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Tail length variation between Mezayen camel breeds. (a) Majaheem camels are characterized by long tails with a narrow tail-base. (b) Shaele, and (c) Waddah camels, which represent the Malaween breeds, display short-tails with wide tail-bases. The white disks on the tail are reference scales (five centimeters in diameter). Images were extracted from Cdrom Archive photos (collected by the authors).
Source publication
Camels are livestock that exhibit unique morphological, biochemical, and behavioral traits, which arose by natural and artificial selection. Investigating the molecular basis of camel traits has been limited by: (1) the absence of a comprehensive record of morphological trait variation (e.g., diseases) and the associated mode of inheritance, (2) th...
Citations
... Suri alpacas are known to have straight smooth and lustrous hair and Huacaya alpacas have crimped and fluffy hair (McGregor, 2012). Likewise, the dromedary camel (a member of the camelid family) exhibits distinct variation in hair properties, such as length, shape, diameter, and color (Alhaddad et al., 2019). Hair shape in dromedary camels have been recently classified into five categories each with distinct properties (Akbar et al., 2024). ...
... The current study utilized camel tail-hair follicles as the source of DNA. A total of 102 camels were selected for this study from the camel biobank and phenotype archive at Kuwait University (Cdrom Archive) (Alhaddad et al., 2019). The camels represented six show ('Mezayen') camel-types of the Arabian Peninsula, along with Omani and Pakistani camels. ...
... This gene has not been studied for its effect on hair in any camelid species, despite many exhibiting hair shape variations. Dromedary camels exhibit distinct variation in hair shape, with curly hair being often preferred among breeders (Alhaddad et al., 2019). Thus, investigating the genetic basis of hair shape would assist camel breeders in designing selective breeding programs targeting curly hair. ...
... In conservation and/or breeding programs, two essential data registries are crucial: phenotypic records of the traits of interest and genealogical information [5]. Estimating individual breeding values using phenotypic and pedigree information is limited for camels due to the lack of traditional pedigrees [6,7]. To overcome this technical constraint and enhance genetic advancement, efforts are being made to reduce generation intervals [8], which can be achieved by implementing genomics-based selection programs. ...
In the realm of animal breeding for sustainability, domestic camels have traditionally been valued for their milk and meat production. However, key aspects such as zoometrics, biomechanics, and behavior have often been overlooked in terms of their genetic foundations. Recognizing this gap, the present study perfomed genome-wide association analyses to identify genetic markers associated with zoometrics-, biomechanics-, and behavior-related traits in dromedary camels (Camelus dromedarius). 16 and 108 genetic markers were significantly associated (q < 0.05) at genome and chromosome-wide levels of significance, respectively, with zoometrics- (width, length, and perimeter/girth), biomechanics- (acceleration, displacement, spatial position, and velocity), and behavior-related traits (general cognition, intelligence, and Intelligence Quotient (IQ)) in dromedaries. In most association loci, the nearest protein-coding genes are linkedto neurodevelopmental and sensory disorders. This suggests that genetic variations related to neural development and sensory perception play crucial roles in shaping a dromedary camel’s physical characteristics and behavior. In summary, this research advances our understanding of the genomic basis of essential traits in dromedary camels. Identifying specific genetic markers associated with zoometrics, biomechanics, and behavior provides valuable insights into camel domestication. Moreover, the links between these traits and genes related to neurodevelopmental and sensory disorders highlight the broader implications of domestication and modern selection on the health and welfare of dromedary camels. This knowledge could guide future breeding strategies, fostering a more holistic approach to camel husbandry and ensuring the sustainability of these animals in diverse agricultural contexts.
... There are six color classes: black (Majaheem), smokybrown (Sofor), brown (Shaele), red (Homor), wheat (Shageh), and white (Waddah) [40,41]. Several subtypes within each breed correspond to subtle differences in coat color and tone [42,43]. ...
Background
Hair characterization is critical for determining animal individuality throughout life. This study aimed to assess the morphological features of dromedary camel hair in relation to age.
