biomass accounts for about 10% of the total livestock biomass of the country, contributing almost as much biomass as small ruminants and camels. This estimate may also be used as a denominator for various livestock-related analyses and species comparisons, including feed requirements, greenhouse gas emissions, and other environmental consequences like deforestation and land degradation.

The equines service value contributes about 1.2% of the 2021 year expected national GDP of the country. This indicates the considerable services of equids to the national economy mainly in delivering services for transportation and a source of draught power. The present service value estimate is double to the corresponding gross output estimated by Behnke’s [1] and almost five times the result by Metaferia et al. [9]. This could be mainly due to the growth in population of equids, the inflation in service value in the last decades, the difference in methodologies employed and the underestimation of equids working days per year in previous studies. The current study used part of the data and methodology of Metaferia et al. [9], who employed the UN System of National Accounts (UN-SNA) to estimate gross value added in livestock operations (or livestock GDP). However, we did not deduct intermediate consumption from the gross value of working equid output because most of the equine population lives in a rural, extensive system, and most equids rely on natural resources that still need to be appropriately valued. Even Metaferia et al. [9] deducted other livestock’s total intermediate consumption from the gross value of working equid output, which is questionable. Behnke et al. [1] used a production approach for estimating gross outputs. However, the technique they used to arrive at the figures is unclear. Moreover, their research used data from one administrative zone of Ethiopia, which may not be representative of the entire country. Since the economic role of equids are not yet studied systematically in Ethiopia the present estimated results are based on a rudimentary set of information, and it may have a degree of error. This is a very important area for future research. We recommend a review to improve estimation of livestock contribution to the national GDP of Ethiopia.

Despite the broad range of data and information that can be gained from the CSA data sets, there are limitations with the information on cart horses and mules and packing donkeys which are known to exist in urban and peri-urban areas, as no organized data is available for this sector nationally and this data set covers only the rural household-based holdings. Because of the above, our estimated stock monetary and service value lacks the economic contribution of carthorses, cart mule and packing donkeys in urban and peri-urban areas of the country which play a critical role in these local economies. Furthermore, there are no sources elucidating a production or husbandry classification system for working equids and their main production systems and environments under which they are maintained are needed. This kind of study will create the foundation for NGOs and policy makers to understand where and which equids are in the greatest need.

Supporting information

S1 File. Interview guide for current market price, number of services days and rental value.

(DOCX)

pone.0295388.s001.docx (17.2KB, docx)
S2 File. The dataset.

Which comprises equine and human populations at the zone level, the number of equids population in different production systems, equine populations by species, age and purpose, the number of equines holding rural households, market price and biomass.

(XLSX)

pone.0295388.s002.xlsx (77.7KB, xlsx)
S1 Fig. The proportion of equids biomass (a) and stock monetary value (b) with total livestock biomass and stock monetary value.

(DOCX)

pone.0295388.s003.docx (74.9KB, docx)

Acknowledgments

The authors acknowledge all cluster team leaders of Brooke Ethiopia for their assistance in equid market value and service day data collection. The authors also thank Brooke for co-supervising.

Data Availability

All relevant data are within the paper and its Supporting information files.

Funding Statement

GBA would like to acknowledge Brooke and Horse Trust for their funding this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

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Decision Letter 0

Chisoni Mumba

9 Mar 2023

PONE-D-23-03880Population, distribution, biomass, and economic value of equids in EthiopiaPLOS ONE

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Reviewer #1: Yes

Reviewer #2: Partly

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Reviewer #1: N/A

Reviewer #2: No

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Reviewer #2: No

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Reviewer #2: Yes

**********

5. Review Comments to the Author

Reviewer #1: Many thanks to the authors for submitting this interesting paper. I have three main comments and some smaller points made by line at the end of this review

- My main question reading this paper is why the results are not presented as ranges. The CSA data sampling methodology are included, and therefore a confidence interval or similar could be calculated. In a similar way, there is insufficient information about how other values are calculated, e.g. from key informant intervals. Presenting these interim figures, as well as the final figures, as ranges, would help the reader understand the range that the “real” values are likely to sit within. Some rudimentary sensitivity analysis would also be possible.

- The paper would benefit from ensuring that the methods section is reflected in the results section (see my comments, for example about the literature review, which is not really mentioned in the results)

- I think that the discussion section could benefit from being slightly more concise and focussing on how each aspect of the results adds to our knowledge. For me the key questions for the discussion are: How does this change how equids can be considered in Ethiopia, including discussion of previous estimates? What are the implications of the regional differences? How are the financial outputs associated with draft and transport interpreted alongside the market prices for each species, equids as a whole and alongside other livestock species? What do TLUs add to the conversation?

Line by line comments:

Line 46: insert space before “million” (twice). Check 131% number – percentages used in this way may be confusing so could say “more than doubled” or similar

Throughout, check spacing with references (that there is a space inserted before reference bracket)

Line 68: is there a reference for the statement about being comparable to other livestock?

Line 71: Rephrase – do you mean “… female donkey owners indicate that the donkey improved their lives”?

Line 73: Start a new sentence at “In peri-urban….”

Line 76: Poorly captured where? Your previous paragraph described multiple sources that describe the role of working equids. Are these studies poorly executed, or do you mean something else?

Line 79-80: can you clarify what you mean here? Ethiopian notifiable diseases? WOAH listed diseases? WOAH official disease status? These are three different things.

