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The objectives of the present study were to describe specific anatomical structures of the dromedary udder. Eighty-six dromedary udders were examined, taking morphological measurements and producing injection casts using resin, gelatin, and paraffin. The udder of the dromedaries consists of four quarters. The shape of the udders and teats varies considerably between animals and is influenced by age, breeding, and lactation status. The most frequently found udder form was the globular udder (48.8%) and the most common teat form in this study was the funnel teat (44.2%). The most common teat tip shape was a smooth or a slightly rough ring teat (61.6%). Injection casts showed a complete separation of the teat canals. There is also no communication between tributary mammary complexes. Resin injections of the glandular tissue adjacent to the teat cistern showed an extensive branching into large, medium, and small milk ducts. Frozen sections of the udder revealed complete separation of the right and left mammary complex through the Sulcus intermammarius. The teat sections showed longitudinal folds from the tip of the teat to the base of the teat. A ring fold at the transition from the Ductus papillaris to the teat cistern was present. The results of this study increase the knowledge of the anatomical structures of the dromedary udder, which may be useful for breeding a selection of dairy dromedaries.
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Extraintestinal pathogenic Escherichia coli (ExPEC) strains are capable of causing various systemic infections in both humans and animals. In this study, we isolated and characterized 30 E. coli strains from the parenchymatic organs and brains of young (<3 months of age) camel calves which died in septicemia. Six of the strains showed hypermucoviscous phenotype. Based on minimum inhibitory concentration (MIC) values, seven of the strains were potentially multidrug resistant, with two additional showing colistin resistance. Four strains showed mixed pathotypes, as they carried characteristic virulence genes for intestinal pathotypes of E. coli: three strains carried cnf1, encoding cytotoxic necrotizing factor type 1, the key virulence gene of necrotoxigenic E. coli (NTEC), and one carried eae encoding intimin, the key virulence gene of enteropathogenic E. coli (EPEC). An investigation of the integration sites of pathogenicity islands (PAIs) and the presence of prophage-related sequences showed that the strains carry diverse arrays of mobile genetic elements, which may contribute to their antimicrobial resistance and virulence patterns. Our work is the first to describe ExPEC strains from camels, and points to their veterinary pathogenic as well as zoonotic potential in this important domestic animal.
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The aim of the present study was to examine the mammary gland of dromedary camels using ultrasonography, endoscopy and radiography. These techniques are easy to perform in the field and feasible to diagnose pathological conditions of the mammary gland. Udders of 49 slaughtered and 26 adult dromedary camels submitted for necropsy were used for the examinations. Additionally, 11 lactating female dromedary camels were selected for the ultrasonographic udder examination. The transition from the milk ducts into the udder cistern, the teat cistern and the teat canals were examined in individual udders. Teat cistern length, teat end width, teat wall thickness, teat cistern width and middle cistern wall thickness were measured using ultrasonography. The measurements resulted in mean values of the teat cistern length of 37.3 mm, the teat end width of 2.0 mm, the teat wall thickness of 4.4 mm, the teat cistern width of 8.2 mm and the cistern wall thickness of 3.5 mm. The teat wall was differentiated into three layers, a hyperechoic outer layer, a hypoechoic middle layer and a hyperechoic inner layer. The mid cistern wall was hyperechoic. Endoscopic examination is an easy to perform and practicable method for examining the inner structures of the teats of dead animals; however, the feasibility has not been shown in lactating animals yet. Ring-like folds were present in the teat cistern, which protruded horizontally into the lumen. It was also possible to visualize the branchlike transition of the teat cistern into the larger milk ducts. Radiographic examination using barium sulfate contrast medium showed that the teat cistern ends in a network of initially wide but branching and narrowing milk ducts. The two teat canals and cisterns are completely independent of each other and there is no communication between the glandular tissue of the two canals and cisterns.
