Carcass characteristics and economic analysis of supplementing powdered coffee leaves to indigenous Wolaita highland sheep diets based on hay

Abstract

Sheep production in Ethiopia is an important activity for smallholder farmers, but the sector has been challenged by many factors among which feed shortage is the major one. To solve this challenge, farmers traditionally supplement sheep with coffee leaf. This study was conducted at Areka Agricultural Research Center, Wolaita zone, Southern Ethiopia, with the objectives of evaluating carcass yield, composition and economic profitability of supplementing powdered coffee leaves to indigenous Wolaita highland sheep fed hay-based diets. This experiment followed the layout of Completely Randomized Design (CRD) on twenty male intact sheep with mean initial body weight 17.4 ± 0.1 kg and five treatments. Treatments were T1, T2, T3, T4, and T5 with powdered coffee leave meal inclusion (CLPMI) proportion of 0, 5, 10, 15, and 20%, respectively with four replications per treatment. Concentrate mix (CM) of 300 gm on dry matter base/head/day was provided for the lambs. The trial was conducted for 90 days followed by digestibility trial of 7 days. Significant difference (P < 0.05) was observed among treatments on slaughter body weight, empty body weight, hot carcass weight and dressing percentage. On partial budget analysis, 20% of coffee leaves powder meal inclusion resulted in optimum DM intakes, weight gain and carcass yield. Higher net income (959.5ETB (17.26USD)/sheep) was obtained from the sheep supplemented with 20% inclusions (T5) of coffee leaves powder meal followed by T4 (15% powder coffee leaves meal inclusion), T3 (10%), T2 (5%) and T1 (0%). Thus, this study highlighted a positive potential of coffee leaves powder meal as a supplement to poor quality roughages.

Keywords:

• carcass characteristics
• economic analysis
• coffee leaf meal
• indigenous Wolaita highland sheep

1. Introduction

Sheep rearing is one of the main cash income sources for the farmers in Ethiopia. Feed shortage in terms of quality and quantity is one of the major bottlenecks facing small holder sheep producers in Ethiopia in general and in the current study site specifically (Mohammed, 2020). Farmers use different strategies traditionally to supplement sheep during feed scarcity and complement their productivity throughout the year. In the current study site it is common to use coffee leave in the form of liquid or powder to supplement the growing lambs and fattening rams to improve productivity. No research has been done prior to this on effect of supplementing coffee leave powder meal on carcass characteristics and economic feasibility on Wolaita highland sheep in the current study area. Thus, this study is aimed at evaluating dietary effects of coffee leaves powder meal supplementation on carcass characteristics and economic feasibility of intact male yearling indigenous Wolaita highland sheep fed hay as basal diet.

Sheep production of Ethiopia is characterized by low output in terms of growth rate, meat production and reproductive performance (Adugna et al., 2000). The causes for low productivity of sheep are multidimensional that include poor genetic potential, poor veterinary services, inadequate quantity and quality of feed, and poor breeding strategy (Betsha, 2005). Among these limiting factors, poor feed supply and feeding system is the most important as the feed resources in different parts of Ethiopia are generally natural pasture and residues of different crops (Adugna et al., 2012). The stability of natural pasture as a source of feed is, however, limited to the wet season (Zinash et al., 1995). Most of it is depleted and degraded because of overgrazing (Alemayehu, 2016).

Ethiopia is the center of origin for highland coffee (Coffee Arabica L), which is one of the most cherished cash crops in the country (ECFF Environment and Coffee Forest Forum, 2015). Coffee is intercropped with other buddy crops or multipurpose fodder trees in complex agro forestry systems as low-cost production options to spread food and cash security (Taye, 2014). Almost every type of plant that is produced or processed for human food or animal feed yields one or more by-products that can be utilized as feed for animals (Ensminger, 2002). Thus, coffee production for human consumption gives rise to a number of byproducts that may be used as ruminant feeds. These include leaves, pulp from the bean, coffee residues, coffee meal and spent coffee grounds (Bouafou et al., 2011). Coffee leaves are relished by sheep and have a high nutritive value with high amount of primary nutrients (Nitrogen (47%), Phosphorus (61%), and Potassium (36%) and secondary essential minerals (Calcium (50%), Magnesium (47%), and Sulfur (33%) (Michiel et al., 2004). In the current study area, coffee leaf drink locally called (tukkiya-tochiya) and a drink made from the infusion of coffee leaves locally called (haytta-tukkiya) are common feed supplements for livestock especially small ruminants and lactating cows for many years. People traditionally believe that, supplementing coffee leave meal as feed additive to animals improves feed intake, growth rate, milk yield and milk quality and carcass characteristics. However no scientific research has been conducted on its effect on carcass characteristics and economic analysis of its supplementation and has never been supported by any scientific literatures.

