Quantitative and Qualitative Analysis of Hair-fibre Attributes in Four Indian Dromedary Camel (Camelus dromedarius) Breeds

Indian dromedary camels have long been a part of Indian heritage and culture, with the evidence of domestication dating back to as early as the Harappan period. However, the network of motorable roads even in the remotest location as well as the widespread agricultural mechanization has rendered these beasts of burden without much utility for farmers. Loss of grazing lands to development projects is a critical set back to the pastoral system in camel rearing. The Indian dromedary camels capable of thriving and yielding high-quality products such as meat, milk and fibers. The camel wool is luxury textile product, from the undercoat and crucial desert adaptation (Hasi et al., 2020). Camel wool has superior over cashmere, sheep, angora and alpaca wool in terms of softness, texture, warmth, durability, sustainability, water repellent and hypoallergic properties (Iglesias Pastrana et al., 2024). Hair fiber associated KRTAP7 and KAP6.1 genes were indicated diverse inhabitation (Bharathesree et al., 2019; Yadav et al., 2024).
       
Camel hair, a specialty hair fiber, possess two distinct types of hair: an outer protective coat layer of coarse guard hair and a fine insulating undercoat known as down. The fibers are collected by shearing or pulling or gathering the fallen clumps during molting in late spring or early summer (Franck 2001). Notable variations in camel fibers have been observed among different flocks and individual animals along with the same animal of different areas. Efforts are underway to evolve various chemical treatments aimed at boosting the production of high-quality camel hair products. The eco-friendly nature of camel wool enables it to be suitable for stitching the durable, sustainable and ethical fashion clothes (Agamy et al., 2024; Xiao et al., 2016). Limited studies have been carried out to evaluate the quality parameters of camel hairs globally. Therefore, the present study was conducted to explore the qualitative and quantitative characteristics of Indian Dromedary camel fibers based on the gender, breed, coat colour and different age groups to strategize the specific market demands for textiles, rugs, coats, blanket and other products.

Source of information
 
Data collected from ICAR-NRCC, Bikaner spanning six consecutive years (2018-2023), from four breeds viz. Bikaneri (520), Jaisalmeri (373), Kachchhi (419) and Mewari (402) making a total of 1714 Indian Dromedary camels (Camelus dromedarius).
 
Hair-fibre attributes
 
Annual clipping weights for quantitative analysis with fibre diameter and medullation (%) for qualitative analysis. The hair-fibre showed varying distribution, density (higher at hump), colour and quality based on animal’s body (Fig 1). Weight was measured using digital weighing balance and kept in a polythene bag after proper skirting (removal of dust and other vegetable matters). The qualitative analysis was done at TMTC division of ICAR-CSWRI, Avikanagar.


       
Descriptive statistics estimated from the standardized and classified data by R software v.4.2.0 (R core team, 2022). The least square means and effect of various factors were estimated by General Linear model (SPSS v.22, 2013).

Statistical model:
 

Y_ijklmno = µ + C_i + B_j + S_k + A_l + S_hm + Y_n + Interaction effect + e_ijklmno

 
Y_ijklmno = Observation of oth animal.
µ = Overall mean.

C_i, B_j, S_k, A_l, S_hm and Y_n = Effect of ith coat colour (i=1,2,3,4,5,6,7). jth breed (j=1,2, 3, 4), kth sex (k=1,2), lth age (l=1-5 for wool weight; l=1-4 for wool quality), mth shearing (m=1,2,3,4) and nth Year (n=1-6 for wool weight; n=1,2 for wool quality) respectively; YB, YC, YS, YA and YSh-interaction of year with breed, coat colour, sex, age and shearing, respectively;
e_ijklmno = Random error, N (0, σ²e).
       
The Bayesian analysis was performed with repeatability model using BLUPF90 (Misztal et al., 2002) to estimate (co) variance, heritability, repeatability and correlation with the pedigreed camels (Table 1). Data renumbered using RENUMF90, followed by estimation using GIBBS1F90 and POSTGIBBSF90. The desired distribution attained by 99,900 Gibbs samples (10,00000 rounds, 1,000 burn-in and 10 thinning interval) and visualized by trace plot and histogram.


 
Repeatability model
 
The model considered all fixed (breed, sex, coat colour, age group, year and shearing) and random (animal) effects.
 

Y = Xβ+Zµ+Wp+e

 
Y, β, µ and p = Vector of observed traits, fixed effects, additive genetic random effects and random animal permanent environmental effects, respectively.
X, Z and W = Incidence matrix of fixed effects, additive genetic effects and permanent environmental effects, respectively. e = Random error, N (0, σ²e).

Descriptive statistic
 
Medullation hairy and hair fibre weight were least varying and most varying trait, respectively (Table 2).


 
Quantitative and qualitative analysis
 
Effect of factors were indicated on hair-fibre weight in different years of shearing and on fibre diameter and medullation% in two years (Table 3, 4, 5, 6). The overall wool weight was highest in Bikaneri breed, red black coat- coloured animals, females and 4-6 years of age. All factors were significantly affecting the overall hair-fibre quantity and fibre diameter. The significant effect of sex and shearing numbers on overall medullation hetero; for shearing numbers on overall medullation hairy and of age group on total medullation was noticed.








 
Bayesian approach using animal model
 
The univariate analysis indicates higher residual and permanent environmental variance for Bikaneri breed (Table 7). In trace plot iterations are on X-axis and variance on Y-axis (Fig 2, 3, 4 and 5). Negative correlation was also noticed for hair fibre attributes (Table 8).












       
The high genetic potential of hair yield and fibre diameter were in accordance with Bhakat et al. (2002), Sahani et al. (1996 and 1998). The superior production in male camel is under hormonal influences. The high yield in adult camel is due to larger body size, higher hair density, nutrition and management. The year wise comparison indicates different feeding and managemental practices which are beneficial for selection decision making. Average fibre diameter (28.273±6.043 µ to 48.190±3.278 µ) ranging higher than (27.22 µ-31.45 µ) reported by Yadav et al. (2000) and in sheep (26 µ-38 µ) by Gupta et al. (1989).
       
The normalization of estimates indicated by constant trace plot (convergence) and bell-shaped histogram. The low to higher heritability as 0.07 (Bai et al., 2006), 0.10 (Zhou et al., 2002), 0.16 (Jinquan et al., 2001) 0.26 (Gifford et al., 1990), 0.29 (Pattie and Restall, 1989), 0.33 (Rose et al., 1992) and 0.71 (Bishop and Russel, 1996) were reported for Cashmere fiber. Higher additive genetic variance, heritability and repeatability in Kachchhi breed are considerable in selection decision making (Yadav et al., 2022; 2023a; 2023b).
               
The mean fibre diameter and medullation (%) revealed blending camel hair-fibre with natural or synthetic fibres. The herbal feed additives are helpful in economic improvement of hair fibre (Mejia-Delgadillo et al., 2021). The negative correlation was in accordance with blanket and carpet fibres while positive correlation was similar to yarn in Chokla and Merino wool (Gupta et al., 1998). The breed wise and coat colour wise correlated response to selection can be achieved. 

Our work provides the phenotypic and genetic significance of hair production traits. The studied traits have several futuristic benefits viz. simple and easily demonstrable from a mere distance, used to manufacture the economically sustainable and organic textile product. The variations in fibre color and quality are important to capture diverse textile market and preparation of blends camel hair fibre to produce superior fabrics. The significant effect of factors on hair fibre attributes and correlation signify further improvement by selection which can be combined with fibroblast growth associated genes in future.

There is no conflict of interest to the proposed work.