Musa et al. Almutairi et al. There are few studies in the literature on factors influencing the GL of camels. According to Almutairi et al.
The age of the camel and the sex of the calf had no effect on GL. Earlier, Sharma and Vyas similarly demonstrated the effect of the month of calving in Bikaner camels and also confirmed the effect of the sire on GL. Based on data from the previous sources, Al Eknah concluded that the GL of dromedary camels is mostly affected by the age of the camel at pregnancy Novoa, , the sex of the calf Agarwal et al.
They have demonstrated that environmental and physiological factors had the strongest relative effect No information was found in the literature on the genetic parameters, heritability h 2 of GL and breeding value BV of the animals based on this trait in dromedary camels. However, for other species, such as cattle or horses, a small number of sources have reported data on the heritability of this trait Table 1. In cattle, Bourdon and Brinks , Wray et al.
In the equine species, Valera et al. Christmann et al. The present study is a continuation of our earlier work Bene et al. Due to the similarity between the database and methods used, some details of the Materials and Methods described in our previous publication will not be repeated here.
During this period, a total of 58 male bull and 2, female dam dromedaries were included into the breeding programme and 4, calves progeny were delivered on the farm Table 2.
Further details on farm management have been described previously Nagy et al. Data were included only for deliveries between and days of gestation range 76 days , and outliers below and above this range were excluded from the analysis. The gestation length trait was considered as a character of the calf, since during this time the calf is developing in the uterus. While constructing the pedigree model, the paternal and maternal origins of calves were used.
Thus, the studied and presented breeding value data are referred to the sire of calves. The effects on the manifestation of the GL were interpreted as follows: Direct effect : the inherited growth and development length of the calf in the uterus. The inheritance of growth comes from the sire and the dam in half. Maternal permanent environmental effect PE : the uterus is an environment for the calf. Therefore, the maternal environment effect is the sum of the effects that the uterus, as an environment, has on the developing progeny e.
The Kolmogorov—Smirnov test was used to check the normal distribution of the GL in the database. The details of the three models are summarised in Table 3. Models used for the estimation of genetic parameters for the gestation length trait in dromedary camels.
The examined fix environmental factors for all models were as follows: ecotype of dam, parities of dam, breeding season, month of mating, and the sex of the calf Van Vleck et al. Covariant was not included into the models. To determine the most suitable model for estimating the parameters, the e 2 values and log-likelihood values —2 log L for the three different models were compared Bouwman et al.
The breeding value of the dromedary sires for the GL trait was estimated with all three models. The RPD was defined as the difference of the mean value of the GL data of close relatives progeny, sibs and half-sibs of a particular dromedary sire and the mean value of the GL data of the contemporary calf group.
Variance, covariance, correlation, heritability and breeding values according to the above-mentioned three models were evaluated as described by Willham , Trus and Wilton and Lee et al. The descriptive statistics of GL are shown in Table 4. The mean GL of dromedary camels was There was considerable difference in the magnitude of the maternal heritability between the two BLUP models. When permanent maternal environmental effects PE were not included in the model BLUP1 , the maternal heritability h 2 m value was 0.
Direct heritability h 2 d still exceeded maternal heritability h 2 m more than twice. The correlation r dm estimated between direct and maternal genetic effects seemed to be negative and quite loose —0. In addition, because the SE values were too high in the BLUP1 model, the r dm values were not reliable and informative. The c 2 value estimated by the BLUP2 model is fairly high 0. Breeding values for direct genetic effects estimated by the GLM model were generally lower than the values obtained by the BLUP models.
However, these differences did not influence the ranking of the sires by their BV. Notable differences from —8. Because the h 2 m value was very low especially for the BLUP2 model , the BV for maternal genetic effects was much lower for direct genetic effects, and no considerable differences were found among male dromedaries. The average GL of camels in our study was slightly higher than the mean that had been reported in the literature Ram et al.
As compared to other large domestic animal species, the GL of dromedary camels was much longer than that of cattle Hansen et al. According to the e 2 and —2 log L data Alves et al. As the BLUP2 model differentiates between maternal genetic and maternal environmental effects, it seems to be more appropriate for estimating genetic parameters and BV based on GL in this species.
