Breeding Practice and Correlation of Conformation Traits With Milk Offtake of Camel in Afar Region

Background: Camel are able to survive and well adapted in harsh environment and reproduce in such environment due to their unique physiology and morphology. It is also serves as source of cash income, milk, meat etc. The study was conducted in four districts of Afar Regional State with the objective of determine the breeding practice and correlation of conformation traits with milk offtake of camel. Method: Purposive random sampling were employed to select districts and target farmers. Milk offtake, body and udder conformation traits were taken from 320 she-camels. All the collected data were analyzed using Statistical Package for Social Sciences version 20.0 (SPSS, 2017) and index was computed using weight average. Result: The breeding objective of the farmers in the study area were milk, meat, wealth and social statues. Primordial traits preference for selecting breeding she-camel was based on milk yield, body size and conformation, disease resistance, fast growth and adaptation with an index value of 0.119, 0.105, 0.10, 0.096 and 0.094, respectively. Feed and recurrent drought, disease incidence, poor veterinary service, lack of modern breeding program hinders the productive performance whereas, poor feed quality, long age at rst service, calving interval, calve mortality and abortion were the major challenges for reproductive performance of she-camels. District had a signicant variation on udder and body conformation traits. The mean value of naval height, naval length, body length, foreleg length, hind leg length, pelvic length, height girth and hump circumference were 2.04±0.06, 2.46±0.06, 145±1.39, 149.24±1.30, 163.78±1.19, 25.33±0.31, 236.05±1.47and 78.51±1.06cm, respectively. The average value of milk yield, distance between fore teat, distance between rear teat, fore teat circumference, fore teat height, udder size circumference, udder size height and udder size length were 837.46±7.66, 7.92±0.36, 7.06±0.06, 6.71±0.11, 5.09±0.08, 45.13±1.34, 6.80±0.27 and 14.30±0.33cm, respectively. The correlation coecient between body conformation trait and milk offtake were signicant positively correlated with height at girth and chest length. Highest correlation coecient was obtained between milk offtake and hind teat circumference, udder size circumference and udder size length. Conclusion: It was concluded that camel had a conceivable for the multiuse role to produce income for pastoral and agro-pastoral livestock keepers.


Introduction
In the arid and semi-arid zones of the world, it is inevitable for livestock to be well adapted to the harsh environment [1]. Camels are able to survive and reproduce in such environments due to their unique morphology, physiology and serve as source of cash income, draft power, meat, milk [2] and wool since their domestication [3]. Camels are important livestock population for harsh environment in Asia and Africa and highly contribute to the pastoralists and agro-pastoralists living in the insubstantial environments [4]. seasonal mobility due to the shortage of rainfall, in the dry season; the pastoralists are forced to move their animals to far distance for water and grazing land. Camel herd movement may move the whole herd to water points and to relatively better areas where green fodder is available.

Sampling Procedure and Sample Size
Three zones (zone one, two and three) and four districts were selected purposively based on camel populations and access to transportation. From each districts, three kebeles were considered to take lactating she-camel samples for this study. In each district, 80 she-camels were also encountered to take body measurements and daily milk production. Semi-structured questionnaire was used to collect information on indigenous knowledge of pastoralists and agro pastoralists about common conformation traits used by camel holders as criterions for choosing good milk yielders of she-camels. This followed by a purposive-random sampling for data collection and on a total 160 households considered to assess current milk off-take of lactating she-camels. These she-camels were monitored and register the name of owners and camel for data collection on reproductive performance, body conformation traits and milk yielding potential. The sample household was selected based on the principle proportional to size sampling technique. The sample size required for this study was determined by the formula recommended by Arsham (2007) for survey studies as illustrated below: N = 0.25/SE 2 Where: N = Sample size SE = Standard error Hence, at 5% standard error, the total numbers of households to be selected was 100. However, to increase the precision of data collection and analysis it is scaled to 160 households.

