Ethiopian Sheep Breeds’ Wool Fiber Yield and Moisture Regain Determination and Characterization

doi:10.21203/rs.3.rs-1629795/v1

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Ethiopian Sheep Breeds’ Wool Fiber Yield and Moisture Regain Determination and Characterization

https://doi.org/10.21203/rs.3.rs-1629795/v1

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published 12 Apr, 2023

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Ethiopia has indigenous breeds of sheep such as Washera, Menz, Farta and Tikur. Small scale enterprises are using the wool fibers from these breeds to produce local products such as rugs, socks, sweaters, quilts, mattresses. This study investigates four Ethiopian sheep breeds wool fiber yield and moisture regain properties. 400 total sheep, 50 males and 50 female sheep were included in the study. The results revealed that the average wool fiber yield according to IWTO CWC standard of male sheep for Washera, Menz, Farta and Tikur were 89.29%, 88.29%, 73.33%, 81.74% and for female sheep were 88.75%, 81.91%, 73.23%, 80.80% respectively. The selected Ethiopian wool fiber yield showed higher as compared to some countries sheep breeds. The study also revealed that the raw wool fiber moisture regains values for male sheep of Washera, Menz, Farta and Tikur were 10.67%, 16.91%, 11.11%, 10.71% and for female sheep were 11.92% 15.91%, 11.83%, 9.22% respectively. This shows that the Ethiopian wool fiber having good fiber yield and moisture regain can be used as a source of manufacturing different wool products.

Wool fiber

wool fiber yield

moisture

Ethiopia

sheep breed

In textile manufacturing natural fibers are mostly used due to their applications in in different areas such as in textiles, composites, handicrafts, packaging, medicine and suitability to the environment [1]. One of the natural protein fiber produced from sheep is wool with a unique physical and chemical properties such as warmness or coolness, high moisture absorption that makes it to be comfortable to wear, perceived by consumers to be renewable, ‘sustainable’ and ‘environmentally friendly’, therefore, recently consumers need and so there is demand in the market [2], and can be used as source of polymers for electrospinning [3]. Interms of fiber comfortability, due to the wool fibres’ thermal insulation property, being breathable, warmness and moisture wicking properties it is one of the most utilized animal protein fibres [4], used as raw material for apparel and textiles sector many years [5]. The leading countries in raw wool fiber production are Australia, China and New Zealand, China as major raw wool importer and also leading in manufacturing semi and finished wool products. China is the world’s leading exporter of semi and finished wool products and dominates the world wool textile industry (particularly for wool clothing), Italy (yarn and garment), India (carpet and rug), United Kingdom (garment), Germany (yarn and garment), Turkey (garment and carpet), Belgium (carpet), United States (carpet), and Bangladesh (garment) [5].

Ethiopian textile sector creates employment opportunity as well as has substantial growth by exporting textile goods and the export is projected to be $ 26 billion. Most textile industries are processing cotton fiber and some synthetic and regenerated fiber [6]. The sheep population of Ethiopia reached around 30,612,976 of which 27.82% is ram and 72.18% is ewe indigenous with quite a number of hybrid and exotic sheep broad classes which can be taken as a source of raw wool fiber for textile industries as a wise strategy to manage their natural fibers scarcity [7]. From the total population of Ethiopian sheep, about 75% are processed in small scale mixed farms [8]. Opportunity of African Growth and Opportunity Act (AGOA), that includes most Sub-Saharan African (SSA) industries duty-free and quota-free trade access gives considerable advantage for exporting textiles and apparel for the countries in the region [9], this can give advantages to Ethiopia too.

There are some investigation a bout Ethipian sheep breeds properties such as diameter, strength, fineness and length but for limited sheep breeds. Sitotaw, D.B., et al.(2018) characterized the crimp and finnenes properties of three Ethiopian wool breeds as indigenous (Menz), exotic (Dorper) and cross breed (50% Dorper/50% Menz). They found that the breed type, body parts and age of the sheep influenced the crimp and fineness properties of the wool fibers and the crossbreed wool fiber is the fineness wool fiber [7]. Sitotaw, D.B., et al.(2021), also studies about the finnenes and strngth of the four Ethiopian sheep breeds wool fiber properties and found that the strength and fineness of wool fibers have positive correlation and suitablity for many applications [10]. All studies showed that the neck parts of sheep wool fiber has good quality as compared to other parts.

The sheep sector in Ethiopia is mostly processed by traditionally via small scale and farmers have not technical knowledge as a result the productivity and their profit is low. This is because of there is no wool institutions and professional staff supporting sheep sector. Therefore, collection of wool is not systematized in many parts of Ethiopia and farmers are throwing away the sheep wool into rivers or set it on fire in open places [11].