In this context, this work aims to evaluate dietary effects of coffee leaves powder meal supplementation on carcass characteristics of intact male yearling indigenous Wolaita highland sheep fed hay as basal diet, as well as to analyze economic feasibility of supplementing coffee leaves powder meal in intact male yearling indigenous Wolaita highland sheep.

2. Materials and methods

2.1. Experimental design and treatments

The experiment was conducted at Areka Agricultural Research Center, Mante Dubo sub-research site, Ethiopia. The site is located at a distance of about 309 km south of the capital of Ethiopia, Addis Ababa and at an altitude of 1711 masl and situated at N 07’ 06.4312` and E037’ 41.688`. The mean annual temperature of the area was between 22°C and 24°C. The rain falls between 1201 and 1600 mm with highest from July to September.

In the experiment, which lasted for 90 days, 20 male sheep with an average initial body weight of 17.39 ± 0.094 kg were used. The experimental design was a completely randomized design with five treatment diets that corresponded to five levels of coffee leaves powder meal supplementation in the proportion of 0.0, 5.0, 10.0, 15.0 and 20.0% in the daily requirement of concentrate mix with four replications per treatment (Table 1). Four sheep were randomly assigned to each of the five treatments. They were allowed to an adaptation period of 2 weeks to the environment and experimental diets. At the end of the adaptation period the sheep were fasted overnight and initial body weight was measured.

Table 1. Treatment layouts of the experiment

Treatments	Concentrate mix (g/kg DM)	Coffee leaves powder meal supplement (% of 300 g/kg DM)	Pure water and natural pasture hay
T1	300	0	Ad libitum
T2	300	5	Ad libitum
T3	300	10	Ad libitum
T4	300	15	Ad libitum
T5	300	20	Ad libitum

2.2. Experimental diet preparation and feeding

Natural pasture was harvested manually from Areka Agricultural Research Center, Mante Dubo sub-research site at November 2021, kept under hay shade to maintain its quality and used as a basal diet thought out the experimental period. During feeding, hay was chopped (Figure 1) to a length of approximately 5–10 cm for ease of feeding. Appropriate matured and green coffee leaves (test feed), were collected by hand stripping and were subjected to air drying under shade for 3–5 days by spreading on plastic sheets. Air dried coffee leaves were chopped by using local mortar to powder form to pass through sieve to get a uniform texture. Processed coffee leaves powder meal was kept in clean sacs thought out the experimental period.

Figure 1. Experimental feed preparation.

Taro (Boloso-I), a common root crop supplemented commonly to animals in the area as concentrate source was purchased from the neighboring farmers of the study area and it was washed, trimmed, chopped and sun dried for 3–4 consecutive days by thinly spreading on plastic sheets to reduce moisture content and make easy to grind. The chopped and sun dried taro was milled by using milling machine. Wheat bran was purchased from Areka Town administration, TAM flour mill factory. Nuge seed cake and mineral mixture were purchased from Bahir Dar city, Amhara Region State. Finally, the concentrate supplement feed was prepared from Taro Boloso-I, Wheat bran, Nuge seed cake and mineral mixture, which were mixed in the ratio of 45, 29.97, 15.03 and 10%, respectively by using mixing machine. Processed concentrate mix was kept in clean sacs thought out the experimental period. The CP was set based on the recommendation made by Ensminger (2002), who suggested that for moderate growing lambs that weigh 10 to 20 kg body weight, the CP required for supplement would range from 16.3 to 26.4%. The amount of concentrate mixture in this experiment was determined to be 300 g on DM basis based on the recommendations of Zemichael and Solomon (2009) for Arado sheep (Table 2). Pure drinking water and natural grass hay were supplied ad libitum for sheep. The concentrate feed was provided twice a day at morning and afternoon in the ratio of 50:50.