Line 81 onwards: check reference; this does not seem to be a UN document, but it reads as though this is a UN quote

Line 83, 85: try to avoid political geographical categorisations “developing” “sub-Saharan” etc

Line 89: this line is missing a reference

Line 95: Change have for has

Line 99: delete comma

Line 107: expand GBADs acronym. Check sentence structure

Line 113: I think this sentence needs a little more explanation – maybe this comes later in the paper

Throughout paper: Consider when you mean “economic” and when “monetary”: The economic value of an animal is more than its sale value

Methods

Throughout, and relevant to results – the CSA data are a sample – how is this reflected in the results? i.e. I would expect the population densities etc. to be presented as ranges, otherwise a discussion point on the decision on why this was not performed

Line 127: what is a holder?

Line 131: It would be useful to know the use categories that apply to equids

Line 147: suggest “performed” instead of “done”

Paragraph from Line 148: Please provide additional information –

- How many interviews? How were these distributed across demographic and geographical groups?

- How were interviewees selected? What does “conveniently” mean?

- How was consensus reached – how were these results analysed?

You used Google scholar for your literature search – how did you decide how many results to include? What were the criteria for inclusion? How was this information used? The search terms seem to contain duplicates i.e. as “donkey” is searched for, “cart donkey” would automatically be included. Why did you include “value” in “economic value” – for example, the term “economic contribution” would not be included in the search.

Line 174: use sheep and goats, not shoats

Sestion2.2.2 – the first paragraph is results. I would suggest tabulating this information. Line 188 – How did you decide to use this value? Why did you use a single value and not a range?

Line 192: this starts to answer my earlier question – can you explain how “transportation” and “draught” were defined?

Line 195: You earlier said that you asked interviewees about rental value – were these results not used? Which reference was the RV2011 taken from?

Section 2.2.3: which data were used for human populations?

Results:

Line 216: be specific about years i.e. between 20xx and 20xx- in the future it may be difficult for the reader to appreciate “the last 16 years”

Throughout results: please see my earlier comment about using percentages for changes over time.

Throughout: use consistent number of decimal places

Line 223: check that sentences are complete. I don’t think that you need this last sentence. It may be useful to identify these areas on a map

In table 1: How was rate of change calculated (should be in methods). What unit is used?

Figure 2: I am not sure what this shows in addition to table 1, and these are quite hard to read: for example having the key in the same order as the lines would help. Expand SNNP in the legend. Why are only 8 regions included for Donkeys – from table 1, this is the only species for which data are available in all regions, so it is confusing why regions without data are included for horses and mules, or is it that there are no equids in those regions?

Table 2: check headings – what does “households’ own equids” mean? What is the percentage figure? Do you need table 2 and figure 3?

Section 3.2 feels like it repeats some information from line 227-240

Table 4: In the text you describe “asset market value”, in the table “population/stock economic value”. Throughout the paper ensure consistency when describing different values

Figure 4; related to my comment on Figure 2 – areas where there are no data are presented as zero populations. Is this intentional? I would expect them to be marked differently. Check for distortion – maps on the RHS seem to be wider

Line 286: was this biomass figure calculated or identified in the CSA data

Line 289: “The majority of equids….” Check writing in some places for clarity. When you say “This appeared to be”, was this a number that you calculated? Throughout make sure that it is clear which values were calculated in the study, the language in this section could be tightened up, and this would help the reader understand your key points.

Figure 5: I would avoid pie charts in scientific writing like this. I think it would be helpful to show this as a table, with the raw numbers as well as percentages

Table 5: Can you explain the note in the legend? I don’t understand what this is referring to.

There is very limited information about the results of the literature search. How many articles were identified? How many were included in the results? Which were excluded and why?

Did you have regionally disaggregated results for population density for other livestock? This would be interesting as you would be able to see if there were geographical areas where working equids were proportionally more important compared with other species,

Section 3.4: ensure consistency for using equids / equines

Line 316: This first paragraph reads like introduction / conclusion. Why is the last sentence referenced when you have just presented these data.

Line 320: You don’t describe collecting these data about what working equids are used for – more information in the methods is needed

Line 234: As previously; how were these numbers calculated? What was the range of answers?

Line 326: do you mean table 6?

Line 327: change were to was. Check English in this paragraph i.e. “Most of the service value of equine transportation and draft was created by donkeys. Have you defined what you mean by “service value”? It might be worth explained what you mean by presenting this figure as a “gross” figure

Discussion

Line 349: Why did this bias exist?

Line 358: I am not clear if this increase is in line with an increase in all livestock owners – i.e. are you saying that a larger proportion of livestock owning households own working equids/donkeys, or that more households overall all own working equids/donkeys?

Line 372: I am not clear on the meaning of this sentence. It may be helpful to include in the methods some information about how FAOSTAT data are calculated

Paragraph 373: how does this relate to your results? Do you think that the donkey population would be larger without this trade? Were you expecting bigger increases? Or do you think this increase is to fuel the trade in other countries? The most recent Donkey Sanctuary reports cite Ethiopia as supplying the trade – they may have relevant references

Line 400: I thought that the number of holdings had increased? Or is this referring to a specific region/type?

Line 425 onwards: It may be helpful to expand this discussion. You used an estimate for weight based on similar equid systems. Are there any other data that can support this? With your links to Brooke (and other working equids NGOs) are there any other data sources that you could relate to these figures? When referencing the “TLU methods” in line 431 – I thought that you had used liveweights to identify TLU designations for the equine species? It would be helpful to discuss why biomass calculations (rather than just population numbers and monetary value) has been performed

Line 440: Can you describe why you have arrived at this conclusion?