Table 1

Some typical parameters of the wool fibres [5]
Wool fiber Parameter	Value
crystallinity (%)	47.8
Tenacity (g/Tex)	Dry	9–18
Tenacity (g/Tex)	wet	7–16
Elongation at break (%)	Dry	25–40
Elongation at break (%)	wet	25–60
Moisture regain (%)	13–18

The wool fiber may contains wool grease that creates difficulty in wool processing partially in the finishing processes to these fibres. These greasy can be removed by souring in pre-treatment processes of the wool fibres and other treatments. The commercial wool fiber values are mainly determined on the basis of the amount it yields after scouring [12]. Wool fiber yield is one of the main characteristics of wool that indicates the amount of clean wool fiber after raw wool is processed which may be expressed interms of clean mass or as a percentage of the mass of raw wool prior to processing [9, 13], a major determining factor for the value of raw wool [13]. As a result the raw wool fibers should be appropriately scoured and washed before the fiber is processed into fabrics [14].

Till now the Ethiopian wool fiber yield and moisture regain did not studied yet. Therefore, the main objective of this study is to determine and characterize the Ethiopian sheep breeds wool fiber yield, moisture regain properties in the case of Amhara National Regional State in Ethiopia. Shearing wool fibers from all sheep are taken from the neck parts.

2.1. Materials

The raw wool fiber samples were collected by shearing from different sheep breeds, four sheep breeds (Washera, Menz, Farta and Tikur) which are found in the Amhara regional state of different places. The selected sheep are of males and females and four different breeds (menz, washera, farta and tikur) are selected. A total of 400 sheep, 50 males and 50 females, from each bread type were selected in this study. Wool shearing has done from the neck parts from each breed and sex, age of ≥ 3–5 years is selected for laboratory samples. Figure 1 shows the different parts of sheep that can be taken and Fig. 2 shows some of Ethiopian sheep breed types. The non-ionic detergents and chemicals for scouring used are Eco-nonionic detergent X100, pure water. Alkali (caustic soda), sulphuric acid, nonionic detergent and coastic soda were used for removing vegetable matter. ETADRY oven dry machine was used to determine the oven dry mass of wool fiber samples. Standard conditioner was used for sample conditioning purpose. Digital electronics balance with precision of 00 was used to take the weight of samples.

2.2. Methods

2.2.1. Sampling and conditioning

Wool fiber samples are drawn by core sampling technique for testing. Core sampling produces a statistically precise sample of sufficient size for the test to perform the required tests in a laboratory. The samples are representative of the lot irrespective of the number of bales [2].

The wool fiber sample was taken from the neck part of all the sheep. The wool fibers by nature are hygroscopic and regain moisture well as a result the fiber samples must be conditioned. To get balanced moisture in the fibers after conditioning need to be reserved in dry sample bags for testing. After the samples were conditioned for 24 hours at 20 ± 1ºC temperature and 65 ± 2% relative humidity according to ASTMD1776 [15].

2.2.2. Testing and Characterizing

Scouring of Wool Fiber

Un-scoured wool is called greasy wool. The wool fiber yield was determined after all impurities are removed from the raw wool fiber [16]. Scouring of the Wool fibers is the first step in the processing of wool fibre into yarn [14]. The conditioned greasy wool fiber samples weighing about 120g from each type were scoured using a liquor ratio of 1:50, a temperature of 60◦C with 2 g/L of Eco-nonionic detergent X100. The greasy wool fibers were immersed into the scouring solution and soaked for 20 min. After soaking for 20 minutes, the greasy wool fibers were removed from the scouring bath and then pushed gently into the warm water (i.e., 60◦C) to be washed for 10 minutes, then the water was drained out. The samples were again subjected to a second scouring bath with the same liquor ratio, temperature, quantity of detergent and duration as in the first bath and soaked for 20 minutes. The samples were then rinsed with water at a temperature of 60◦C and then the rinse water was drained out and then the samples were cold washed. The wool fibers were then dried in an oven at 60◦C for 24hours, the dried scoured wool samples were then conditioned at 20 ± 2◦C, 65 ± 3% relative humidity for over 24hours and then weighed using the electronic balance to obtain their final weight. This constant dry weight is recorded for use in later calculations. After scouring there will still be residual impurities remaining in the wool and these must be measured by more sophisticated methods.

Determination of Wool Fiber Moisture Regain

Because of the wool fibers have a hygroscopic characteristic, the moisture regain of wool in particular Ethiopian wool must be characterized. Moisture regain is well-defined as the weight of water in the wool fiber expressed as a percentage of the oven dry weight of the wool fiber. The moisture regain of raw wool was determined after obtaining the weight of wool dried at 105⁰C for 20minuts on the ETADRY machine according to ASTMD1576-13 [17]. The drying temperature during testing was set to 103 ◦C. Moisture regain is calculated based on Eq. 1, where W_d is the mass of the dry specimen and W_m is the weight of the conditioned specimen.

