CHARACTERISTIC FEATURES, GENETIC FIVERSITY AND DUSBANDRY PRACTICES OF ETHIOPIAN CAMEL (CAMELUS DROMEDARIES)

Abstract

The objectives of this study include identification and characterization of indigenous camel ecotypes, study of the distribution and features of camel populations and husbandry practices, assessment of camel population dynamics and the genetic diversities and population structure of camel populations of Ethiopia. The study location were Jijiga, Liben, Gode and Shinille from Somali and Amibara and Mille from Afar national regional states, which represents the major camel rearing areas. The results show that camels from Gode (Gelleb) were significantly (p<0.05) superior for morphological variables particularly height at shoulder, chest depth, chest width and hip width to other camel populations examined. Average barrel and heart girths of Liben camel population were significantly (p<0.05) larger than the remaining camel populations. Females of Amibara camel population recorded significantly (p<0.05) lower values for traits mentioned above as compared to other camel populations. Quantitative and qualitative studies indicated that Jijiga and Hoor (Gode) camels are milk type whereas Liben and Gelleb camels are meat type. The principal component analysis showed that body height traits and body height together with body shape traits explained most of the shared variability in female and male camel populations, respectively. For the study of genetic diversities and population structure of camel, blood samples were collected from 114 camels belonging to six populations (17-24 per population) and DNA was extracted and genotyped using10 camel microsatellite marker loci. The results revealed the presence of high genetic diversities within Ethiopian camel populations with average observed, expected heterozygosity, total number of alleles (TNA), Mean Number of Alleles(MNA) and effective number of alleles of 0.55, 0.73,153, 6.8 (0.36), 4.47(0.23), respectively. Of the 52 private alleles in the six Ethiopian camel populations, 31 of them were occurring at a frequency of ≥5%. Most of the variation in Ethiopian camels is attributed to within population variation (92%) while only 8% was explained by between populations’ xvi variations. The between population differentiation (FST=0.105(0.01) indicate moderate population differentiation in Ethiopian camel populations. All the model and tests indicated the occurrence of genetic bottleneck (P<0.05) in Jijiga camel population in the recent past. Genetic diversity study based on mtDNA markers was carried out to investigate mitochondrial DNA (mtDNA) genetic diversity of the seven morphologically identified Ethiopian camel populations (Amibara, Mille, Shinille, Jijiga, Gelleb, Hoor and Liben). We also used DNA from the tissue of five different camel populations, namely Arabian Peninsula (Oman and Yemen), Punt land, Sudan and Egypt. We also retrieved 8 in-group (Camelus dromedaries) and 9 out-group (Camelus bacterianus and Lamma Glama) previously published mtDNA partial D-loop sequences from the GenBank (8 in-group from Saudi Arabia, 9 out-group (Bacterian) from Chinese and 1 out-group from South America camel populations) to trace the matrilineal genetic origin of camel populations. Genetic relationships and other diversity parameters in these populations were inferred from 59 randomly selected mtDNA D-loop sequences sequenced for 559 base pairs (bp). The result indicated that camel populations from the Arabian Peninsula, Saudi Arabia, East Africa (Ethiopia, Sudan and Puntland) and Egypt have average numbers of haplotypes, haplotype diversity and nucleotide diversities of 13, 0.68±0.13 and 0.0023±0.002, respectively. This implies the low genetic differentiation among camel populations in the study area. Among all camel populations studied Oman and Ethiopia (Shinille, Amibara and Hoor) have equal and the highest haplotype diversity (1± 0.11), nucleotide diversity (0.00359±0.001), and average number of nucleotide differences (2).The lowest haplotype diversity, nucleotide and average number of nucleotide difference were observed in Liben (0.33±0.13, 0.00060±0.003 and 0.33, respectively). All the DNA polymorphism shows that camels in Ethiopia have high mtDNA variation. The founder haplotype (C2) and the second largest haplotype (C4) in frequency were largely found in camels of the Horn of African origin (Ethiopia and Puntland). Likewise, camels of this region have high mtDNA variability and sequence polymorphism and therefore the ancestral camel D-Loop might have been from that region of continental Africa. All the activities related to camel rearing for different purpose (milk, meat and draft) and their distinct features in different pastoral communities may indicate that camel keeping in Ethiopia has been many centuries old traditions. Moreover, the camel paintings, fossils in different rock shelters and xvii the high genetic diversity indicates that Ethiopia is one of the origins of camel domestication. The result of the study of husbandry and breeding practices of camel show that female camel populations with age of >1(greater than one) year represents 78-83 % of the total camel herd in all the study districts. Higher number of female animals in the herd in the arid environment means providing continuous supply of milk and allowing a rapid recovery of herd numbers after a disease outbreak or drought occurrence. This shows that pastoralists breeding objectives might have been associated with the arid environmental hazards and female population in the herd. Most of the pastoral communities use single breeding male camel per 40-50 female camels and this will affect productivity and heterogeneity of camel population. With regard to trait preference, all pastoral communities ranked milk yield as the first trait of choice, except Moyale district in which adaptation trait was the primary preference. In camel and cattle population dynamics study, all interviewed pastoralists in Jijiga, Mille and Borena Districts have a plan to reduce cattle number in the herd in the future. Most of the interviewed pastoralist in Gode, Liben, Shinille and Mille Districts favor reduction of cattle number in the herd. This shows that pastoralists realize the extraordinary properties of camel to withstand the climatic stresses much better and able to provide much more milk than cattle. In general, the results showed that cattle population is decreasing from time to time, while camel population show increasing trend in arid and semi-arid areas as a result of the combined effects of pastoralist needs and the impact of climate change, which could position the indigenous cattle breed at risk in the near future. Regarding issues related to women empowerment in the study areas, there has been a variation in decision making particularly on the issues like intensity of production, breeding, camel herding, milking, marketing and other related activities. In general, this study observed that men have a dominant role in most decision making processes particularly in revenue generating activities