Table 2. Composition of concentrate feed in the rations

Concentrate mix	Percentage	Amount g/kg DM
Taro Boloso-I	45	135
Wheat bran	29.97	89.91
Nuge seed cake	15.03	45.09
Mineral mixture	10	30
Total	100	300

2.3. Experimental animals and their management

The age of sheep was estimated based on dentition and information obtained from the owners. Before starting the experiment, the sheep were ear tagged and de-wormed against internal parasites (Figure 2) with Albendazole 300 mg and Acaridae for external parasite.Thereafter, they were housed individually in pens prepared for sheep experiment in the Areka research center. Body weights of the sheep were recorded at the beginning of the experiment and after 2 weeks by using a hanging scale of 100 kg capacity.

Figure 2. Experimental animals and their management.

2.4. Data collection

2.4.1. Evaluation of carcass and non-carcass parameters

At the end of the digestibility trial, all of the experimental animals were fasted overnight; two sheep from each treatment group were selected on weight base, taken to a slaughtering slab. On slaughtering, the sheep were killed by severing the jugular vein and the carotid artery with a knife. The blood was drained into bucket and its weight was recorded. The skin was carefully flayed to prevent fat and tissue attachments. The skin was weighed with ears and immediately after the removal of legs below the fetlock joints. The gastrointestinal tract with the exception of the esophagus was removed with its contents and weighed. The gastrointestinal organs were reweighed after emptying its contents. Fat in gastro-intestinal tract and kidney fat were removed and individually weighed. Internal organs, namely, lung, trachea, esophagus, heart, liver, kidney and pancreas, were removed and weighed.

The hot carcass weight (HCW) was estimated after removing weight of the head, thorax, abdominal and pelvic cavity contents as well as legs below the hock and knee joints and was measured after about one hour from slaughter. Next, the rib eye muscle area was obtained by exposing the longisimuss dorssi muscle after a transverse section on the carcass between the 12^th and 13^th ribs, and the rib eye muscle area was traced first on a transparent paper then by counting the number of squares lying on the traced picture in the square paper and multiplied by the area of Single Square (Müller, 1980). The empty body weight was calculated as gut content deducted from slaughter weight. Percentage of total edible offal components (EOC) were taken as the sum of, heart, liver, empty gut, kidney, tail fat and tongue. Percentage of total non- edible offal (NEOC) component were taken as the sum of blood, head except tongue, skin with ears, esophagus,lung, abdominal fat, kidney fat penis, testis, testicle fat, trachea, spleen, gallbladder without bile, pancreas, feet and gut content. Classification of offal’s into NEOC and EOC were based on eating habit of the people residing in and around the study area. Dressing percentage was calculated as weight of carcass divided by either slaughter weight or empty body weight multiplied by 100 according to the procedures of Bonvillani et al. (2010). The dressing percentage is therefore based on:

$\begin{array}{rl}& \mathrm{\%}\mathrm{S}\mathrm{l}\mathrm{a}\mathrm{u}\mathrm{g}\mathrm{h}\mathrm{t}\mathrm{e}\mathrm{r}\mathrm{w}\mathrm{e}\mathrm{i}\mathrm{g}\mathrm{h}\mathrm{t}\mathrm{b}\mathrm{a}\mathrm{s}\mathrm{i}\mathrm{s}\left(\mathrm{S}\mathrm{W}\right)=\frac{Hotcarcassweight\left(kg\right)}{Slaughterweight\left(kg\right)}\times 100\\ & \mathrm{\%}\mathrm{E}\mathrm{m}\mathrm{p}\mathrm{t}\mathrm{y}\mathrm{b}\mathrm{o}\mathrm{d}\mathrm{y}\mathrm{w}\mathrm{e}\mathrm{i}\mathrm{g}\mathrm{h}\mathrm{t}\mathrm{b}\mathrm{a}\mathrm{s}\mathrm{i}\mathrm{s}\left(\mathrm{E}\mathrm{B}\mathrm{W}\right)\hspace{0.17em}=\frac{Hotcarcassweight\left(kg\right)}{Emptybodyweight\left(kg\right)}\times 100\end{array}$