Moisture regain of the scoured samples was tested by oven-dry testing method as specified by IWTO-33, “method for the determination of oven-dry mass and calculated invoice mass of scoured or carbonized wool by International Wool Textile Organisation”. The drying temperature during testing was set to 103^◦C and the moisture regain of the samples was obtained using Eq. 1.

$Moisture regain\%= \frac{\left(Wm -Wd\right)}{Wd} \times 100\%$ --------------------------(1)

Vegetable Matter (VM) Testing

To know the vegetable matter, 40g dry scoured wool fiber samples were dissolved in hot 10% alkali (caustic soda) solution. The alkali-insoluble impurities were then rinsed, dried and weighed and expressed as a percentage of the 40g test specimen. Wool fiber ash residue percentage was determined from the dried scoured subsamples incinerated for two hours at a temperature of 750 ◦C. The percentage of grease residue was evaluated by an alcohol extractable matter test on a Soxhlet extractor.

Carbonized Vegetable Matter Testing

The weighed, scoured and preconditioned wool sample were carbonized by using 5–7% sulfuric acid and 1–2 g/L nonionic detergent with 1:25 liquor ratio, socked for 2–3 hours at 20–30◦C and then rinsed and dried at 60◦C to a low regain, followed by baking at 100◦C to carbonize the vegetable matter. Next samples passed through heavy rollers to crush and then shaken to remove the embrittled vegetable matter. Lastly samples passed through sodium carbonate neutralizing solution, rinsed with a small addition of detergent and dried at room temperature. The samples conditioned at a standard temperature of 20 ± 2◦C and humidity of 65 ± 2% for 24 hours, the weight of the samples was recorded.

Determination of Wool Fiber Yield (Y)

The yield test was performed according to IWTO-19 which comprises removing of all impurities and moisture to get wool base percentage. Wool base is oven dry weight free from all types of impurities expressed as a percentage of the weight of the sample. In calculating the commercial wool fiber yields, wool base (WB), vegetable matter base (VMB) and hard heads base (HH) are used and standard allowances for moisture, small amounts of residual ash (dust) and alcohol extractable matter left after processing are considered. The general wool fiber yield formula calculation is based on Eq. 2 as follows:

$Wool yield = \frac{\left(WB \times (10+Regain\%\right)}{\left(100 -Ash residue and alcholextractivs)\right)}$ ------------------------------------(2)

In this study the following two formulae (ASTM and IWTO standard) were used to calculate different commercial wool fiber yields. ASTM Clean Wool Fibre Present (ASTM CWFP): uses an allowance of 13.64% regain and 2.27% ash and alcohol extractives. IWTO Clean Wool Content (IWTO CWC): uses an allowance of 2.27% residual ash and alcohol extractives and 17% regain.

$ASTM Clean Wool Fiber present = WB \times 1.1628$ ------------------------------(3)

$IWTO CWC =WB \times 1.1972$ -------------------------------------------------------------(4)

Wool Fiber Yield (Y)

Yield is defined as the weight of clean wool after all impurities are removed which can be expressed as gram or as a percentage of the greasy wool weight. It can be assessed by determining the clean wool obtained from greasy wool after removing all impurities. The various calculated commercial yields for the four Ethiopian sheep breeds are as given in Table 3. In this study, the wool fiber yield(Y) is expressed as a percentage of the raw wool and the wool base (WB%) for each sample is the percentage of clean wool after the removal of all impurities. Table 2 and Fig. 3 illustrates the wool base%, commercial yields of the different sheep breeds. From Fig. 3, the wool fiber yield of Washera sheep breed (IWTO CWC of 86.29% for male, 88.75% for female and ASTM CWFP of 86.73% for male and 86.20% for female sheep) is the highest from the other sheep breeds. The lowest wool fiber yield is found for Farta sheep breed of IWTO CWC values 73.33% for male, 73.23% for female and ASTM CWFP of 71.22% for male and 71.12% for female sheep. This lowest yield of Farta sheep breed wool fiber may support the lowest strength of Farta sheep breed wool fiber as studded by Sitotaw, D.B., A.H. Woldemariam, and A.F. Tesema (2020) [18]. The Ethiopian wool fiber yield is comparable with the wool yields of the different countries sheep breeds studied by different researchers in the last such as Western Australian fleece wool yield of 49.2% – 65% [13], wool fiber yield of Tunisian sheep breed to be in the range of 50–70% [19], Kenyan wool fiber yield from 59–68% [9], scouring yield of the Changthangi sheep value of 81.06 ± 0.94% [12], and Kashmir Valley wool fiber yield 79.41 ± 0.80% [12]. From the experimental investigation and comparisons with other studied wool breed types, the Ethiopian sheep breed wool fiber yield is higher that can attract and give attention to the textile industries especially the wool textile industries worldwide and thus the Ethiopian economy can be increased.