Data Collection
Formal survey Forty households in each district was selected purposively to administer a questionnaire. The structure and semi-structured questionnaire was designed to explore general information about conformational traits used by pastoralists and agro pastoralists as indicators for milk production potential of she-camels as well as reproductive performance of camels, trait preference, breeding practices and indigenous knowledge. Group discussion was also be used to ll any emerging information gap. Four open group discussions (4-9 members) were carried out at selected sites of each district.
Collection of milk off-take data Milk off-take data was collected from each registered and identi ed she-camel on speci c investigation days. The following procedure was followed throughout: Camels that only calved at short rainy season was involved; Milk sample collection and recording was started two weeks after calving as camel rst milk (colostrums) is not palatable Calf suckling was also be allowed for 15 seconds to stimulate milk let down To the degree that possible milking continued until the udder was considered empty to ensure complete milking; Volume of milk off-take from every milking session was measured by a given graduated cylinder and recorded in a given format Milk off-take was recorded every three days for twelve consecutive weeks in case of Agro pastoralists and for every another day for two weeks duration in pastoralist camel owners because of their mobility Trained enumerators from the villages were used to milking, record data under supervision, and follow up.

Measuring and observing of conformation traits
Quantitative and qualitative data She-camels selected for milk off-take recording was used to collect data for quantitative traits (body and udder conformation traits). The body conformation traits recorded was navel ap height and length, body length, hind and fore leg length, pelvic height, pelvic length, height at wither, height girth, chest length, hump factor, hump circumference. The udder conformation traits was also recorded like milk yield, difference between fore teat, difference between rear teat, fore teat circumference, fore teat height, hind teat height, hind teat circumference, udder size circumference, udder size height and udder size length as described in detail by [13] in cross breed dairy cows. Quantitative measurements were made on 320 (two she-camel per household) mature she-camels and 80 lactating she camels per each sampled districts.

Data Management and Analysis
The primary and secondary data collected from each site was recorded in a standard format and feed into the computer using Microsoft Excel (2007) for further analysis. Collected data was entered into Statistical Package for Social Sciences version 20.0 (SPSS, 2017) for analysis.

Questionnaire data
Data collected through questionaries' was described by descriptive statistics using Statistical Package for Social Sciences version 20.0 (SPSS, 2017). Ranking analysis was under taken for data on conformation traits as related to selection of camels like selection criterions of camel, sources of breeding bulls and trait preferences. In the preference ranking method, index was computed using weighed averages and indexes was ranked using auto ranking with MS-Excel 2007.The following formula was used to compute index as employed by Musa et al. [14]: Index = R n * C 1 + R n−1 * C 2 …. + R 1 * C n / ∑(R n *C 1 + R n−1 * C 2 + …. +R 1 *C n ) the rst rank Measureable data Each of the quantitative traits (milk yield and conformation traits) as well as correlations (relationship) between milk off-take and measured conformation traits was described by descriptive statistics using Statistical Package for Social Sciences version 20.0 (SPSS, 2017). The model to analyze milk yield and udder/ body measurements was: Yi = µ + Ei + ei where Yi = the observed J (milk yield, udder and body conformation trait) in the i th districts µ = overall mean Ei = the effect of i th Districts (i = Chifra, Abeala, Dubti and Gewane) ei = random residual error 3. Result

Herd composition
The herd composition of camel in the study area is presented in Table 1. The average herd structure of lactated she-camel was higher in Chifra and Dubti districts when compared to the remaining two districts. Camel herd structure in female calves less than 1.5 to three years were more intended to keep by producers than male calves across all districts. This is due to farmers mostly kept few males for breeding purpose based on their family history performances and body conformation traits. Extra males are served for ritual ceremonies in wedding, special religious holy days, meat sale and as source of income by marketing the live camels. Males were castrated to control undesired breeding when they approach to maturity, for meat purpose and draught power utilization. As stated in Table 1, the herd composition of dry she-camel, pregnant she-camel and young camel heifer's greater than 1.5 to three years was higher in the Dubti than the other three districts. According to the respondents of camel producer's she-camels can kept in the presence of abundant pasture feeds for about 40 years for the sake of milk harvesting in its lifespan for home consumption and surrounding communities during de cit. Those long years are considered if animals are no longer constrained with poor reproduction and milk production performances. Availability of feed for animals in the area is another factor to be kept she camels in its herd for several years. However, during the milk collection, the maximum year of she-camels in the production system was 36 years ( Table 2).
The average reproductive performance of camel in the study area is presented in Table 2. The average age at maturity, age at calving, number of calves per she-camel and age of she-camel was higher in Chifra districts when compared to Abeala, Dubti and Gewane. Age at rst service and age at calving results as assessed in the study was different across Chifra with the other three district; it may be attributed to the fact that the she-camels attain maturity later in the Chifra areas when compared to those reared in the three districts, which may be effect of both genetic and non-genetic factors.
According to the respondents, she-camels remains productive for about 40 years in the presence of abundant pasture feeds for the sake of milk production to home consumption and surrounding communities during de cit. Availability of feed for animals in the area is another factor to be kept she camels in its herd for several years. However, during the milk collection the maximum year of she camels in the production system was 36 years.
The calving intervals of she-camel is one of the most important factors affecting the lifetime productivity of camel. The average calving intervals of she-camel was greater in Gewane and Dubti when compared Chifra and Abeala districts. This may be due to better accessibility in feed and water than the two districts. Based on the respondents, the calving interval of she-camels is increasing over time due to various constraints prevailing in several years because of climate change and weather variability's in the lowland areas.  (Table 2). Low calf crop production per she-camel was obtained in Abeala and Gewane districts than Chifra and Dubti. This may be in uenced by variations due to overall management practices and other environmental factors such as chronic feed shortage and frequent drought occurrences.