Line 442: Perhaps this needs more explanation?

Line 443: Here when you refer to economic output are you only referring to transportation and draught work?

Line 445: This is the first time that it is mentioned that other authors have calculated equine output. How are the methodologies different? How do you know that the work was underestimated?

Line 451: This support my earlier comments on presenting ranges

Line 456: data “are”

Reviewer #2: this research presents the results of an investigation conducted as a part of the GBAD program, focusing on equids in Ethiopia.

the manuscript is well written, and results are presented with simple figures and tables as summaries.

some minor comments.

I'm wondering whether the section l95-114 are adequately placed in introduction, as they seem to give some rationale for methodlocial choices and background info

the ref 19 is missing in the text, around l 106

l 198: it seems that you could simplify the writing of the equation

l 234: why do you present % in the texte, and not in the table? quite confusing

l 336-344: it s already said in introduction

l 345 346. I could understand the link between the growth of equid and human population, but here you seem to speculate, do you have elements that show this? it is confusing, particularly as reading through the manuscript, we could doubt on the quality of original data used.

major concerns

my major concerns stem from the lack of clarity on:

- the data used and how they were used

- the lack of sensitivity analysis around the final numbers provided

- some assumption s made that are questionable.

section 2.1.1: I ma wondering how do you aggregate the 2 databases that you mention, as they seem to provide different information. how you manage the level of discrepancies between the 2 when it comes to equid population is unclear.

as for the market price, you dot detail if you van time series (which could match the population data)

l 148 onwards. we don't have any specification on how were conducted the interviews, how many.... as the market price appears to be a critical value for you to estimated the economic value, one could expect more details here.

the section 2.2.2. speaks of the exchange value to equids. reading through, we can see huge variation between estimates 157.7 or 445 USD for a multiple fro example. it s about 3 time more. While I can totally understand the difficulty to gather robust estimates, it raises red flags on the validity of the results, which are not weighted in anyway int he rest of the manuscript.

l 196: you consider the inflation rate, but we do not know where you identify the rate.

l 216: I'm questioning the likelihood of the results: an increase of 131% is huge, and it may be linked to at least 3 factors: a "real increase", a reporting bias (change in monitoring system over time for example), a lack of representativity of the sample. you have to reassure he reader on the validity of your findings.

section 3.2

one can see a difference between regions and population density. what we do not know, is the relationship between these 2 factors. I'm wondering if expressing the results in density/km2-ha would not be a way to combine the two, as we can speculate that some areas are of course more dense than others. the question I'm asking is what is the main determinant of equid density? the area or the human population?

how important is to present the results par area?

section 3.3

the economic value is estimated by multiplying the population and individual exchange values (I think). I already raised concerns about the initial estimates. additionally, I'm wondering f it really captures the economic value for many reasons:

first this is a snapshot, likely to be unrealistic if you position these values in a real market. a snapshot evaluation is probably mis-estimating the "true" value, as there will be market adjustments

overall we can speculate the the exchange value reflects the use value (see section 3.4), you coule probably discuss the links between the two.

this section 3.4. is actually interesting (See comment above), but lack of clarity, stemming for the lack of clarity in the methods.

one could put in parallel and discuss how the use and exchange values articulate.

l 434: you present a comparison between the economic values of different species, but we lack the outcomes of the findings.

**********

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Reviewer #2: No

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PLoS One. 2024 Mar 22;19(3):e0295388. doi: 10.1371/journal.pone.0295388.r002

Author response to Decision Letter 0


4 Jul 2023

Response to reviewers

We would like to say thank you for both reviewers and the editor for their constructive feedback and questions. We have tried to incorporate the feedback and provide clarification response for the questions as follows written in purple.

Thank you!

Response to reviewer #1: Many thanks to the authors for submitting this interesting paper. I have three main comments and some smaller points made by line at the end of this review

- My main question reading this paper is why the results are not presented as ranges. The CSA data sampling methodology are included, and therefore a confidence interval or similar could be calculated. In a similar way, there is insufficient information about how other values are calculated, e.g. from key informant intervals. Presenting these interim figures, as well as the final figures, as ranges, would help the reader understand the range that the “real” values are likely to sit within. Some rudimentary sensitivity analysis would also be possible.

- We have tried to present our result with range value for equid population, number of service days for transportation and market value from the interviewees. We didn’t include range value for equids used for draft service day estimates since we used data from Metaferia et al., (2010) and there was no indication of uncertainty in the research.

- The paper would benefit from ensuring that the methods section is reflected in the results section (see my comments, for example about the literature review, which is not really mentioned in the results)

- We have tried to incorporate the feedback related with methodologies (please see corrected version line 116-175)

- I think that the discussion section could benefit from being slightly more concise and focusing on how each aspect of the results adds to our knowledge. For me the key questions for the discussion are: How does this change how equids can be considered in Ethiopia, including discussion of previous estimates? What are the implications of the regional differences? How are the financial outputs associated with draft and transport interpreted alongside the market prices for each species, equids as a whole and alongside other livestock species? What do TLUs add to the conversation?

- We have tried to make more concise and related with the results of our work and include your comments to the discussion (please see corrected manuscript line 251-334)

Line by line comments:

Line 46: insert space before “million” (twice). Check 131% number – percentages used in this way may be confusing so could say “more than doubled” or similar (corrected line 46 and 47)

Throughout, check spacing with references (that there is a space inserted before reference bracket)

Checked and addressed, accordingly

Line 68: is there a reference for the statement about being comparable to other livestock?