Table 2

commercial wool fiber yield
Breed type	Sex	Raw wool fiber weight (g)	Total impurities (g)	Wool base (WB) (%)	Commercial yields
Breed type	Sex	Raw wool fiber weight (g)	Total impurities (g)	Wool base (WB) (%)	IWTO CWC (%)	ASTM CWFP (%)
Washera	Male	120.00	30.50	74.58	89.29	86.73
Washera	Female	120.00	31.04	74.13	88.75	86.20
Menz	Male	120.00	31.50	73.75	88.29	85.76
Menz	Female	120.00	37.90	68.42	81.91	79.55
Farta	Male	120.00	46.50	61.25	73.33	71.22
Farta	Female	120.00	46.60	61.17	73.23	71.12
Tikur	Male	120.00	38.07	68.28	81.74	79.39
Tikur	Female	120.00	39.01	67.49	80.80	78.48

Wool Fiber Moisture Regain

Wool fiber is capable of absorbing more moisture than cotton [20]. The moisture regain values of the different sheep breed wool is shown in Table 3. From Fig. 4 and Table 3, the highest raw wool fiber moisture regain is for wool fiber of Menz (16.91% for male and 15.91% for female). The second higher raw wool fiber moisture regain is for Washera which is 11.83%. Farta and Tikur sheep breeds’ raw wool fiber have the lowest moisture regain which is less than or equal to 10% which is not in the standard wool fiber moisture regain value (see Table 1). After scouring the wool fiber moisture regain was increased for all types of sheep breeds’ wool fiber. The order of moisture regain in decreasing manner for the four Ethiopian sheep breeds wool fiber is Menz, Washera, Tikur and Farta.

Table 3

Raw and Scoured Wool Fiber Moisture Regains
Breed		Raw wool fiber original mass (g)	Raw wool fibers oven-dry mass (g)	Scoured wool fibers conditioned mass (g)	Scoured wool fibers oven-dry mass (g)	Raw wool moisture regain (%)	Cleaned wool moisture regain (%)
Washera	Male	25.00	23.50	16.60	15.00	6.38	10.67
Washera	Female	25.00	23.03	16.90	15.10	8.55	11.92
Menz	Male	25.00	21.90	15.90	13.60	14.16	16.91
Menz	Female	25.00	22.40	15.30	13.20	11.61	15.91
Farta	Male	25.00	23.90	12.00	10.80	4.60	11.11
Farta	Female	25.00	23.08	10.40	9.30	8.32	11.83
Tikur	Male	25.00	22.90	15.50	14.00	9.17	10.71
Tikur	Female	25.00	23.93	15.40	14.10	4.47	9.22

The Ethiopian wool fiber from four indigenous sheep breeds have been investigated. The wool fiber from the neck parts of the sheep breeds showed different yield and moisture properties. The higher wool fiber yield is from Washera sheep breed and the lowest is from Farta sheep breed. The order of wool fiber yield from the higher to the lower is Washera, Menz, Tikur and Farta. The wool fiber yield results showed higher yield as compared to some countries sheep breeds. The cleaned wool fiber moisture regains also in the range of from 9–16%. This indicates that the Ethiopian indigenous sheep breeds’ wool fiber shall be a potential source of raw material for textile industries in Ethiopia. This investigation together with other researches supports concerned institutions to have an insight to propose great projects on wool for the country to focus on the Ethiopian indigenous sheep breeds hence Ethiopian wool fiber as a source of the country economy.

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Declaration of Conflicts of interest/Competing interests

☒ The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

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Availability of data and material

All data are included in the manuscript.

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Authors' contributions

Erkihun Zelalem Liyew: Conceptualization, Methodology, Investigation, formal analysis. Biruk Fentahun Adamu: Writing the original draft article structure construction, reviewing, editing, analysing.

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Download PDF

Journal Publication

published 12 Apr, 2023

Read the published version in Tropical Animal Health and Production →

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08 Sep, 2022
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You are reading this latest preprint version

Ethiopian Sheep Breeds’ Wool Fiber Yield and Moisture Regain Determination and Characterization

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Journal Publication

Version 1

Abstract

Figures

1. Introduction

2. Materials And Methods

2.1. Materials

2.2. Methods

2.2.1. Sampling and conditioning

2.2.2. Testing and Characterizing

3. Result And Discussion

4. Conclusion

Declarations

References

Status:

Journal Publication

Version 1