Assuntos
Camelus , Glândulas Mamárias Animais , Animais , Camelus/anatomia & histologia , Feminino , Glândulas Mamárias Animais/diagnóstico por imagem , Glândulas Mamárias Animais/anatomia & histologia , Endoscopia/veterinária , Endoscopia/métodos , Radiografia/veterinária , Ultrassonografia/veterinária , Ultrassonografia/métodosRESUMO
In this study, the incidence, timing and risk factors associated with abortion and perinatal mortality (PM) were described in dromedary camels under intensive management. In addition, overall pregnancy losses were also summarized and weekly risk of pregnancy wastage was determined throughout gestation. Data were collected over 11 breeding seasons from September 2006 through June 2017 at the world's largest camel dairy farm. A total of 229 abortions were observed (5.05%) out of 4533 pregnancies after 60 days (d) of gestation. Most abortions were singleton (n = 199, 86.9%), but twin abortions were also recorded in 30 cases (13.1%). Abortions showed a pronounced seasonal distribution, with a peak in August. The age category (P < 0.01), breed or ecotype of the female (P < 0.05) and bull influenced the occurrence of singleton abortions. Dromedaries with twins tended to abort earlier than those with a singleton fetus (median = 232.5 d vs. 257 d, P = 0.053). Perinatal mortality was observed in 174 cases (3.84%) out of 4533 pregnancies after 60 d of gestation. The condition included the premature birth of non-viable calves after shorter than normal gestation (330-350 d, n = 26, 14.9%), the birth of well-developed but dead calves after normal gestation length (n = 120, 69.0%) and neonates that died within 48 h after delivery (n = 28, 16.1%). The frequency distribution of PM was parallel with that of parturitions. The most important predisposing factor for PM was difficult calving. Thirty-nine percent (68 out of 174) of these losses were associated with dystocia. In addition, age category (P < 0.05) and parity of the female (P < 0.01), month of delivery (P < 0.05) and breeding season (P < 0.05) also affected the incidence of PM. The cause of 60 cases of PM (1.4% of all deliveries) could not be determined and was considered idiopathic. In conclusion, one-third of total pregnancy losses occurred during mid to late gestation. Approximately 10% of pregnancies after Day 60 failed, and 90% resulted in the birth of a live calf that survived beyond 48 h. More than half of these pregnancy losses were abortions before 330 d of gestation, and approximately 40% were classified as PM. The weekly mean risk of pregnancy loss after 100 d of gestation remained only a fraction of that observed during the first 2-3 months.
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Aborto Animal , Camelus , Animais , Feminino , Gravidez , Aborto Animal/epidemiologia , Incidência , PartoRESUMO
Gestation length (GL) data of dromedary camels were analysed for the period from 2007 to 2018. The database of the largest dairy camel herds (Dubai, United Arab Emirates) was used in this study. The data of 4,084 camels included in the assessment were classified into six ecotypes (Emirati, Emirati cross, Black, Pakistani, Saudi-Sudanese and Saudi cross). The aim of the study was to describe the heritability of GL of camels and the breeding value (BV) of sires for this trait. The genetic parameters of GL were estimated by the General Linear Model method and two Best Linear Unbiased Prediction (BLUP) animal models as well. The mean (±SE) of GL of camels was 384.3 ± 0.2 days. The direct heritability of GL (0.26 ± 0.06-0.36 ± 0.08) was higher than the maternal heritability (0.00 ± 0.05-0.13 ± 0.06) obtained. The maternal permanent environmental effect (0.15 ± 0.05) was similar to the results estimated previously in dromedary camel, but higher than the data reported by relevant sources in other species. Based on the results of this study it can be concluded that the GL of dromedary camels is a species-specific value similar to that in cattle, which is less affected by the maternal influence. Considerable differences (16 days) exist among male dromedaries in their BV for the GL trait.