The same authors (Admassu and Shiferaw 2011) made this statement

Line 71: Rephrase – do you mean “… female donkey owners indicate that the donkey improved their lives”?

Addressed, accordingly line 72.

Line 73: Start a new sentence at “In peri-urban….”

Addressed, accordingly line 75

Line 76: Poorly captured where? Your previous paragraph described multiple sources that describe the role of working equids. Are these studies poorly executed, or do you mean something else?

As indicated, there are few studies and most of the papers are reports and bulletins however, they do not adequately address the actual contribution of donkeys to household livelihoods or household income attributable to ownership and donkey use. In addition, despite the fact that donkeys are distributed and used in all parts and production systems of Ethiopia, the indicated studies were conducted around the central part and urban systems. And these studies are not enough to present donkeys' social and economic value compared to their number in the country and their contribution. That is why I wrote as “poorly captured”

Line 79-80: can you clarify what you mean here? Ethiopian notifiable diseases? WOAH listed diseases? WOAH official disease status? These are three different things.

I was meant to say WOAH listed diseases and I made necessary changes please see line 81

Line 81 onwards: check reference; this does not seem to be a UN document, but it reads as though this is a UN quote Corrected line 82-84

Line 83, 85: try to avoid political geographical categorisations “developing” “sub-Saharan” etc

Corrected as low- and middle-income countries' line 84

Line 89: this line is missing a reference - Corrected accordingly

Line 95: Change have for has - Corrected accordingly

Line 99: delete comma- Corrected accordingly

Line 107: expand GBADs acronym. Check sentence structure-Corrected accordingly

Throughout paper: Consider when you mean “economic” and when “monetary”: The economic value of an animal is more than its sale value

Yes, we agree and well accepted, corrected throughout the paper

Methods

Throughout, and relevant to results – the CSA data are a sample – how is this reflected in the results? i.e. I would expect the population densities etc. to be presented as ranges, otherwise a discussion point on the decision on why this was not performed

- We have tried to present our result with range value for equid population, number of service days for transportation and market value from the interviewees. We didn’t include range value for draft service day estimates of equids since we used data from Metaferia et al., (2010) and there was no indication of uncertainty in the research.

Line 127: what is a holder?

It was mean to say livestock holder, corrected accordingly line 122

Line 131: It would be useful to know the use categories that apply to equids.

The purpose categories, such as transport, draught, and other uses are incorporated line 127

Line 147: suggest “performed” instead of “done”- corrected accordingly

Paragraph from Line 148: Please provide additional information –

- Because MoTI does not report equids market prices in the system, seventeen (7 knowledgeable elders and 10 livestock market brokers) were interviewed for the current average market price and number of service days for transportation, from 17 districts where Brooke (an international NGO) operates to protect and maintain the health and welfare of equids in Oromia, Amhara, and Southern Nations Nationalities and Peoples (SNNPR) regions. These are dominant areas where donkeys, horses, and mules are used for transportation and draught power. These data are collected by local Brooke representatives and cluster team leaders after receiving oral consent. One interviewee per district were selected purposively based on their knowledge of use frequency and equids' market price. We used questions like "What is the current market price of equids?" In addition, the number of service days worked by equids each week was asked in the interview. (line 130-139)

- How were interviewees selected? What does “conveniently” mean?

Interviewees were selected purposively based on their knowledge of use frequency and equids' market price (line 137).

- How was consensus reached – how were these results analysed? The mean market price and the number of service days were calculated.

You used Google scholar for your literature search – how did you decide how many results to include? What were the criteria for inclusion? How was this information used? The search terms seem to contain duplicates i.e. as “donkey” is searched for, “cart donkey” would automatically be included. Why did you include “value” in “economic value” – for example, the term “economic contribution” would not be included in the search.

- - We decided not to utilize the data from the lit. review since we did not follow the necessary steps of the systematic literature search, the variation between the paper is vast, we agreed to use primary data (interview) for estimating the monetary value of equids.

Line 174: use sheep and goats, not shoats -Corrected, accordingly (line 126)

Sestion2.2.2 – the first paragraph is results. I would suggest tabulating this information.

The market value is included in result section as per the feedback (line 206-212)

Line 188 – How did you decide to use this value? Why did you use a single value and not a range?

We used the mean value of market price and number of service days from the interview and decided not to utilize the lit review results

Line 192: this starts to answer my earlier question – can you explain how “transportation” and “draught” were defined? Addressed as a following: -

The CSA (20) data disaggregated horses, donkeys and mules aged 3 years and above according to their services, mainly as transportation, draught, and others, and this categorization was used to estimate biomass, stock monetary, and service value. Working equids used for transporting goods or people by pulling carts or packing as transportation by the CSA, whilst working equids used for agricultural ploughing are categorized as draught and breeding equids as others (line 154-159).

Line 195: You earlier said that you asked interviewees about rental value – were these results not used?

Which reference was the RV2011 taken from? Corrected (line 140-146)

The rental value of equids for transportation, as well as rental value and number of service days for draught usage, were obtained from a study done by Metaferia et al (30). By considering the inflation rate

The reference rental value in 2011 was taken from Metaferia et al (30), while the country's average inflation rates were obtained from CSA annual reports.

Section 2.2.3: which data were used for human populations? Addressed as a following:- (line 163-167)

The geographical distribution of equids population was mapped using zone-level number of equids per capita (since the lower scale livestock data available are zone level), calculated as equids population divided by the human population, with human population data obtained from CSA (20). Similarly, equid population per km2 land area was mapped at the zone level taken from MoAG (31).