Breeding practice and trait preference of camel
The source of camel breeding bull as practiced in the study area is presented in Table 3. About 89 percent of the respondents in this study revealed that more selection focus on the selection of breeding bulls than dams since they perceive a single bull could serve more females and provide hundreds of improved traits of offspring throughout its lifetime than its counterparts. The main source of breeding bull in the study area was home breed bull, neighboring bull, common bull and purchased bull with an index value of 0.27, 0.22, 0.18 and 0.14, respectively.
The breeding objectives of the farmers in the study districts were milk, meat, wealth, and social status, culture and insurances in the order of importance in the communities, respectively (Fig. 1). However; whenever farmers of both production systems are with the availability of no choice to use the rst, second and third priorities of bulls for mating; mean a while they enforced to use either donated or unknown bulls for mating with no clear family history of the breeding bull. The primarily criteria pertaining in trait selection or preferences of the camel in the study area is presented in Table 4. The primordial trait preference for selection of breeding camel was based on milk yield, body size and conformation, disease and parasite resistance, fast growth and adaptation with an index value of 0.119, 0.105, 0.10, 0.096 and 0.094, respectively.
Breeding e ciency, offspring quality, short calving interval, longevity, temperament and attractive color were some of the unique quality traits of these camel breeds perceived by the farmers.

Challenges of productive and reproductive performance of camel
The main reasons (as indicated by the respondents in Table 5) limited for camel production performance in the study area were inadequate feed and recurrent drought, disease incidence, poor veterinary service, travelling long distance to search for feed and water and lack of modern breeding program with an index value of 0.20, 0.19, 0.16, 0.15 and 0.14, respectively. The major challenges of reproductive performance of camel was poor feed, long calving interval, long age at rst service, poor veterinary service, calf mortality and abortion with an index value of 0.17, 0.17, 0.16, 0.15, 0.12 and 0.12, respectively.   Tables 7 and 8 indicates that, there is no variation in the body BCT of chest length, navel length and milk yield. The variation of BCT of camel within the four districts might be due to quality and quantity of feed and management level. The naval height in Abeala (1.60) was shorter as compared to the naval height of Dubti (2.55) and Chefra, 2.03). Body length was signi cantly (P < 0.05) higher in Dubti districts than the other three districts. Body length, fore leg length and hind leg length of she-camel in Dubti were signi cantly (p < 0.05) higher compared to the three districts.

Effect of districts on milk yield and udder conformation traits (UCT)
The effect of districts on milk yield and udder conformation traits (UCT) are presented in Table 8. The overall mean of milk yield, distance between fore teat, distance between rear teat, fore teat circumference, fore teat height, hind teat circumference, udder size circumference, udder size height and udder size height was 837, 7.92, 7.06, 6.71, 5.09, 6.77, 45.13, 6.80 and 14.30, respectively. Milk yield and UCT of camel were affected by district and the average milk yield in Chefra, Gewane and Abeala was higher than Dubti. The distance between fore and rear teat, udder size circumference and udder size height was signi cantly (P < 0.05) higher in Chefra district when compared to the other three districts. This may be due to the in uence of the management level of the camel husbandry practices. The distance between rear teats in Dubti was higher than the distance of rear teat in Gewane and fore teat circumference in Abeala was signi cantly (P < 0.05) higher compared to other districts. Higher milk yield was obtained in Chefra than Dubti, Gewane and Abeala districts but not signi cant. Fore teat circumference and fore teat height were higher signi cantly (P < 0.05) Abeala, than Chefra districts and hind teat height was not revealed signi cant variation across all districts. Udder size circumference and udder size length were signi cantly (P < 0.05) higher in Chefera than Gewane and Abeala districts.   MY-milk yield, DFT-distance b/n fore teat, DRT-distance b/n rear teat, FTC-fore teat circumference, FTH-fore teat height, HTC-hind teat circumference, HTH-hind teat height, USC-udder size circumference, USH-udder size height, USL-udder size length, a, b, c, means with the different superscripts across column's are signi cant at (P < 0.05), L -liter 3.7. Phenotypic correlation between milk yield and body conformation traits of camel The phenotypic correlation coe cients between milk yield and body conformation traits within districts are presented in Table 9. Chest girth was positively correlated with milk off-take in Chefra, Dubti and Gewane (r = 0.455, 0.529 and 0.526, P < 0.01), respectively, but Abeala was positively correlated but nonsigni cant. However, in Gewane districts hump circumference, hump factor, height at wither, foreleg length, hind leg length, pelvic height was positively correlated with milk off take, and this is not signi cant but low and negative (Chefra) and positive (Dubti and Abeala) correlated with milk yield. Generally, body conformation traits (height at girth and chest length) positively correlated with milk off-take, and the best measure for she-camels of all districts.