Materials and methods
Hair samples were obtained from the camel humps of 30 dromedary camels separated into three groups: G1 (n:10) aged one-year, G2 (n:10) aged 3–5 years, and G3 (n:10) at the age of 8–10 years. The hair was examined using light microscopy, SEM, and SEM-EDX.
Results
The Maghrebi camel had varied medulla patterns and structures across the ages. In the G1 group 75% had continuous medulla patterns and amorphous medulla structures, compared to 70% in G2, and 90% in G3. The medulla index increased with age, rising from 0.3 to 0.77%. The shaft width grew in size from G1 to G2, then fell to approximately one-third of the G2 size at G3. The cortex and cuticle widths were also determined by age, and they increased in the G1 compared to G3 camels. The shape of the cuticle scales in G1 camels was wavy, like mountain tops with irregular edges, within G2 camels the scales were particularly long, oval-shaped scales with smooth, wavy borders. The scales of the older G3 camels were quite long and rectangular. SEM-EDX spectra recognized carbon, oxygen, nitrogen, sulfur, calcium, aluminum, silicon, and potassium at the medulla and cortex. Sulfur levels were highest in the G2 samples but lowest in the G1 samples.
Conclusion
The dromedary camel’s hair structure and mineral content, particularly carbon and nitrogen, differed as camels aged.
... This finding is likely influenced by the particularly homogeneous higher length and larger thickness of fibers in this body area of the studied camel breed (Fernández de Sierra and Fabelo Marrero 2017). From a genomics perspective, this unique characteristic could be further confirmed based on the research by Alhaddad and Alhajeri (2019), who identified that variations in FGF5 gene are associated with hair length variability in dromedary camels. ...
The variability of camel hair fibers physical-mechanical properties across sampling body areas and phaneroptics continue to be relatively unexplored topics in scientific literature. With the aim to valorize camel hair fibers, the present investigation has examined, through discriminant canonical analysis, fiber properties of Canarian camel hair regarding the body region sampled by comparing them with Merino sheep wool, world’s most demanded textile fiber. Additionally, camel hair attribute differences depending on phaneroptics such as coat or eye color and particularities have been determined. Diameter at the base of the fiber is higher for adult camels and increases from the mid-region to the back of the animal. Besides, the highest variability in both staple length and mean diameter was found for camel shoulder and hump fibers. Camel tail dock was the region with the finest fibers but also the one accounting for the highest percentage of residual dirt. Coat color and particularities were unlikely to significantly (p < .05) affect fiber diameter and strength but did affect the brightness of final textile products. These results may help to tailor strategies within camel farming systems seeking the maximization of their productive outcomes, which is of utter relevance in endangered animal genetic resources.
... Among livestock species, camels are notably overlooked in breed characterisation based on morphometric assessment, despite the well-established correlation between body morphology and productive function . The literature on phenotypic and genotypic variability in camel species for morphometric traits is significantly less extensive compared to other livestock (Babelhadj et al. 2017;Alhaddad and Alhajeri 2019;Alhajeri et al. 2019). However, there is a positive trend in camel demographics and geographical distribution (Faye 2022), accompanied by growing socio-economic interest in their production as sustainable species . ...
Extant diversity for phenotypic traits is an essential criterion to be considered when ordering priorities for conservation and improvement of animal genetic resources. Concretely, the characterisation of the distinctive body morphometry of a particular group of animals can aid in the design of selective breeding programs, given the strong correlation between body morphology and productive function. The present research aims to characterise an endangered autochthonous camel breed (Canarian camel), mainly relegated to leisure riding, for its body morphology, with a double objective: to explore the phenotypic diversity and structure of the breed for zoometric traits and assess the zoometric profile of this genetic resource that supports its differentiation from other camel breeds. Overall, the results highlight the existence of a high degree of diversity, which may be linked to genetic factors for zoometric traits in an endangered autochthonous breed with traditional in situ breeding schemes, which predicts the success of the implementation of genetic improvement schemes for such functional characteristics. This phenotypic diversity in body morphology could also be a tool for the evaluation of new functional niches within the efforts of functional valorisation of this camel breed for its sustainable conservation. Body morphology traits in the studied camel breed are significantly influenced by sex, physiological status and coat colour.