Results:

Line 216: be specific about years i.e. between 20xx and 20xx- in the future it may be difficult for the reader to appreciate “the last 16 years” -corrected Accordingly – line 178-179

Throughout results: please see my earlier comment about using percentages for changes over time.

Corrected throughout the paper

Throughout: use consistent number of decimal places

Corrected throughout the paper

Line 223: check that sentences are complete. I don’t think that you need this last sentence. It may be useful to identify these areas on a map

we agree it already included in the tables and corrected in the document

In table 1: How was rate of change calculated (should be in methods). What unit is used?

we have changed in to percentage change: To calculate the equid population growth change, we used the difference between the initial equine population in 2004 and the population in 2020, then divided by the initial population and multiplied by 100. And I have incorporated it in the methods (please see table 1)

Figure 2: I am not sure what this shows in addition to table 1, and these are quite hard to read: for example having the key in the same order as the lines would help. Expand SNNP in the legend. Why are only 8 regions included for Donkeys – from table 1, this is the only species for which data are available in all regions, so it is confusing why regions without data are included for horses and mules, or is it that there are no equids in those regions?

Yes, we agree there is no difference between Table 1 and Figure 2, Figure 2 is removed. However, in response to your question, "Why only 8 regions?" some data are lacking in some regions in CSA report and it’s not captured by the graph.

Table 2: check headings – what does “households’ own equids” mean? – it was meant to say equid holders -corrected (line 204) What is the percentage figure? It is to show the change in number of equine holders between the years.

Do you need table 2 and figure 3?

Because it has the same messages with table 2 we removed fig 3

Section 3.2 feels like it repeats some information from line 227-240 Corrected please see 215-220)

Table 4: In the text you describe “asset market value”, in the table “population/stock economic value”.

Corrected accordingly Throughout the paper

Figure 4; related to my comment on Figure 2 – areas where there are no data are presented as zero populations. Is this intentional? Yes, we tried to present them with the range. I would expect them to be marked differently (we can present differently though). Check for distortion – maps on the RHS seem to be wider please see page 7 amended version.

Line 286: was this biomass figure calculated or identified in the CSA data

We have calculated the biomass using the CSA population data and the TLU conversion from the literature (please see line 151-135)

Line 289: “The majority of equids….” Check writing in some places for clarity. When you say “This appeared to be”, was this a number that you calculated? Throughout make sure that it is clear which values were calculated in the study, the language in this section could be tightened up, and this would help the reader understand your key points.

we have made necessary changes as per the feedback

Figure 5: I would avoid pie charts in scientific writing like this. I think it would be helpful to show this as a table, with the raw numbers as well as percentages

was meant to show the difference by comparing with other livestock species of the country. Yes, I accept the feedback and include the point in the text line 228-232

Table 5: Can you explain the note in the legend? I don’t understand what this is referring to.

It was meant to express if there is a variation in number of population of equids in different production system with the total it is because we used the categorization of zone using MoAG and the number is from CSA.

There is very limited information about the results of the literature search. How many articles were identified? How many were included in the results? Which were excluded and why?

As I indicated above, because we did not follow the proper steps of literature search and because we want relay on the primary data (interview) for estimation of economic value of equids, we decides not to use the data from literature review.

Did you have regionally disaggregated results for population density for other livestock? This would be interesting as you would be able to see if there were geographical areas where working equids were proportionally more important compared with other species,

I didn’t but I know colleagues in GBADs are working on it.

Section 3.4: ensure consistency for using equids / equines

Line 316: This first paragraph reads like introduction / conclusion. Why is the last sentence referenced when you have just presented these data.

Deleted as per the feedback.

Line 320: You don’t describe collecting these data about what working equids are used for – more information in the methods is needed

Line 324: As previously; how were these numbers calculated? What was the range of answers?

The mean value is calculated and expressed with range

Line 326: do you mean table 6? Corrected included in the methods with amended version line 128-140

Line 327: change were to was. Check English in this paragraph i.e. “Most of the service value of equine transportation and draft was created by donkeys. Corrected

Have you defined what you mean by “service value”? It might be worth explained what you mean by presenting this figure as a “gross” figure – “gross” was to say the value from total population but we have now used service value

Discussion

Line 349: Why did this bias exist?

this could be due to an increase in awareness of owners to report the presence of large numbers of donkeys as livestock to the survey; because donkeys are not food animals in Ethiopia, their owners may not have previously reported them as livestock assets in the survey in the same way that cattle, sheep, or goats are, and this is supported by Starkey and Starkey. Line 258-261

Line 358: I am not clear if this increase is in line with an increase in all livestock owners – i.e. are you saying that a larger proportion of livestock owning households own working equids/donkeys, or that more households overall all own working equids/donkeys? Corrected – it was to say a larger proportion of livestock owning households own working equids

Line 372: I am not clear on the meaning of this sentence. It may be helpful to include in the methods some information about how FAOSTAT data are calculated. It is now corrected- but until 2017 FAOSTAT used to report the data from CSA but after that even though I don’t know the reason starting from 2018 they start to report using imputation.

Paragraph 373: how does this relate to your results? Do you think that the donkey population would be larger without this trade? Were you expecting bigger increases? Or do you think this increase is to fuel the trade in other countries? The most recent Donkey Sanctuary reports cite Ethiopia as supplying the trade – they may have relevant references- corrected please see 280-286 amended version

Line 400: I thought that the number of holdings had increased? Or is this referring to a specific region/type?

