One of the most valuable traits in production and breeding is a sheep’s prolificacy which is influenced by several genes, one of which is the osteopontin ( OPN) gene. Thus, this study aimed to determine the effect of genetic variation within the OPN gene on Awassi ewe prolificacy. Genomic DNA was extracted from 123 single-progeny ewes and 109 twin ewes. Polymerase chain reaction (PCR) was used to amplify 4 sequence fragments (289, 275, 338, and 372 bp), representing exons 4, 5, 6, and 7 of the OPN gene. A 372 bp amplicon was identified with 3 different genotypes: TT, TC, and CC. Sequence analysis revealed a novel mutation in TC genotypes p.Q>R234. Statistical analysis revealed that the single nucleotide polymorphism (SNP) p.Q>R234 was associated with prolificacy. Ewes carrying the p.Q>R234 SNP had significantly ( P ⩽ .01) lower litter sizes, twinning rates, and lambing rates, and more days to lambing than those with the TC and TT genotypes. The p.Q>R234 SNP was confirmed to be responsible for lower litter size through logistic regression analysis. From these results, we can conclude that the missense variant p.Q>R234 adversely affects the traits of interest and shows that the p.Q>R234 SNP negatively influences the prolificacy of Awassi sheep. Based on this study, it is evident that ewes in this population carrying the p.Q>R234 SNP have a lower litter size and are less prolific.
Reproductive efficiency is a crucial factor in the economic viability of small ruminant exploitation. In spite of this, few producers utilize the available reproductive technologies related to hormonal interaction, which are vital for the economic sustainability of their operations. Therefore, this review aimed to investigate the potential effects of reproductive alterations and hormone interactions during pregnancy and lactation and to determine advanced technologies for sheep reproduction. In the modern era, breeding techniques, nutrition, reproduction, and management techniques are used to produce more and better quality livestock. A combination of estrous synchronization and genetic improvements for small ruminants is needed to increase reproduction efficiency, productivity, and quality. A proper match between sheep breeds and nutritional and production environments will allow animals to express their genetic potential for enhanced production. In sheep, little information is available regarding the reproductive physiology during pregnancy and lactation. The availability of such information would enhance sheep production and reduce economic losses through improved dam performance and lamb survival. Understanding ewe reproductive physiology during pregnancy and lactation is essential for flock managers to determine their reproductive potential. Using advanced reproductive technologies could enhance the productivity of sheep, which are the most abundant ruminant livestock species.
Reproductive traits are affected by many factors, including ovarian function, hormones, and genetics. Genetic polymorphisms of candidate genes are associated with reproductive traits. Several candidate genes are associated with economic traits, including the follistatin ( FST) gene. Thus, this study aimed to evaluate whether the genetic variations in the FST gene are associated with the reproductive traits in Awassi ewes. The genomic DNA was extracted from 109 twin ewes and 123 single-progeny ewes. Therefore, 4 sequence fragments from the FST gene were amplified using polymerase chain reaction (PCR) (exon 2/240, exon 3/268, exon 4/254, and exon 5/266 bp, respectively). For a 254 bp amplicon, 3 genotypes were identified: CC, CG, and GG. Sequencing revealed a novel mutation in CG genotypes c.100C > G. The statistical analysis of c.100C > G showed an association with reproductive characteristics. Ewes carrying the c.100C > G had significantly ( P ⩽ .01) lower litter sizes, twinning rates, lambing rates, and more days to lambing compared with CG and CC genotypes. Logistic regression analysis confirmed that the c.100C > G single-nucleotide polymorphism (SNP) is responsible for decreasing litter size. According to these results, the variant c.100C > G negatively affects the traits of interest and is associated with lower reproductive traits in Awassi sheep. As a result of this study, ewes carrying the c.100C > G SNP have lower litter size and are less prolific.
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