... To investigate the genetic basis of the adaptation of camel RBCs, and likely WBCs, to aridity, a phenotyping protocol of the RBCs' response (de)hydration needs to be established. This can then be used to phenotypically screen different camels and conduct candidate gene sequencing, association, or whole genome sequencing studies [25]. Here, our objectives are to (1) examine the changes in the area (a proxy for volume) of camel blood cells (RBCs and WBCs) in response to solutions with decreasing concentrations of NaCl solutions, and to (2) identify the conditions (NaCl concentration and incubation time) under which these blood cells, especially RBCs, can be phenotyped in a large population in an efficient manner. ...
... Three healthy adult half-sibling female camels (Cdrom 239, 243, 245, Shaele camel-type [25]), raised under identical environmental conditions, diet, and access to water were selected as blood sample sources. During routine veterinary examination, whole-blood samples (6 ml) were withdrawn from their jugular veins directly into sterile EDTA tubes, which were then inverted 2-3 times, placed on an ice box for transportation, and then stored in 4ºC for~24 hours. ...
Single-humped camels are livestock of physical, physiological, and biochemical adaptations to hot desert environments and to water scarcity. The tolerance of camels to water deprivation and their exceptional capacity for rapid rehydration requires blood cells with membranes of specialized organization and chemical composition. The objectives of this study are to examine the changes in the area (a proxy for volume) of camel blood cells in solutions with decreasing concentrations of NaCl and consequently identify the conditions under which blood cells can be phenotyped in a large population. Whole-blood samples from three healthy adult female camels were treated with four different concentrations of NaCl and examined at six incubation-periods. Observationally, red blood cells in all treatments remained intact and maintained their elliptical shape while white blood cells experienced some damage, lysing at concentrations below 0.90%. Average basal (in 0.90% NaCl) RBC area was ~15 μm² and swelled in the various treatments, in some cases reaching twice its original size. Excluding the damaged cells, the average area of combined WBCs, ~32.7 μm², expanded approximately three times its original size. We find that camel WBCs, like their RBCs, are adapted to hypotonic environments, and are capable of expanding while maintaining their structural integrity.
... Camels have a considerable role in the lifestyle of various societies, particularly those in dry zones in the Middle East and the Arabian territory (Kaskous, 2016). Camels exhibit unique morphological, biochemical, and behavioral traits, which arose from natural and artificial selection (Alhaddad and Alhajeri, 2019;AlAskar et al., 2020;Alaqeely et al., 2021). Approximately, 29 million camels are distributed all over the world, 95% of them are dromedaries (Sikkema et al., 2019). ...
Background
Camels are subjected to a wide variety of nutritional deficiencies as they are largely dependent upon grazing desert plants. As a consequence, the syndrome of pica or depraved appetite is occasionally seen in dromedary camels. The condition is manifested as chewing or eating abnormal things such as wood, dirt, bones, stones, clothes, plastics, mud, sand, or other inanimate objects.
Aim
This study was designed to investigate the clinical, ultrasonographic, and postmortem findings in dromedary camels with pica or depraved appetite.
Methods
Twenty-five camels of 5 days to 15 years were examined. Owner complaints included depraved appetite, loss of body condition, regurgitation of stomach content, and partial or complete absence of feces. Symptoms described were present for a period varying between 3 days, up to 12 months. The stomach compartments and small and large intestines were scanned using ultrasonography from the right and left sides of the abdomen. Necropsy was carried out on six female and three male camels where the thoracic and abdominal organs were examined with special attention to the digestive system.
Results
The affected animals had a history of gradual loss of body conditions, eating foreign objects, decreased or total absence of feces, and regurgitation of stomach content. Using ultrasound, the foreign body was imaged occluding completely or partially the intestines. Foreign bodies within the rumen could not be visualized with ultrasound. In cases where the rumen is impacted by sand, small pin-points revealing acoustic enhancement were imaged. Foreign bodies were removed from the rumen at exploratory rumenotomy (n = 11), laparotomy (n = 3), or at necropsy (n = 8) in the form of plastics, cloths, sand, mud, wool balls, robes, glasses, or even metallic objects which may be blunt or sharp. Sixteen (64%) of the camels were recovered while the remaining 9 (36%) did not survive.