The results of this study for direct heritability values of the GL of dromedary camels could not be compared to previous data, because no relevant information has been found in the literature. As compare to other species Table 1 , the direct heritability of GL in dromedary camels corresponds to the results of Bourdon and Brinks , Wray et al. In contrast, some authors Langlois and Blouin, ; Christmann et al. Like the previous parameter, the maternal heritability of GL of dromedary camels was closer to that seen in cattle Hansen et al.
In contrast, Christmann et al. The c 2 value of GL of dromedary camels was similar to the finding of Valera et al.
Differently from our present results, Lee et al. The relationship between direct and maternal genetic effects r dm on GL shows a tendency similar to the results of Rodrigues et al.
However, most other studies in cattle on the GL trait Crews, , the weaning weight trait Iwaisaki et al. In this study, the genetic parameters of GL of dromedary camels were partially different from those published for BW of camels previously Bene et al.
In case of GL the h 2 d was higher, the h 2 m was lower and the c 2 was slightly lower that those observed for the BW of camels. The total heritability of GL was considerably higher than that observed for BW.
This means that the effect of environmental factors was lower in the case of GL than in the case of BW. In addition, the maternal permanent environmental effect on GL and BW in dromedary camels was rather high, which again draws attention to the important role played by environmental factors.
According to the work of Heck et al. In such species the direct heritability of GL showed medium or high values for the low variability. This means that, contrary to our expectations, the variability of this trait was narrower than expected. So, the heritability of GL of camels in our study was medium. Based on these findings, our initial hypothesis was partially confirmed.
On the one hand, the direct heritability of GL was slightly higher and the maternal heritability of GL was lower than expected. On the other hand, the effect of environmental factors, based on previous results, especially those for the c 2 , was in line with the expectations. Genetic parameters for the evaluated trait advanced our understanding of the interaction between genetic and environmental effects. To the best of our knowledge, BV estimates for any trait have not been published for the dromedary camel until now, with the exception of our previous work.
The result that dromedary sires could be ranked according to their direct and maternal genetic effects, gave us the possibility to choose the sire most appropriate from this point of view to produce the next generation of dromedaries.
All in all, the results obtained in this study provide new information that can help breeding programmes and sire selection in this species. We are also grateful to the staff of the company for monitoring deliveries, care of newborn camels and collection of data.
The publication is supported by the EFOP Abdallah , H. Agarwal , S. Theriogenology 28 , — Al-Bisher , B. Al Eknah , M. Almutairi , S. Health Prod. Alves , K. Bene , Sz. Boldman , K. A set of programs to obtain estimates of variances and covariances. Bos , H. Bourdon , R. J Anim.
Bouwman , A. Carnier , P. Christmann , A. Crews , D. Cubas , A. Elias , E. Ewert , M. Goyache , F. Hansen , M. Harvey , W. Haywood , L. Equine Vet. Heck , L. Henderson , C. Biometrics 31 , — Iwaisaki , H.
Langlois , B. Lee , C. Metha , V. Indian Vet. Meyer , K. Version 3. User Notes. Mujibi , F. Musa , E. Acta Vet. Beograd 26 , 63 — Like Arabian camels, Bactrians rarely sweat, helping them conserve fluids for long periods of time.
In winter, plants may yield enough moisture to sustain a camel without water for several weeks. When camels do refill, however, they soak up water like a sponge. A very thirsty animal can drink 30 gallons of water in only 13 minutes. Like Arabian camels, Bactrians' nostrils close to keep sand at bay, and their bushy eyebrows and two rows of long eyelashes protect their eyes. Big, flat footpads help them navigate the rough rocky terrain and shifting desert sands without sinking under their own massive bulk or the weight of heavy packs.
The only truly wild camels that still exist are Bactrian camels. These herds survive in the Gobi Desert of Mongolia and China. All rights reserved. Common Name: Bactrian Camel. Scientific Name: Camelus bactrianus.
Type: Mammals. Diet: Herbivore. Group Name: Flock, caravan. Size: Over 7 feet tall at the hump. Weight: 1, pounds. Size relative to a 6-ft man:. Critically endangered. Least Concern Extinct. Current Population Trend: Decreasing. Share Tweet Email. Go Further. Animals Climate change is shrinking many Amazonian birds. Animals Wild Cities This wild African cat has adapted to life in a big city.
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