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This study aimed to estimate genetic parameters, including heritability and repeatability, for milk yield and prolificacy in sheep. It included 3682 records from 1837 ewes across various breeds: Awassi, Assaf, and Awassi x Assaf crosses, two Awassi lines: Improved Awassi, AFEC Awassi. The study measured total milk yield (TMY), yield up to 120 days (TMY120), and yield up to 150 days (TMY150), alongside reproductive traits: litter size (LS), number of lambs born alive (NLBA), and lambing interval (LI). The analysis utilized a mixed model and the REML procedure to estimate genetic parameters. Results indicated that litter size (LS) had no significant impact on milk traits, whereas breed, location, ewe parity, and lambing season showed significant effects. Lactation length also significantly influenced TMY. For reproductive traits, treatment was significant for NLBA, with location associated with breed, parity, and season affecting all traits. Heritability estimates for TMY ranged from 0.00 in Awassi x Assaf crosses to 0.11 in Awassi, and for TMY120 and TMY150, from 0.00 in Awassi x Assaf crosses to 0.16 in Awassi. Estimates for LS and NLBA varied similarly. The heritability for LI was 0.03 in Awassi and zero in other breeds and crosses. The findings suggest that in the northern West Bank regions of Nablus and Jenin, Assaf or Awassi x Assaf breeds are preferable. The study underscores the importance of comprehensive performance and pedigree recording for effective sheep farm management., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Awassi is a fat-tailed sheep breed, and the best breed in Syria is famous. Awassi sheep are Syria's main source of red meat and milk production. In this study, we estimated the influence of various factors on sheep meat and milk production using time-series data from 1961 to 2020. This study employed the Cobb-Douglas production function to analyze the data. The results obtained indicate that Awassi meat production in Syria was positively and significantly influenced by carcass weight ( p  < 0.001) and quantity of slaughtered sheep ( p  < 0.001), with elasticity coefficients of 0.994 and 1.000, respectively. The model results show that raw milk yield and milk animals have a positive and significant influence on milk production at the 0.1 % significance level, with an elasticity coefficient of 0.998. However, climatic factors (precipitation and temperature) have a significant effect and negative influence on milk production at the 1 % and 5 % significance levels, respectively. This result sheds light on the policies and procedures the government should implement to develop sheep production in Syria. Therefore, it can be stated that policymakers should enhance the quality and productivity characterization of sheep through the implementation of breeding programs, improve grazing potential, and protect natural pastures. Furthermore, feed rations should be supported to help breeders overcome the effects of drought and high feed prices., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Author.)

This study was conducted to assess the association between proopiomelanocortin (POMC) gene and growth traits in Awassi and Karakul sheep. PCR-single strand conformation polymorphism (SSCP) method was utilized to assess the polymorphism of POMC PCR amplicons with body weight and length, wither and rump height, chest and abdominal circumference measured at birth, 3, 6, 9, and 12 months intervals. Only one missense SNP (rs424417456:C > A) was detected in exon-2, in which glycine was converted to cysteine in the 65th position in POMC (p.65Gly > Cys). rs424417456 SNP showed significant associations with all growth traits in the third, sixth, ninth, and twelfth months. At the age of 3 months onward, lambs with CC genotype showed higher body weight, body length, wither and rump heights, and chest and abdominal circumferences than lambs with CA and AA genotypes, respectively. Prediction analyses indicated a deleterious effect of p.65Gly > Cys on POMC structure, function, and stability. Owing to the strong correlation between rs424417456:CC and better growth characteristics, this genotype is proposed as a promising marker to enhance growth traits in Awassi and Karakul sheep. The predicted damaging effects caused by rs424417456:CA and rs424417456:AA genotypes may entail a putative mechanism through which lambs with these genotypes exhibit lower growth traits.