2.4.2. Partial budget analysis

The partial budget analysis was taken to determine cost benefit (profitability) analysis of supplementing different proportions of coffee leaf powder meal inclusion on sheep feed. The variable costs were calculated from test feed (coffee leaf powder meal), concentrate mix feed, basal feed, sheep and medication costs which are supplied for each experimental treatment costs. The partial budget analysis was calculated from the variable costs and benefits. At the end of the experiment, the selling price of each experimental sheep was estimated by three experienced sheep dealers from Areka Town market and the average of those three-estimation prices was taken. The total returns (TR) were determined by calculating the difference between the estimated selling prices and purchasing price of experimental male intact indigenous Wolaita Highland sheep. Net return (NR) was calculated as:

$\mathrm{N}\mathrm{R}=\mathrm{T}\mathrm{R}-\mathrm{T}\mathrm{V}\mathrm{C}$

The change in net return (ΔNR) was calculated as the difference between change in total return (ΔTR) and the change in total variable costs (ΔTVC).

$\mathrm{\Delta }\mathrm{N}\mathrm{R}=\mathrm{\Delta }\mathrm{T}\mathrm{R}-\mathrm{\Delta }\mathrm{T}\mathrm{V}\mathrm{C}$

2.5. Statistical analysis

All data collected were analyzed by ANOVA using the general linear model procedures of statistical analysis system (SAS, 2002). Means were compared with the Tukey test and considered statistically significant at a P < 0.05.

$\mathrm{Y}\mathrm{i}\mathrm{j}=\mu ++{\mathrm{T}}_{\mathrm{i}}+\mathrm{E}\mathrm{i}\mathrm{j}$

Where:

• Y_ij = Overall response variable;

• μ = Overall mean;

• T_i = Treatment effect (i^th effect of coffee leave powder meal supplementation);

• E_ij = Random error.

3. Results

3.1. Carcass and non-carcass characteristics of experimental animals

3.1.1. Carcass characteristics of male intact indigenous Wolaita highland sheep

The result showed that significant difference (P < 0.05) was observed among treatments on slaughter body weight, empty body weight, hot carcass weight and dressing percentage (Table 3). Slaughter body weight, empty body weight, hot carcass weight and rib eye area were statistically higher (P < 0.001) in sheep received T5 than the remaining treatments. Whereas, the dressing percentage values (both in slaughter and empty body weight base) were statistically higher in T2 compared to others.

Table 3. Carcass components of male intact indigenous Wolaita highland sheep supplemented different level of coffee leaves powder meal

Variables	T1	T2	T3	T4	T5	SEM	p-value
Slaughter weight (kg)	20.0^c	20.3^c	23.1^b	24.2^b	26.8^a	0.19	<0.0001
Empty body weight (kg)	15.1^c	15.7^c	18.7^b	19.2^b	22.4^a	0.17	<0.0001
Hot carcass weight (kg)	6.1^e	7.0^d	7.2^c	7.5^b	8.8^a	0.05	<0.0001
Dressing percentage
Slaughter weight based	30.6^c	34.3^a	31.3^bc	31.3^bc	32.9^ab	0.36	<0.001
Empty body weight based	40.5^b	44.5^a	38.7^b	38.8^b	39.4^b	0.49	<0.001
Rib eye Area (cm^2)	8.7^d	9.0^d	9.81^c	10.4^b	11.6^a	0.12	<.0001

^a-e= means with different superscripts within a row are significantly different (p<0.05); SEM= Standard error of mean.

3.1.2. Non-carcass components characteristics

The heart, liver and kidney contents in this study ranged from 313.6 (T1) to 492 g (T5), 72 (T1) to 179.6 g (T5), 65.3 (T1) to 108.6 g (T5), respectively. Tongue weight of sheep in T4 and T5 was statistically higher (P < 0.001), than sheep in T1 and T2 (Table 4). Besides, the gut empty and tail fat contents in the current result ranged from 451.7 g (T3) to 671 (T2) and from 203 g (T1) to 501 g (T5), respectively. The highest (P < 0.05) kidney weight was observed for the sheep in the T5. In the present study, tail fat appeared to be lower for (T1) compared to others.