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Camelus , Animais , Bovinos , Feminino , Masculino , Fenótipo , Gravidez , Emirados Árabes UnidosRESUMO
In this paper, we described the incidence of early pregnancy loss (EPL) both after natural mating and embryo transfer, evaluated risk factors, and summarized the outcome of twin pregnancies throughout gestation in dromedaries under reproductive care. Data were collected over seven breeding seasons at the world's largest camel dairy farm (study 1). In addition, we determined the timing of EPL and monitored serum progesterone (P4) concentration between Days 13-70 of gestation during one breeding season (study 2). In the first study, out of 2970 pregnancies, 507 cases (17.1%) of EPL were diagnosed with transrectal ultrasonography. The rate of EPL after natural mating and embryo transfer was 16.1% (n = 422 out of 2616) and 24.0% (n = 85 out of 354), respectively. Twin pregnancies were detected in 215 cases (7.2% of all gestations), and 57 of those (26.5%) underwent complete EPL. Almost half of the early losses (n = 243; 47.9%) occurred before 30 d of gestation. Another 43.2% (n = 219) of EPL was diagnosed during the next month, and 8.9% (n = 45) occurred after 60 d of gestation. Multivariable mixed effects logistic regression models revealed that the breeding season (year) and twin pregnancy were the most important exposure variables affecting the rate of EPL (P < 0.001). The effect of some male camels was also demonstrated while other factors, such as type of breeding, age category, month of mating, breed/ecotype and reproductive history did not prove to have a significant influence. In the second study, the overall rate of EPL was 24.5% (n = 34 of 139). There was no difference in the incidence of EPL between ET recipient (24.2%, n = 23 of 95) and mated (25%, n = 11 of 44) camels. Weekly rate of EPL ranged from 0.9% to 4.8% with a decreasing tendency, and approx. 41% of the animals (n = 14 of 34) had some ultrasonographic signs of impending EPL 1 week before the final diagnosis. Mean serum P4 concentration in camels with subsequent EPL was 5.3 ± 0.1 ng/ml compared to 5.6 ± 0.04 ng/ml in normal pregnant dromedaries. Day of gestation and future EPL influenced serum P4 levels (P < 0.001) with an interaction between the two fixed factors (P < 0.05). At the time of the final diagnosis of EPL, mean serum P4 concentration was 2.8 ± 0.44 ng/ml. Although twinning had an unfavorable prognosis with a total pregnancy loss of 36.7%, it was not entirely detrimental for the final outcome of gestation as two-thirds of twin pregnancies (n = 136 out of 212) resulted in the birth of a live calf.
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Aborto Animal , Camelus , Aborto Animal/epidemiologia , Animais , Transferência Embrionária/veterinária , Feminino , Incidência , Masculino , Parto , GravidezRESUMO
Orthohepevirus A genotype 7 is a novel zoonotic variant of hepatitis E virus. To clarify infection in the animal reservoir, we virologically monitored 11 dromedary dam-calf pairs. All calves became infected during the first 6 months of life and cleared the virus after an average of 2 months. Dams did not become infected.
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Vírus da Hepatite E , Hepatite E , Animais , Camelus , Bovinos , Genótipo , Hepatite E/epidemiologia , Hepatite E/veterinária , Vírus da Hepatite E/genética , Cinética , RNA , Emirados Árabes Unidos/epidemiologiaRESUMO
Birth weight data of dromedary calves from the database of one of the world's largest dairy herds (Dubai, UAE) were analyzed for the period from 2007 to 2018. The assessment included the data of 4124 camel calves that were classified into six ecotypes (Emirate, Emirate crossed, Black, Pakistanian, Saudi-Sudanian, and Saudi crossed). The aim of the study was to describe the heritability of birth weight of calves and the breeding value of sires. Genetic parameters of birth weight were estimated by ANOVA model and two BLUP animal models as well. The mean value of the camel calves' birth weight was 34.75 ± 5.67 kg. The direct heritability of birth weight (h2d = 0.09 ± 0.04-0.11 ± 0.03) was rather low, so was the maternal heritability (h2m = 0.23 ± 0.10-0.50 ± 0.06). The maternal effect from environmental origin (c2 = 0.23 ± 0.08) far exceeded the results previously calculated in cattle. There was no difference in reliability between BLUP1 and BLUP2 models, and both of them were more accurate than the ANOVA model. Based on the results of this study, we conclude that the birth weight of dromedary calves was more influenced by the dam's intrauterine rearing capacity and by the environment, management, and feeding of the pregnant female camels than the hereditary growth potential. Considerable differences were found among male dromedaries in their breeding values for the birth weight trait.