Yes, the number of holdings is increased, but there are some reductions in number of mules holdings

It’s now corrected.

Line 425 onwards: It may be helpful to expand this discussion. You used an estimate for weight based on similar equid systems. Are there any other data that can support this? With your links to Brooke (and other working equids NGOs) are there any other data sources that you could relate to these figures? When referencing the “TLU methods” in line 431 – I thought that you had used liveweights to identify TLU designations for the equine species? It would be helpful to discuss why biomass calculations (rather than just population numbers and monetary value) has been performed

We have tried but we could not get data related with biomass of equids

Can you please see line 309-313 amended version

Line 440: Can you describe why you have arrived at this conclusion? It is now Corrected I was meant to say as the country can benefit with low input

Line 442: Perhaps this needs more explanation? This is the work that I mentioned which is conducted by other GBADs colleagues

Line 443: Here when you refer to economic output are you only referring to transportation and draught work? Yes, it the service value of equids it is now corrected

Line 445: This is the first time that it is mentioned that other authors have calculated equine output. How are the methodologies different? How do you know that the work was underestimated? These are the reports from ministry of trade and finance and IGAD not proper studies their methodologies are not well described, that is why I did not indicate before.

Line 451: This support my earlier comments on presenting ranges corrected most the results are now supported with range

Line 456: data “are” corrected.

Response to reviewer #2:

This research presents the results of an investigation conducted as a part of the GBAD program, focusing on equids in Ethiopia.

the manuscript is well written, and results are presented with simple figures and tables as summaries.

some minor comments.

I'm wondering whether the section l95-114 are adequately placed in introduction, as they seem to give some rationale for methodlocial choices and background info

It is to give some intro about the data I used for the paper, I can still edit as per your feedback

the ref 19 is missing in the text, around l 106

That is my statement that is why I did not put a reference

l 198: it seems that you could simplify the writing of the equation

corrected please line 140-146

The rental value of equids for transportation, as well as rental value and number of service days for draught usage, were obtained from a study done by Metaferia et al (30). By considering the inflation rate in the last decade as indicated in the formula below,

RV2021=RV2011+(RV2011*IR2011)+⋯+RV2020+(RV2020*IR2020)

Where, RV=Rental value, IR= Average inflation rate of the year

The reference rental value in 2011 was taken from Metaferia et al (30), while the country's average inflation rates were obtained from CSA annual reports.

l 234: why do you present % in the text, and not in the table? quite confusing

My mistake corrected accordingly please line 188-194 amended version

l 336-344: it s already said in introduction

Corrected accordingly line 250 amended version

l 345 346. I could understand the link between the growth of equid and human population, but here you seem to speculate, do you have elements that show this? it is confusing, particularly as reading through the manuscript, we could doubt on the quality of original data used.

corrected please see 253-269

Over the last fifteen years (2004-2020), the equid population has grown by more than double, this is primarily due to increases in the number of holdings, which may be related to the increase in human population. For instance, in rural Ethiopia, where 85% of the population of the country lives, when a new family is established, most begin living by owning a donkey as a working animal for transporting both farm and non-farm items because of poor road-network development. However, this could be due to an increase in awareness of owners to report the presence of large numbers of donkeys as livestock to the survey; because donkeys are not food animals in Ethiopia, their owners may not have previously reported them as livestock assets in the survey in the same way that cattle, sheep, or goats are, and this is supported by Starkey and Starkey (21).

major concerns

my major concerns stem from the lack of clarity on:

- the data used and how they were used

- the lack of sensitivity analysis around the final numbers provided

- some assumption s made that are questionable.

section 2.1.1: I ma wondering how do you aggregate the 2 databases that you mention, as they seem to provide different information. how you manage the level of discrepancies between the 2 when it comes to equid population is unclear.

I was using both CSA and FAOSTAT to show the trend difference compared to CSA.

I corrected it please see line 121-122

as for the market price, you dot detail if you van time series (which could match the population data)

I wish I could show the trend with the market price as well but the market price data are lacking/not sufficient that is why we use the data from the interview please see line 132-140

l 148 onwards. we don't have any specification on how were conducted the interviews, how many.... as the market price appears to be a critical value for you to estimated the economic value, one could expect more details here.

my mistake, corrected please see line 132-140

Because MoTI does not report equids market prices in the system, seventeen (7 knowledgeable elders and 10 livestock market brokers) were interviewed for the current average market price and number of service days for transportation, from 17 districts where Brooke (an international NGO) operates to protect and maintain the health and welfare of equids in Oromia, Amhara, and Southern Nations Nationalities and Peoples (SNNPR) regions. These are dominant areas where donkeys, horses, and mules are used for transportation and draught power. These data are collected by local Brooke representatives and cluster team leaders after receiving oral consent. One interviewee per district were selected purposively based on their knowledge of use frequency and equids' market price. We used questions like "What is the current market price of equids?" In addition, the number of service days worked by equids each week was asked in the interview.

the section 2.2.2. speaks of the exchange value to equids. reading through, we can see huge variation between estimates 157.7 or 445 USD for a multiple fro example. it s about 3 time more. While I can totally understand the difficulty to gather robust estimates, it raises red flags on the validity of the results, which are not weighted in anyway in the rest of the manuscript.