Table 4. Edible non-carcass components of male intact indigenous Wolaita highland sheep supplemented with coffee leaves powder meal

ENCC (g)	T1	T2	T3	T4	T5	SEM	p-value
Heart	314^e	391^d	417^c	431^b	492^a	0.54	<0.0001
Liver	72.0^e	101^d	88.5^c	123^b	179.6^a	2.0	<0.0001
Kidney	65.3^d	70.0^cd	76.0^c	92^b	108.6^a	1.80	<0.0001
Tongue	69.0^c	74.0^c	82.0^b	94^a	101^a	1.31	<0.0001
Gut empty	662^b	671^a	452^e	558^d	634^c	1.58	<0.0001
Tail fat	203^d	219^d	340^c	437^b	501^a	11.3	<0.0001

^a,b,c= means with different superscripts within a row are significantly different (p<0.05); ENCC= edible none carcass components; SEM= Standard error of man.

There were significant differences (P < 0.05) among treatments in weight parameters of non-edible offal components (Table 5). The head (i), blood (j), testis, gall bladder (without bile, feet spleen and lung, gut contents, kidney fat and abdominal fat were ranged from 1.03 (T2) to 1.2T2) to 994 g (T4), 176 (T1) to 233 g (T5), 19(T2) to 24 g (T5), 413 (T1) to 550 g (T5),40 (T1) to79.6 g (T5) and 134(T2) to 246 g(T5), 12 (T1) to 57.3 g (T4) and 17 (T1) to 65 g (T5), respectively. The gut content of the study was statistically lower (p < 0.05) for sheep in T5, but not statistically different (P > 0.05) among other treatments. Except for blood and gut contents, most of the non-edible offal in the current study were statistically higher (P < 0.05) for coffee leaves powder meal supplemented sheep than the control.

Table 5. Non-edible non-carcass components of male intact Wolaita highland sheep supplemented with coffee leaves powder meal

Carcass components	T1	T2	T3	T4	T5	SEM	P-value
Head (kg)	1.08^b	1.03^b	1.10^b	1.13^b	1.30^a	0.03	<0.01
Blood(g)	817^c	779^d	948^b	994^a	983^a	4.04	<0.0001
Gut content (kg)	5.03^a	4.7^ab	4.4^ab	5.0^ab	4.3^b	0.14	<0.01
Skin (kg)	2.07	2.07	2.3	2.0	2.5	0.07	0.006
Tests(g)	176^e	187^d	208^c	226^b	233^a	1.05	<.0001
Bladder with no tongue	19.6^b	19.0^b	21.3^ab	22.7^a	24.0^a	0.60	<0.01
Feet(g)	413^d	428^c	441^c	476^b	550^a	2.98	<0.001
Spleen(g)	40^e	52^d	62^c	70^b	79.6^a	1.09	<0.0001
Lung(g)	156^c	134^d	226^b	157^c	246^a	1.51	<0.0001
Kidney fat	12.0^d	17.7^c	19.7^c	57.3^a	30.7^b	0.83	<0.0001
Abdominal fat	17.0^e	24.0^d	31.0^c	61^b	65^a	0.58	<0.0001

^a,b,c= means with different superscripts within a row are significantly different (p<0.05); SEM= Standard error of man.

3.2. Partial budget analysis

The result indicated that higher net income (959.5ETB (17.36USD)/sheep) was obtained from the sheep in (T5) followed by T4, T3, T2 and T1 (Table 6). It was also observed that, there was no loss of money in all treatments as a result of supplementation. However, coffee leaves powder meal supplemented sheep showed positive net profit and income than control.

Table 6. Partial budget analysis of male intact indigenous Wolaita highland sheep supplemented with coffee leaves meal powder meal

Items and expenses	T1	T2	T3	T4	T5
Sheep Purchase price (ETB/head)	1050	1050	1050	1050	1050
Hay intake (kg/head)	54	54	54.0	54	54
Cost of GH (ETB)	110	110	110	110	110
Cost for Coffee leaf (ETB)	0	100	200	300	400
Concentrate mix Cost (ETB)	237.5	237.5	237.5	237.5	237.5
Medication Cost (ETB)	6.0	6.0	6.0	6.0	6.0
Total variable cost	1,403.5	1,503.5	1,603.5	1,703.5	1,803.5
Final selling price (R) (ETB)	1769	2100	2240	2430	2763
Net income change (ETB)	365.5	596.5	636.5	726.5	959.5