Scrapie is a fatal, neurodegenerative disease that affects sheep and goats, and genetic susceptibility to scrapie in sheep is associated with polymorphisms in the prion protein ( PRNP ) gene. The aim of this study is to identify PRNP polymorphism in Awassi sheep from Türkiye, the Palestinian Authority, and Saudi Arabia. A total of 150 healthy sheep were genotyped for PRNP , using Sanger sequencing. There were seven alleles and eleven genotypes observed based on codons 136, 154, and 171 of PRNP . The ARQ allele was predominant in all populations. The most resistant allele to scrapie, ARR, was present in all three regions. The VRQ allele, associated with the highest susceptibility to scrapie, was detected only in Türkiye at a low frequency. In this study, twenty-seven amino acid substitutions were found. Eight of them (R40Q, G65E, H88L, S98T, A118P, S138T, V192F and L250I) have not been previously reported. These data indicate that sheep breeds close to the sheep domestication center have maintained high genetic diversity in the PRNP region. Our findings on PRNP will provide valuable insights for sheep breeding programs, aiding in the selection of genotypes resistant to scrapie in Türkiye, the Palestinian Authority, and Saudi Arabia.

Birth weight (BW), which is the first physiological record of the postnatal period, is an important indicator that affects growth and development, reproduction, and some yields of living things in the future. The present study was carried out using the birth records of 5417 heads of Awassi lambs from 2013 to 2018 in MeMuTa dairy sheep farm in Zengen town of Ereğli district of Konya city in Türkiye. In this study, the effects of some environmental and genetic factors on birth and weaning weight in Awassi lambs were evaluated using both general linear model (GLM) and classification and regression tree (CART) analysis. As a result of the GLM analysis, the least squares' means of birth and weaning weights (BW and WW) were determined as 4.15 ± 0.05 kg and 16.39 ± 0.13 kg, respectively. Fixed genetic factors such as birth type and sex, and environmental factors such as season and year were found to be significant on birth weight (P < 0.01). As for weaning weight, other factors except birth type were found to be similarly important like birth weight (P < 0.01). Also, linear regression of birth weight on weaning weight was found to be significant (P < 0.01). In GLM and CART analyses, the determination coefficient (R 2 ) was determined to be 23.80% and 11.70% for BW, and 24.11% and 13.18% for WW, respectively. The findings of the analysis results showed that the factors in the model have a similar tendency both in terms of their relative ratios in the total variation in the GLM analysis and in their relative importance in the CART algorithm. It was seen that CART data mining algorithm in the prediction of some genetic and environmental factors on birth and weaning weights using some factors in Awassi lambs produced successful results in predictive performance. Briefly, it was determined that there is a similar tendency to GLM analysis according to CART algorithm analysis in the current study., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)

Fat-tailed sheep breeds are the most widespread types of sheep in the Middle East. They are hardy and have acceptable growth and carcass traits. The purpose of this study is to compare the fattening performance, nutrient digestibility, and carcass characteristics of two fat-tailed sheep breeds, Awassi and Najdi. Thirty single-born Awassi and Najdi male lambs (15 lambs per breed) were examined for fattening and carcass characteristics. The study lasted 70 days (10 days adaptation period and 60 days for collecting the data). Feed consumption was monitored daily, and the body weight of lambs was recorded upon arrival to the trial area and biweekly afterward. Lambs were slaughtered at the end of the study to assess carcass and meat quality characteristics. Nitrogen intake and retained nitrogen were higher (P < 0.05) for Najdi lambs. The digestibility of nutrients was comparable between the two genetic groups. Initial body weight, final body weight, average daily gain, and dry matter intake were not affected (P > 0.05) by the lamb's breed. Furthermore, the feed-to-gain ratio, hot and cold carcass weights, and dressing percentage were not affected by breed type (P > 0.05). Breed type has no influence on the shoulder, loin, and rack percentages of the lamb. Moreover, meat quality traits were not affected by the lamb's breed (P > 0.05). In the dissected leg cut, no differences in the leg component were found among the two breed types (P > 0.05). Results of this study reveal that nitrogen intake and retained nitrogen were higher for Najdi lambs, but this was not reflected in fattening performance and carcass traits., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)