- We decided not to utilize the data from the lit. review since we did not follow the necessary steps of the systematic literature search, the variation between the paper is vast, we agreed to use primary data (interview) for estimating the monetary value of equids.

l 196: you consider the inflation rate, but we do not know where you identify the rate.

corrected please see line 147-148 � The reference rental value in 2011 was taken from Metaferia et al (26), while the country's average inflation rates were obtained from CSA annual reports.

l 216: I'm questioning the likelihood of the results: an increase of 131% is huge, and it may be linked to at least 3 factors: a "real increase", a reporting bias (change in monitoring system over time for example), a lack of representativity of the sample. you have to reassure the reader on the validity of your findings.

I have tried to discuss the possible reasons can you please see line 255-271 for me it can be both the real increase and also reporting bias as there are unrealistic surges are there in the trend and I mentioned this in the discussion

section 3.2

one can see a difference between regions and population density. what we do not know, is the relationship between these 2 factors. I'm wondering if expressing the results in density/km2-ha would not be a way to combine the two, as we can speculate that some areas are of course denser than others. the question I'm asking is what is the main determinant of equid density? the area or the human population?

how important is to present the results par area?

The main determinant for equid density is human population and we have made necessary changes as per your question and feedback please see line 216-229.

section 3.3

the economic value is estimated by multiplying the population and individual exchange values (I think). I already raised concerns about the initial estimates. additionally, I'm wondering f it really captures the economic value for many reasons:

first this is a snapshot, likely to be unrealistic if you position these values in a real market. a snapshot evaluation is probably mis-estimating the "true" value, as there will be market adjustments

overall we can speculate the the exchange value reflects the use value (see section 3.4), you coule probably discuss the links between the two.

I have changed the word economic value to monetary value as it is more general and it describe our result better and we have indicated the result with range value. Please see line 227-247.

this section 3.4. is actually interesting (See comment above), but lack of clarity, stemming for the lack of clarity in the methods. Corrected, I have now included in the method section please see line 150-153

one could put in parallel and discuss how the use and exchange values articulate.

l 434: you present a comparison between the economic values of different species, but we lack the outcomes of the findings. Corrected as per the feedback, I was trying to compare and show the difference in biomass and monetary value between species by considering the data from GBADs colleagues, but I now removed the point because I didn’t touch in my result and even methods.

Response for Editorial comments

1. We follow PLOS one authors guidelines to meet editorial requirement.

2. We removed this reference because we don’t use it anymore.

4. The map is our work and we have included it in the method section please see line 163-167

The geographical distribution of equids population was mapped using zone-level number of equids per capita (since the lower scale livestock data available are zone level), calculated as equids population divided by the human population, with human population data obtained from CSA (20). Quantum GIS 3.16.11 software (QGIS Geographic Information System. Open-Source Geospatial Foundation Project. http://qgis.osgeo.org ) was used to map equid populations.

I thank you both reviewers and the editor, this will strengthen our paper.

Respectfully, Girma

Attachment

Submitted filename: Response to editorial comment.docx

pone.0295388.s004.docx (22.5KB, docx)

Decision Letter 1

Chisoni Mumba

6 Oct 2023

PONE-D-23-03880R1Population, distribution, biomass, and economic value of equids in EthiopiaPLOS ONE

Dear Dr. Asteraye,

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Reviewer #3: All comments have been addressed

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Reviewer #1: Thank you for providing this improved manuscript. Please note that it would be helpful to provide a version with marked up tracked changes that show where changes have been made to the document, not wholesale deletions and reinsertions. Additionally it would be helpful if the responses consistently contained line numbers that refer to the most recent version of the manuscript. It is very time consuming to re-review a document presented in this way. The document I have access to has four different versions of the paper -I have based this review on the one starting on page 68. This means I may miss some changes, as I cannot reference them by line number, or comment on parts of the manuscript that are unchanged.

Generally, two main comments still require some changes. It is good to see that the suggestion about including a numerical range to represent the sampling uncertainty. But what does the ranges presented represent and how were they calculated? – confidence intervals? Standard deviation? These should inform your sensitivity analysis, which in insufficiently described in the methods, results and discussion.

Some additional points

Line 68: In this case “demonstrated that equids provide 14% of annual household income … which was comparable to other livestock species in that study”.

Line 77: This still feels like a contradiction to me and would benefit from some critical thinking (with reference to line 90-91 as well)

Line 81: The manuscript does not reflect the response to reviewers

Line 173: suggest: “The equid population percentage change was calculated by dividing the difference between the initial equine population in 2004 and the population in 2020 by the initial population and multiplying by 100”

Table 2: explain what these numbers are a percentage of – all equid holders or all livestock holders. Make sure that the title represents the tables contents – it does not show the change, simply the populations in the two years

Table 4 appears to repeat table 3 (although the numbers are slightly different). Can you include a clear explanation?

Line 212: “Because the data is insufficient, we did not estimate the effective service days of

equids for draught usage.” – but then this seems to have been done in table 5

Line 267: Which scientific growth rate estimates are you referring to?

Line 315 onwards: I think it would still be beneficial to discuss these other estimates in more depth, even if they do not have clearly defined methodologies (even including in the manuscript that the methodologies are not clearly defined.)

The manuscript would benefit from a thorough proof read: e.g. consistency of decimal places, some verb agreements, use of data as either a singular or plural throughout, not a mix

Reviewer #3: (No Response)

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PLoS One. 2024 Mar 22;19(3):e0295388. doi: 10.1371/journal.pone.0295388.r004

Author response to Decision Letter 1


10 Nov 2023

Dear reviewer-1: Please accept my apologies for making the review challenging; I will work properly after this. Dear editor, apologise for not returning my response within fortnights, I was out of the city for data collection, and the internet connectivity was very limited, which made it difficult for me to send my response in time. I appreciate your patience and understanding in this regard. Thank you.