Conclusion
The syndrome of pica or depraved appetite is an important condition in dromedary resulting in the ingestion of objects other than normal feed. Substantial economic losses are expected as a result of this syndrome. Ultrasonography of the digestive system may help the clinician in some cases to localize of occluding foreign bodies in the intestines, while in the transabdominal scanning of the stomach is valuable only in cases of sand impaction.
... Therefore, Alaskar et al. (2021) [26] favor careful examination of the separate breeds prior to selection of specific populations for breeding/production programs and for genetic studies. Nowadays, this happens using, among others, the principles of the CD-ROM archive [27]. The late breeding age (~4 years), and the long gestation (~13 months) and weaning (~9 months) [4] as well as the pastoralist/extensive production system have prevented breeders from accurately recording the improvement of their breeds in studbooks, unlike breeders of other domesticated animals with much shorter breeding age, gestation and weaning times [27,28]. ...
... Nowadays, this happens using, among others, the principles of the CD-ROM archive [27]. The late breeding age (~4 years), and the long gestation (~13 months) and weaning (~9 months) [4] as well as the pastoralist/extensive production system have prevented breeders from accurately recording the improvement of their breeds in studbooks, unlike breeders of other domesticated animals with much shorter breeding age, gestation and weaning times [27,28]. ...
... Dromedaries have been kept in captivity for thousands of years and its breeding and selection has resulted in a multi-purpose animal that can be used for transport, war and as a producer of milk, meat and wool in nomadic areas and more permanent residences [23,[42][43][44][45][46]. The animal of today is also characterized by an extreme tameness [27]. ...
Being in an advanced stage of domestication is a newly proposed requirement to decide which animals can be safely kept by humans. Dutch legislators were the first to apply it and other European countries may be tempted to adopt a similar approach. Unexpectedly, the Dutch assessors considered the dromedary (Camelus dromedarius) as being insufficiently domesticated and this species will therefore no longer be able to be kept as a production animal from 2024 onwards. In a recent publication on this topic, we showed that the domestication of the dromedary is actually very advanced. In this paper, we apply the same criteria that were used by the Dutch assessors to determine the degree of domestication, taking into account the most recent scientific developments in this area, even though it should be noted that these criteria have neither been peer-reviewed, nor published in an international scientific journal. For the sake of comparison, and in order to validate the procedure, we also applied these criteria to the house cat. The results confirm that the dromedary is highly domesticated, but also that the house cat (Felis silvestris catus) is at most semi-domesticated. Obviously, we agree with the decision of the Dutch legislators to place the house cat on the positive list, but our analysis demonstrates that this was decided on false grounds. Our analysis makes it clear that the requirement of being in an advanced stage of domestication is not suitable. Instead of maintaining this requirement, we recommend implementing evidence-based, peer-reviewed methods to decide which animals can be kept by humans, and to include species specific-guidelines in the legislation on how this can be achieved safely.
... In order to address these constraints, the use of geometric morphometrics to effectively capture the overall size and shape of camels has been proposed (Rahagiyanto et al., 2019;Gherissi et al., 2022). The many advantages of geometric morphometrics (threedimensional) over the traditional method (one-dimensional) include proper account for size differences, provision of a more realistic image, easiness, less workload, and impersonal impartiality (Zelditch et al., 2012;Alhaddad and Alhajeri, 2019;Sénèque et al., 2019;Çağlı and Yılmaz, 2021;Gherissi et al., 2022). ...