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Peso ao Nascer/genética , Camelus/genética , Animais , Feminino , Masculino , Fenótipo , Gravidez , Reprodutibilidade dos TestesRESUMO
In the present study, we evaluated the role of genetic, physiologic and environmental factors in affecting gestation length, calf birth weight and time of parturition in dromedary camels. Reproductive data were collected over a 10-year period at the world's first intensively managed, large-scale camel dairy farm. We hypothesized that environmental conditions (i.e. photoperiod) have a decisive effect on these reproductive parameters. The effect of various factors was tested with linear mixed models and variance component analysis. A total of 557 (13.1%) primiparous and 3691 (86.9%) multiparous parturitions were observed in 2,123 dromedaries. Parturitions had a pronounced seasonal distribution. The mean (±SE) length of gestation and mean (±SE) birth weight were 384.5⯱â¯0.17 days (nâ¯=â¯4,093, CVâ¯=â¯2.88%) and 34.5⯱â¯0.09â¯kg (nâ¯=â¯3,909, CVâ¯=â¯16.8%), respectively. All but one fixed factors (type of breeding) affected length of gestation and calf birth weight. Month of conception (27.1%), female camel (11.2%) and live-dead status of the calf (10.6%) were responsible for close to 50% of the variation in gestation length. At the same time, female camel (30.3%), parity (11.3%), year (6.9%) and month of parturition (6.2%) had the strongest relative influence on the variation in calf birth weight. Both reproductive traits showed a pronounced circannual variation. Mean length of gestation was longer by app. 18 days in dromedaries conceiving in November compared to those becoming pregnant in May. Average new-born weight was 4.4-4.9â¯kg higher in December compared to that in September and April. Dromedaries gave birth throughout the 24â¯h period, but most of the deliveries (nâ¯=â¯3,117, 74.1%) occurred from sunrise to sunset. The peak of deliveries was between 2 and 3 pm. Month of the year has a strong effect on the timing of deliveries. In contrast, the time from sunrise to parturition did not differ among the months. Peak of deliveries occurred 7-9â¯h after sunrise and the median of time from sunrise to parturition was 8â¯h and 24â¯min. These results give strong support to the original hypothesis. Seasonal changes were independent of nutritional factors, were associated with climatic conditions (i.e. photoperiod) and may reflect an endogenous circannual rhythm in foetal development. The dromedary camel could be a useful in vivo model to study the effect of the environment on feto-maternal communication, fetal development and timing of parturition.
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Camelus/fisiologia , Prenhez/fisiologia , Reprodução/fisiologia , Animais , Peso ao Nascer , Relógios Circadianos , Feminino , Fotoperíodo , Gravidez , Reprodução/genética , Estações do Ano , Fatores de TempoRESUMO
We monitored the major chemical composition of bulk dromedary camel milk by FT-MIR spectroscopy over a 5-year period. The results highly correlated with those determined with reference methods (râ¯>â¯0.985, pâ¯<â¯0.001). Production parameters showed significant (pâ¯<â¯0.001) seasonal and yearly changes. The overall mean fat, protein, lactose, solids-not-fat, and total solids concentrations of bulk dromedary camel milk were 2.87%, 2.94%, 4.15%, 8.00%, and 10.69%, respectively. Month of the year, year of the study, and level of production had a strong influence on bulk milk chemical composition and yield of milk components; however, the relative effect of season on composition was greater (proportion of variance app. 50%) compared to that of other factors of variation. The highest and lowest values were measured during winter and summer, respectively. Circannual variation in major milk components was associated with environmental conditions (photoperiod, temperature), whereas it was independent of nutritional factors.