Please refer to the indicated line numbers in the recent version of the manuscript and here in this box I have included your questions with my responses.

Generally, two main comments still require some changes. It is good to see that the suggestion about including a numerical range to represent the sampling uncertainty. But,

• What does the ranges presented represent and how were they calculated? – confidence intervals? Standard deviation? These should inform your sensitivity analysis, which in insufficiently described in the methods, results and discussion.

Okay, the range shown is a 95% confidence interval (CI); because the CSA estimates livestock population and indicates a standard error, we calculated the confidence interval to take into account the uncertainty associated with sampling variability; we have calculated using the formula

Confidence Interval = The equids population mean ± (Z * Standard Error)

- Mean: The equids population mean

- Z: ≈ 1.96 as CSA calculated the CI at 95%

- Standard Error: the SE value from CSA

The sampling uncertainty was expressed by calculating a confidence interval from CSA livestock population estimates and standard errors. This is now included in the method section line 173-74.

Some additional points

Line 68: In this case “demonstrated that equids provide 14% of annual household income … which was comparable to other livestock species in that study”.

Yes, as per the result of Admassu and Shiferaw (2011), working equids contribute 14% of household income and which was comparable to other livestock species. I accept the comment - line 69

Line 77: This still feels like a contradiction to me and would benefit from some critical thinking (with reference to line 90-91 as well)

I have incorporated necessary change for the sentence as per the comment received - line 81-82

Line 81: The manuscript does not reflect the response to reviewers

I have made changes to the paragraph ( line 79 to 83) based on the feedback I received.

Line 173: suggest: “The equid population percentage change was calculated by dividing the difference between the initial equine population in 2004 and the population in 2020 by the initial population and multiplying by 100”

Thank you and I accept your suggestion fully, and addressed, accordingly, please see line (170-72)

Table 2: explain what these numbers are a percentage of – all equid holders or all livestock holders. Make sure that the title represents the tables contents – it does not show the change, simply the populations in the two years

This proportion was determined based on total livestock holdings, and I have updated the title to reflect this (line 203-4).

Table 4 appears to repeat table 3 (although the numbers are slightly different). Can you include a clear explanation?

As mentioned in the methodology section, the CSA separated the equine population based on species, sex, and purpose. This information was used to calculate the biomass and the monetary value of the stock. The slight difference in the number between the total (Table 3) and the categorized (Table 4) is a result of the disaggregation process. I have included the explanation for the difference, please see line 237-8.

Line 212: “Because the data is insufficient, we did not estimate the effective service days of equids for draught usage.” – but then this seems to have been done in table 5

As it indicated in method section (line 140-42) rental value and number of service days for draft usage, were obtained from a study done by Metaferia et al (2010) for calculation to estimates of service value of equids. Therefore, the draught usage service days indicated in table 5 are from Metaferia et al (2010). Kindly, If I am expected to write under a table 5 as a note, I can do that.

Line 269: Which scientific growth rate estimates are you referring to?

I should not have used the word "scientific" in that sentence. I was referring to the unexpected growth of the equid population in 2006 with 19.2%, which is quite different from the rest of the consecutive years, and if the equid birth rate is one foal per year (which is equivalent to a 100% foaling rate), this would not result in the type of growth CSA indicated in 2006. Please see (lines 274 and 75) for a correction.

Line 315 onwards: I think it would still be beneficial to discuss these other estimates in more depth, even if they do not have clearly defined methodologies (even including in the manuscript that the methodologies are not clearly defined.)

I have tried to include their methods and discuss with our result, can you please see line 321-330

The manuscript would benefit from a thorough proofread: e.g. consistency of decimal places, some verb agreements, use of data as either a singular or plural throughout, not a mix- I attempted to make decimal places consistent manly in the tables by approximating.

Attachment

Submitted filename: Response to reviewers_2.docx

pone.0295388.s005.docx (27.6KB, docx)

Decision Letter 2

Chisoni Mumba

22 Nov 2023

Population, distribution, biomass, and economic value of equids in Ethiopia

PONE-D-23-03880R2

Dear Dr. Asteraye,

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PLOS ONE

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Reviewers' comments:

Acceptance letter

Chisoni Mumba

10 Jan 2024

PONE-D-23-03880R2

PLOS ONE

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Associated Data

    This section collects any data citations, data availability statements, or supplementary materials included in this article.

    Supplementary Materials

    S1 File. Interview guide for current market price, number of services days and rental value.

    (DOCX)

    pone.0295388.s001.docx (17.2KB, docx)
    S2 File. The dataset.

    Which comprises equine and human populations at the zone level, the number of equids population in different production systems, equine populations by species, age and purpose, the number of equines holding rural households, market price and biomass.

    (XLSX)

    pone.0295388.s002.xlsx (77.7KB, xlsx)
    S1 Fig. The proportion of equids biomass (a) and stock monetary value (b) with total livestock biomass and stock monetary value.

    (DOCX)

    pone.0295388.s003.docx (74.9KB, docx)
    Attachment

    Submitted filename: Response to editorial comment.docx

    pone.0295388.s004.docx (22.5KB, docx)
    Attachment

    Submitted filename: Response to reviewers_2.docx

    pone.0295388.s005.docx (27.6KB, docx)

    Data Availability Statement

    All relevant data are within the paper and its Supporting information files.


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