The lipase E hormone-sensitive (LIPE) enzyme is one of the lipolytic enzymes, and it plays a key role in the regulation of adipose tissue deposition. This study was conducted to investigate the possible association between the LIPE gene variations and the main body weight measurements in Awassi sheep. A total of 160 of sexually mature Awassi rams (Ovis aries) that aged between 2 and 3 years were included in the present study. Genomic DNA was extracted and two specific PCR amplicons were designed to amplify two coding regions within the LIPE gene. Genotyping experiments were performed using polymerase chain reaction-single-strand conformational polymorphism (PCR-SSCP). Two different SSCP banding patterns were identified, CC and CD in exon 2, and AA and AT in exon 9. Five novel single-nucleotide polymorphisms (SNPs) were detected by sequencing, namely g.151C > A and g.198C > T in exon 2, and g.213G > C, g.226G > T, and g.232A > C in exon 9. Haplotype block analysis showed strong linkage disequilibrium values between the two SNPs in exon 2 and the three SNPs in exon 9. Association analysis of haplotypes with carcass traits demonstrated a significantly higher dressing percentage (P < 0.05) and lower fat tail weight (FTW) in CACT and GCGTAC haplotypes made these haplotypes more favorable for human consumption. The current research is the first one to report a tight association between the LIPE genetic polymorphism and the dressing percentage and FTW traits, suggesting a pivotal role played by these co-inherited SNPs in the metabolism of carcass traits in sheep.

The effect of replacing 13.6% and 20.3% of a total ration of fattening Awassi lambs by two combinations of fresh saltbush (Atriplex halimus) and fresh spineless cactus (Opuntia ficus-indica) cladodes at a ratio of 1.9:1 (TRT1) and 1.7:1 (TRT2) on water intake, digestibility, blood metabolites, and fattening performance was evaluated. Thirty-six lambs with average initial live weight 34.5 ± 4.18 kg were randomly assigned to three diets (control, TRT1, and TRT2). The control received a diet containing 166 g/kg barley straw and 834 g/kg of commercial concentrate mixture; TRT1 comprised 126 g barley straw, 739 g/kg concentrate mixture, 47 g/kg spineless cactus, and 89 g saltbush; TRT2 comprised 67 g/kg barley straw, 704 g/kg commercial concentrate mixture, 86 g/kg spineless cactus, and 144 g saltbush. A growth trial of 100 days (10 days of adaptation and 90 days of collection) followed by a metabolism trial of 17 days (10 days of adaptation and 7 days of a total feces and urine collection) was carried out. Daily dry matter intake, digestibility of crude protein, ether extract and nutrient detergent fiber, nitrogen balance, average daily gain, feed conversion ratio, and blood metabolites were not significantly affected by the treatment. Water consumption in TRT2 was significantly 16% less compared with the control. A combination of saltbush and spineless cactus at a ratio of 1.7:1 (TRT2) replaced 60% of barley straw and 16% of concentrate mixture without adverse effects on health and growth performance of Awassi male lambs. This represents a potential reduction in feed costs for smallholder farmers.

Quality food for human consumption will always be the aim for animal producers. Quantity and composition of fat deposits (fatty acid profile) strongly influences meat quality in ruminants, especially via increasing conjugated linoleic acid (CLA) concentration, which is known to have beneficial anticarcinogenic, antiatherogenic, antidiabetic and cholesterol reduction properties for human health. Awassi lambs are one of the main and most consumed meat sources in the Middle East area; however, studies addressing the fat content of CLA and methods to enhance its concentrations in this breed are still rare. For this reason, the aim of this study was to evaluate the effect of adding two different oil sources (soybean oil (SBO) and sunflower oil (SFO) at two levels (1.8 and 3%)) on growth performance, carcass characteristics and fatty acid profile of fat in Awassi lambs. Oil supplementation had no effect on growth performance or carcass characteristics, while fatty acid composition changed according to the site of extraction. CLA concentrations were increased in the tail fat deposit, with 1.8% SBO and in intermuscular fat deposit with 3% SFO. Intermuscular fat is the one most naturally consumed by humans, serving to improve food quality., (© 2013 Japanese Society of Animal Science.)