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Camelus , Leite/química , Espectroscopia de Infravermelho com Transformada de Fourier , Animais , Feminino , Fotoperíodo , Estações do Ano , TemperaturaRESUMO
Knowledge about immunity to Middle East respiratory syndrome coronavirus (MERS-CoV) in dromedary camels is essential for infection control and vaccination. A longitudinal study of 11 dam-calf pairs showed that calves lose maternal MERS-CoV antibodies 5-6 months postparturition and are left susceptible to infection, indicating a short window of opportunity for vaccination.
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Doenças dos Animais/imunologia , Doenças dos Animais/virologia , Camelus/virologia , Infecções por Coronavirus/veterinária , Coronavírus da Síndrome Respiratória do Oriente Médio/imunologia , Doenças dos Animais/transmissão , Animais , Anticorpos Antivirais/imunologia , Bovinos , Doenças dos Bovinos/imunologia , Doenças dos Bovinos/transmissão , Doenças dos Bovinos/virologia , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Estudos Longitudinais , Coronavírus da Síndrome Respiratória do Oriente Médio/classificação , Coronavírus da Síndrome Respiratória do Oriente Médio/genética , Coronavírus da Síndrome Respiratória do Oriente Médio/isolamento & purificação , RNA Viral , ZoonosesRESUMO
The camel dairy industry has gone through major development in the last decade. The world's first large-scale camel dairy farm was established 10 years ago in Dubai, United Arab Emirates, and since then, several commercial and scientific projects have been started, and more studies have been published demonstrating increasing interest in camel milk. The aims of this paper are to summarize relevant published data on factors influencing milk production under intensive management, compare those with our own observations obtained from Emirates Industry for Camel Milk and Products (EICMP), and highlight areas of research that are indispensable for further development. As in other species, the most important factors influencing milk yield are genetic and individual variation, age, parity, stage of lactation, nutrition, management, season, photoperiod, etc. However, the precise role of the various factors has not been thoroughly studied in camels and based on our understanding of the basic physiological processes, endocrine control is minimal. In addition, machine milking of dromedaries is still at early stage and requires research for improvement of the technology and defining factors affecting and improving milk ejection. The role of environment (like photoperiod, nutrition) should also be investigated as there is significant annual variation both in milk quantity and quality that might influence the processing characteristics of raw camel milk. The large pool of animals and thoroughly recorded data at EICMP provide an excellent opportunity for increasing milk production and improving milk quality using various methods, like feeding, management, reproduction, selection, and breeding.
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Camelus/fisiologia , Indústria de Laticínios/instrumentação , Animais , Indústria de Laticínios/métodos , Feminino , Leite/química , Ejeção Láctea/fisiologia , GravidezRESUMO
Camel brucellosis is a widespread zoonotic disease in camel-rearing countries caused by Brucella melitensis and Brucella abortus. The aim of this study was the first genetic analysis of B. melitensis strains isolated from dromedary camels (Camelus dromedarius) using multiple-locus variable-number tandem repeat analysis (MLVA). MLVA 16 and its MLVA 8 and MLVA11 subsets were used to determine the genotypes of 15 B. melitensis isolates from dromedary camels (11 strains) and other host species (4 strains) from the United Arab Emirates and the results were then compared to B. melitensis MLVA genotypes from other parts of the world. Five, including two novel genotypes were identified with MLVA 8. MLVA 16 further discriminated these five genotypes to ten variants. The eleven camel isolates clustered into four main genetic groups within the East-Mediterranean and African clades and this clustering correlated with the geographic origin of the hosts (United Arab Emirates, Kingdom of Saudi Arabia and Sudan) and the date of their isolation. The camel strains were also genetically related to strains isolated from wild and domestic ruminants from their close habitat or from other parts of the world. Although limited number of strains were analysed, based on our data imported animals from foreign countries, local small ruminants and wildlife species are hypothesized to be the main sources of camel brucellosis in the United Arab Emirates. MLVA was successfully applied to determine the epidemiological links between the different camel B. melitensis infections in the United Arab Emirates and it can be a beneficial tool in future disease control programs.