ETB=Ethiopian birr, 1ETB = 0.018USD

4. Discussion

Supplementation of powdered coffee leaves meal to male intact indigenous Wolaita highland sheep that fed high as a basal diet has resulted in higher Slaughter body weight, empty body weight, hot carcass weight and rib eye area than control ones. The reason for this could be associated to the differences in the final live body weights as a report of Cloete et al. (2004) found that larger final live body weight results in a higher carcass yield. Even though there was no statistical difference (P > 0.05) between the treatments in terms of dressing percentage in empty body weight basis, higher dressing percentage was recorded in T2 relatively than others which could be an indication of the effect of gut fill on dressing percentages. Gut fill constitutes a significant amount of the body weight even when the animals are fasted long hours (Gibb & Ivings, 1993). On the other hand, this is good implication for prediction of carcass weight on empty weight basis that seems to be appropriate as the influence of gut fill would be removed. The rib eye area ranged between 8.7 cm² (T1) and 11.6 cm² (T1) in current study was higher than the ranges reported by Mulu (2005) (5.20 to 8.80 cm²) for Wogera sheep, and Asnakew (2005) (5.20–8.80 cm²) for Hararghe highland goats. However, the mean rib eye area measured in this study was lower than (29.7 cm²) reported by Gebregziabher et al. (2003) for Horro lambs supplemented with different concentrate mixtures. The lower rib eye area scored in control animals for the current study indicated that, sheep supplemented with different level of powdered coffee leave meal were able to develop a better muscle than control.

Except for blood and gut contents, most of the non-edible offal in the current study were statistically higher (P < 0.05) for supplemented sheep than the control. In line with this result, Tafa et al. (2010) reported higher non-edible offal for supplemented Arsi- Bale sheep than the control group sheep fed basal diet of grass hay. In the contrary, Gebeyew et al. (2015) reported that there was no significant difference for non-edible offal among treatment diets for Hararghe Highland sheep. Differences in fat deposit is highly directly related with plane of nutrition or energy content of the diet and appropriate dietary energy-protein combinations (Archimede et al., 2008). On the other hand, the increase in liver weight with supplementation might be related to the storage of reserve substances such as glycogen as described by Lawrence and Fowler (1998). Relatively higher skin weight obtained in T5 might be associated to higher metabolizable energy intakes which has resulted in better subcutaneous layer fat deposition. According to the result of Assefu (2012), skin could be affected by diet, where high level of concentrate feeding resulted in heavier skin weight. The gut content in current study was lower (p < 0.05) for T5, but nearly the same other treatments. The higher gut content for T1 might be due to more feed retention time in the rumen and also reflected in poor digestibility which agrees with the finding of Van Soest (1994).

The higher net income was obtained in supplemented animals than control. Higher net income was recorded in T5 followed by T4, however, there was no net income and loss for T1. This indicates that there was no loss of ETB/sheep in all treatments and supplementation of coffee leaves powder meal has persuaded positive net profit and income. Similarly, Shiferaw et al. (2022) has reported that non-conventional feed supplementation is potentially more practicable and economically cheap for smallholder farmers engaged in sheep fattening in Ethiopia.

5. Conclusion

In conclusion, 20% supplementation of powdered coffee leaves meal to indigenous Wolaita highland sheep seem to be positive in terms of carcass characteristics improvement and economic efficiency. Accordingly it is more applicable and affordable for farmers in the study site. However, further study is needed by increasing level of supplementation so that higher net income and improved carcass characteristics could be obtained as it is limited in 20% of concentrate feed in current study but showed no negative impact and higher potential.

Author’s contribution

The research reported on this manuscript is related to a wider project that is focusing on analyzing feeding value and nutritional quality of powder coffee leaves meal on growth, production performance, carcass characteristics and economic efficiency of indigenous Wolaita highland sheep that fed hay as basal diet. The remaining parts will also be prepared and submitted as soon as possible for publication.

• Author 1: Participated in designing the study, data collection, analysis and manuscript writing

• Author 2: Participated in designing the study, experimental works, measuring carcass characteristics and data analysis

• Author 3: Participated in data collection, experimental works, laboratory analysis and manuscript writing

Conflict of interest

The authors declare that there is no competing interests between them and with any financial organization regarding the material discussed in the manuscript.

Acknowledgements

The authors would like to thank Wolaita zone administration for financial support and Areka research center for permission of experimental site/house for the experiment. They also would like to extend their thanks to Hawassa University and their laboratory technicians for facilitating lab works.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Tibebu Kochare

Tibebu Kochare, Wolaita sodo University, college of Agriculture, Email: [email protected]