Non-genetic factors influencing reproductive traits and calving weight in Saudi camels     

Sallal E. Almutairi  Ismaïl Boujenane  Abdelgader Musaad  Falah Awad-Acharari 《Tropical animal health and production》2010,42(6):1087-1092

Reproductive traits and calving weight were assessed in Saudi camels, and non-genetic factors influencing them were studied using data collected at Al Jouf centre from 1987 to 2009. Age at first conception, age at first calving, open period, calving interval, gestation length and weight at calving of camels averaged 42.3 months, 54.8 months, 10.6 months, 22.6 months, 377.5 days and 591.9 kg, respectively. A mixed model including the camel as a random effect was used to assess the effect of environmental effects on the traits studied. Age at first conception and age at first calving were affected by camel’s birth year. Open period and calving interval were not affected by parity or year of calving. However, camels that calved from October to February had a calving interval of 2.5 months higher than those that calved from March to September. Gestation length was affected by season and year of calving but not by parity or sex of calf. Camels calving from March to September had a gestation length 6.6 days shorter than those calving from October to February. Weight at calving was affected by parity and year of calving but not by season of calving. It was concluded that an improvement in camel reproductive traits is possible both through improving management systems and utilisation of controlled breeding techniques.  相似文献   

Genetic and nongenetic effects for milk yield and growth traits in Saudi camels     

Almutairi  Sallal E.  Boujenane  Ismaïl  Musaad  Abdelgader  Awad-Acharari  Falah 《Tropical animal health and production》2010,42(8):1845-1853

The study was based on a set of 256 records for milk yield at 305 days, 1,899 records of test day yield, and 466 growth records collected at Al Jouf center from 1987 to 2009. Except season of calving, milk yield at 305 days was affected by parity and calving year, whereas test day yield was influenced by parity, calving year, stage of lactation, and test milk day. Only birth year had a significant effect on all growth traits, whereas dam’s parity influenced weights at birth and 3 months, and birth season affected birth weight, weight at 6 months and average daily gain (ADG) 3–6 months. Variance components estimated using an animal model showed that heritability and repeatability estimates for milk yield at 305 days were 0.24 and 0.28, respectively. The corresponding estimates for test day yield were 0.22 and 0.66, respectively. Direct heritabilities were 0.37, 0.50, 0.60, and 0.85 for body weights at birth, 3, 6, and 12 months of age, respectively, and 0.25, 0.37, 0.49, and 0.29 for ADG 0–3, 3–6, 6–12, and 0–12 months, respectively. The annual genetic progress was 0.05 kg for milk yield at 305 days and 0.0003 kg for test day yield. Annual genetic gains during 23 years were 0.050, −0.185, 0.079, and 0.331 kg for body weights, respectively, and −9, −5, −4, and −13 g, for ADG, respectively. It was concluded that it is necessary to set up a field milk and growth recording system in order to collect a large number of records to check these estimates.  相似文献   

Factors influencing the prevalence of subclinical mastitis in lactating dromedary camels in Riyadh Region,Saudi Arabia     

Aljumaah RS  Almutairi FF  Ayadi M  Alshaikh MA  Aljumaah AM  Hussein MF 《Tropical animal health and production》2011,43(8):1605-1610

The purpose of this study was to determine the prevalence of subclinical mastitis in camels in Riyadh, Saudi Arabia and the factors influencing its incidence. A total of 740 quarter milk samples were collected from 47 camel herds belonging to Majahim, Maghatir, Shu’l, and Sufer breeds. California mastitis test (CMT) was used as a screening test for subclinical mastitis. Samples giving negative or trace CMT scores (0) were assigned to healthy quarters, while those giving positive scores of 1+ to 3+ were assigned to subclinically affected quarters. Logistic regression was used to assess the association of breed, parity, and stage of lactation with the prevalence of subclinical mastitis. Milk fat, protein, lactose, solid nonfat percentages and Na, Ca, and K concentrations were compared in CMT-positive versus healthy quarters. One third (33%) of tested quarters had subclinical mastitis based on CMT. The estimated probability of subclinical mastitis with the combined effects of breed, parity, and stage of lactation ranged from 15.8% to 54.6%. The risk of subclinical mastitis increased significantly with parity and with the early stage of lactation. The Shu’l breed had significantly higher prevalence of subclinical mastitis than other breeds. Significant decreases in protein, lactose, and solid nonfat, Ca and K concentrations and increase in Na concentrations were associated with subclinical mastitis. In conclusion, subclinical mastitis is prevalent in Saudi camels, and its incidence is influenced by breed, parity, and stage of lactation.  相似文献   

Genetic diversity and phylogeny of pearl millets [Pennisetum glaucum (L.) R. Br.] based on chloroplast trnL-F region     

Almutairi  Zainab M. 《Genetic Resources and Crop Evolution》2022,69(8):2849-2859

Local varieties of pearl millets in Saudi Arabia are heat- and drought-tolerant and are grown under various environments. Here, we evaluated the diversity of six local varieties based on sequencing and analysis of the trnL-F region of their chloroplast DNA that includes the genes of tRNA^Leu and tRNA^Phe and the intergenic spacer between them, trnL-F. The obtained sequences were 1171–1172 bp in length, including the complete sequences of the tRNA^Leu, trnL-F and tRNA^Phe regions. Three variable nucleotide sites were observed in the sequences of the Indian variety, whereas for each of the three varieties, Tihamah, Jazan, and Sayah, a single variable site was observed. The varieties, Yemeni and Baydhan, were identical for the entire analyzed sequence. The secondary structure of tRNA^Leu intron of Indian variety was distinct from the other five varieties, while Tihamah and Jazan were distinct in the secondary structure of trnL-F spacer. Additionally, Indian was distinct in the secondary structure of tRNA^Leu whereas Sayah and Jazan were distinct in the secondary structure of tRNA^Phe. Phylogenetic analysis with NCBI-retrieved accessions of the Pennisetum glaucum revealed close relationships between the investigated varieties with an exception of the Indian, which clustered separately from the other five varieties. The nucleotide polymorphism analysis revealed higher nucleotide diversity in the spacer between tRNA^Leu and tRNA^Phe than in the tRNA^Leu intron across the six local varieties. This study provides insights into the genetic diversity within local pearl millets, which is important for the conservation of the local varieties that exhibit exceptional adaptation to the harsh climate conditions in the Arabian Peninsula.

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