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Paratuberculosis is a chronic disease of ruminants caused by Mycobacterium avium subspecies paratuberculosis (MAP). It occurs worldwide and causes a significant loss in the animal production industry. There is no cure for MAP infection and vaccination is problematic. Identification of genetics of susceptibility could be a useful adjunct for programs that focus on management, testing and culling of diseased animals. A case-control, genome-wide association study (GWAS) was conducted using Holstein and Jersey cattle in a combined analysis in order to identify markers and chromosomal regions associated with susceptibility to MAP infection across-breed. A mixed-model method (GRAMMAR-GC) implemented in the GenABEL R package and a Bayes C analysis implemented in GenSel software were used as alternative approaches to conduct GWAS analysis focused on single SNPs and chromosomal segments, respectively. After conducting quality control, 22 406 SNPs from 2157 individuals were available for the GRAMMAR-GC (Bayes C) analysis and 45 640 SNPs from 2199 individuals were available for the Bayes C analysis. One SNP located on BTA27 (8·6 Mb) was identified as moderately associated (P < 5 × 10-5, FDR = 0·44) in the GRAMMAR-GC analysis of the combined breed data. Nine 1 Mb windows located on BTA 2, 3 (3 windows), 6, 8, 25, 27 and 29 each explained ≥1% of the total proportion of genetic variance in the Bayes C analysis. In an analysis ignoring differences in linkage phase, two moderately significantly associated SNPs were identified; ARS-BFGL-NGS-19381 on BTA23 (32 Mb) and Hapmap40994-BTA-46361 on BTA19 (61 Mb). New common genomic regions and candidate genes have been identified from the across-breed analysis that might be involved in the immune response and susceptibility to MAP infection.

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Background and Aim: Sheep productivity in developing countries is crucial, as this animal is an essential source of meat and wool. Myostatin (MSTN) plays an important role in the regulation of muscle mass through the regulation of muscle growth, differentiation, and regeneration. The present study sought to investigate genetic variation in the first intron of the MSTN gene and the association of variants with growth traits in major sheep breeds in Egypt (Barki, Ossimi, and Rahmani) and Saudi Arabia (Najdi) using polymerase chain reaction (PCR) and sequencing. Materials and Methods: Blood samples were collected, and DNA was extracted from 75 animals. A 386 bp fragment in the first intron of the MSTN gene was amplified using PCR. Polymorphic sites were detected using direct sequencing and then correlated with growth traits using a general linear model. Results: Sequence analysis of the first intron of MSTN gene identified six single-nucleotide polymorphisms (SNPs) in the studied breeds. Four mutual SNPs were determined: c.18 G>T, c.241 T>C, c.243 G>A, and c.259 G>T. In addition, two SNPs c.159 A>T and c.173 T>G were monomorphic (AA and TT, respectively) in the Ossimi, Rahmani, and Najdi breeds and polymorphic in the Barki breed. The association analysis revealed that the c.18 G>T and c.241 C>T significantly associated (p<0.05) with birth weight and average daily weight gain, respectively. Conclusion: Our results strongly support MSTN as a candidate gene for marker-assisted selection in sheep breeding programs. Furthermore, the identified variants may be considered as putative markers to improve growth traits in sheep.

Background: Thoracic and lumbar fractures represent nearly 90% of traumatic spine injuries. Thoracolumbar region is susceptible to injury because of its location between the stiff kyphotic thoracic spine and the mobile lordotic lumbar region. To compare between short-segment fixation with screws into index level and long-segment fixation in maintaining angle of correction and pain. Methods: A prospective study included 91 patients, who had single-level thoracolumbar fracture with Cobb's angle ≤ 25°and underwent posterior fixation. Forty-four patients underwent short-segment fixation with screws into the index level, and 47 patients underwent long-segment fixation with skipped index level. The angle of correction, pain, and neurological state were regularly assessed. Results: Forty-four patients (48.35%) had short segment and 47 (51.65%) had long-segment fixation. In the short segment group, the pre-operative mean Cobb's angle was 19.34°± 3.63°and the angle of correction was 8.14°± 1.9°a fter 1 year, while in the long segment group, the pre-operative mean Cobb's angle was 19.08°± 4.0°and the angle of correction was 8.62°± 2.59°. Regarding pain, in the short segment group, the pre-operative visual analogue scale (VAS) was 5.59 ± 2.09 that was reduced to 1.39 ± 0.58 at the 1 year follow-up, while the long segment group VAS was 5.4 ± 2.01 pre-operatively that was reduced to 1.47 ± 0.58. Conclusions: Short-segment fixation can maintain the angle of correction as long-segment fixation for single level thoracolumbar traumatic fracture with lower complication and faster pain relief. Trial registration: Clinicaltrials.gov/NCT03272243.