Camels (Camelus dromedarius) in Africa are adapted to arid and the semi-arid environmental conditions, and are valuable for meat, milk and fiber production. On account of the growing demand for camels in this continent, there is a need for knowledge on their phenotypic and genetic diversity. This is fundamental to sustainable herd management and utilization including the design of appropriate breeding and conservation strategies. We reviewed studies on the phenotypic and genetic characterization, breeding objectives, systems of production, productive and reproductive performances, and pathways for the sustainable rearing and use of camels in Africa. The morphological and genetic diversity, productive and reproductive abilities of African camels suggest the existence of genetic variations that can be utilized for breeds/ecotypes’ genetic improvement and conservation. Possible areas of intervention include the establishment of open nucleus and community-based breeding schemes and utilization of modern reproductive technologies for the genetic improvement of milk and meat yields, sustainable management of rangelands, capacity building of the pastoralists and agro-pastoralists, institutional supports, formation of centralized conservation centres and efficient and effective marketing systems.
... The natural adaptations of the dromedaries were anthropologically exploited via (1) its domestication around 2000-3000 years B.C., (2) the expansion of their uses, and (3) the development of unique populations (i.e., camel-types) (Uerpmann and Uerpmann, 2002;Almathen et al., 2016;Orlando, 2016). However, unlike other domesticated animals (e.g., cattle, sheep, horses, dogs, and cats), dromedaries do not currently have breed definitions, standards, registries, or breeders' organizations (Arman, 2007;Lynghaug, 2009;Alhaddad and Alhajeri, 2019). Named dromedary populations are locally known and occasionally documented, but little is known about their breed status. ...
... Different dromedary camel-types have been named, yet little or no documentation can be found about their breed status (Arman, 2007;Lynghaug, 2009;Porter et al., 2016;Alhaddad and Alhajeri, 2019). Several camel-type naming systems were previously described such as those based on ecotype (e.g., hill and riverine), country (e.g., Omani and Sudani), region of origin (e.g., Raka and Turkana), tribal affiliation (e.g., Kenani and Borena), and phenotype (e.g., Waddah and Shaele) (Leese, 1927;Mburu et al., 2003;Mehta et al., 2006;Ishag et al., 2010;Mahrous et al., 2011;Porter et al., 2016;Saad et al., 2017). ...
... This is in accordance with previously reported measures of genetic variability reports (Mburu et al., 2003;Legesse et al., 2018). Dromedary camel-types named based on phenotype (e.g., Majaheem, Waddah, and Awadi) are usually selectively bred for distinctive phenotypes (e.g., coat color) (Almathen et al., 2016;Porter et al., 2016;Saad et al., 2017;Alhaddad and Alhajeri, 2019). These camels formed the most homogenous group based on haplotype; with B haplotypes being overrepresented in this group. ...
Dromedary camels are outstanding livestock that developed efficient abilities to tolerate desert conditions. Many dromedary camel-types (i.e., named populations) exist but lack defined specific breed standards, registries, and breeders’ governing organizations. The breed status of dromedary camel-types can partly be assessed by exploring mitochondrial DNA (mtDNA) variation. Accordingly, this study aimed to examine the breed status and the inter-population relationships of dromedary camel-types by analyzing sequence variation in the mtDNA control region and in three coding genes [cytochrome b, threonine, and proline tRNA, and part of the displacement loop (D-loop)] (867 bp region). Tail hair samples (n = 119) that represent six camel-types from Kuwait were collected, extracted, sequenced, and compared to other publicly available sequences (n = 853). Within the sequenced mitochondrial region, 48 polymorphic sites were identified that contributed to 82 unique haplotypes across 37 camel-types. Haplotype names and identities were updated to avoid previous discrepancies. When all sequences were combined (n = 972), a nucleotide diversity of 0.0026 and a haplotype diversity of 0.725 was observed across the dromedary-types. Two major haplogroups (A and B) were identified and the B1 haplotype was predominant and found in almost all dromedary-types whereas the A haplotypes were more abundant in African regions. Non-metric multidimensional scaling revealed an increased similarity among Arabian Peninsula “Mezayen” camel-types, despite their defining coat colors. The relationships among dromedary camel-types can partly be explained by mtDNA. Future work aimed at a deeper understanding of camel-type breed status should focus on a high number of nuclear markers.