Phenotypic correlation between milk yield and under conformation traits
The association of milk off-take with distance between fore teat in Chefra, Dubti, and Gewane camel shows positive and signi cant correlation (r = 0.392, 0.273, and 0.334 P < 0.05), respectively (Table 10). However, correlations between milk off-take and distance between fore teat in Abeala was positive correlated but not signi cant. Generally, the phenotypic correlation between milk yield and udder size length, udder size circumference and hind teat circumference was positively correlated in all districts. Udder size height was positively correlated in Chefra, Abeala and Gewane with milk yield or off take nonetheless negative correlated in Dubti and not signi cant in all districts.

Discussion
Reproductive performance The productive and reproductive performance of camel can be affected by several factors like inadequate feed, incidence of disease, occurrence of drought and poor veterinary service. This is in line with [6,9]. The primordial trait preference for selection of breeding she-camel were based on milk yield, which is ranked rst. This is in line with the report of Yosef et al. [9]. Body size and conformation, disease and parasite resistance, fast growth and adaptation-preferred traits followed milk yield. According to the report of Yosef et al.
[9] adaptability, breeding e ciency, growth, ability to give birth to more female and draught capacity ranked as second, third, fourth and fth followed milk production.
In the current study, the major challenge or bottleneck of productive and reproductive performance of shecamel in afar region are presented in

Milk yield and under conformation traits
There was an excessive source of variation in milk yield and udder conformation traits of she-camel (

Conclusion
The primary breeding objective of pastoral and agro-pastoral camel keepers in the study area is milk, meat, wealth and social status and cultural value of the society. The achievements of the breeding objectives of camel producers were generally poor due to the lack of institutional support and uncontrolled environmental factors. Hence, pastoralists and agro pastoralists consider majority of mental recording genealogy and body conformation trait to select camel for reproduction, production performances and replacement stock strategies in the absence of no available choice of breeding program in this harsh environments.
Majority of the respondents in this study revealed that more selection focus on the selection of breeding bulls than dams since they perceive a single bull could serve more females and provide hundreds of improved traits of offspring throughout its lifetime than its counterparts. The major challenges of reproductive performance of camel was poor feed, long calving interval, long age at rst service, poor veterinary service, calf mortality and abortion with an index value of 0.17, 0.17, 0.16, 0.15, 0.12 and 0.12, respectively.
Districts had a signi cant (p < 0.05) effect or variation on milk yield, body conformation trait and udder conformation trait. Statistically phenotypic relationships occur between milk yield, some udder conformation, and body conformation traits in all districts signi cantly and shows low to moderate correlations. Therefore, it recommended that further on station evaluation of the performance of Afar camel breed should be carried out to estimate the heritability's of conformation traits, phenotypic and genetic correlations with milk yield, to recipe standard decision-making criterions for indigenous shecamel and selection criteria for breeding camel for its future prospects.

Declarations
Authors' contributions BH is the principal researcher, prepared interview schedule to collect data, analysis and prepared this manuscript. AH, MG, SG and ST have prepared schedule, collect data while FH have analyze data, writing up article and guided BH. They helped for BH in data entry, analysis, revised manuscript minutely with critical comments and suggestions and drafted the manuscript. All authors read and approved the nal manuscript. (2010); 22(10). Figure 1 Breeding objectives of farmers in the production system Figure 1 Breeding objectives of farmers in the production system Figure 1 Breeding objectives of farmers in the production system