<div>Background:&nbsp;Circular RNAs (circRNAs), a novel class of endogenous non-coding RNAs with covalently closed loop structures, play important role in mammalian growth and development by regulating gene expression and participating in various biological processes. The aim of this study was to identify the expression profiles of circRNAs in the ovaries of Hu sheep and local Fat-tailed sheep during the luteal phase to determine the molecular mechanisms underlying the effects of circRNAs on reproduction and follicular development in sheep. 
 
Methods: To identify the differentially expressed circRNAs expressed in luteal phase conditions in Hu sheep and fat-tailed sheep, ovarian samples collected during the luteal phase were analyzed using high-throughput sequencing and subsequent transcriptomic approaches and bioinformatics analysis. 
 
Result:&nbsp;A total of 2,875 differentially expressed circRNAs were identified by high-through sequencing. Gene Ontology terminology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis showed that the host genes were mainly involved in the secretion and metabolism of the various pathway. Quantitative real-time PCR was performed to validate the results of expression profiling. These results contributed to an improved understanding of circRNA and the biological mechanisms of ovarian reproduction in sheep.</div>

Identification of Circular RNAs in the Ovaries of Hu Sheep and Local Fat-tailed Sheep during the Luteal Phase

<div>Background: MicroRNAs (miRNAs) are active regulators of numerous biological and physiological processes and play an important role in the regulation of animal ovaries and other reproductive related organs. To understand the molecular mechanisms of miR-10 family, we investigated the molecular characteristics and the relative expression of sheep miR-10a and miR-10b (miR-10a/b) and conducted bioinformatics analysis. 
 
Methods: During the period 2018-2019 total of 20 samples including blood and tissues such as hypothalamus, pituitary and ovary were collected from the Hu sheep raised in the National Meat Sheep Experimental Station of China (Luoyang City, Henan Province, China). Blood was collected from jugular vein by vacuum and anticoagulation blood collection tube and stored in refrigerator at -20&deg;C. The tissues were placed into the cryopreservation tube treated with Diethy pyrocarbonate (DEPC) water and stored in liquid nitrogen. All the samples were processed for isolation and confirmed with biochemical analysis and Polymerase chain reaction (PCR) and Real-time fluorescence quantitative PCR. 
 
Result: The target genes were predicted by three kinds of target gene predicting software. The function of target genes and their involved pathways were obtained by gene ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. The relative expression of miR-10a/b in sheep ovary was extremely significantly higher than that in hypothalamus and pituitary gland (P &lt; 0.01). The relative expression of miR-10b in ovary or pituitary was extremely significantly higher than that of miR-10a (P &lt; 0.01) and the relative expression of miR-10b in hypothalamus was significantly higher than that of miR-10a (P &lt; 0.05). These results serve as a foundation for further study on the Sheep miR-10 family.</div>

<div>Cloning, Characterization and Bioinformatics Analysis of the Sequences of miR-10a and miR-10b in Sheep (Hu sheep)</div>

<div style="text-align:justify">Background: The difference in the maternal behavior expression of sheep can affect the early growth and development as well as the survival of lambs. The characteristics of maternal behavior in primiparous and multiparous ewes were observed to reveal the expression of maternal behavior in Chinese Hu sheep and its effects on early lamb survival and body weight. 
 
Methods: In total 527 pregnant ewes with delivery were selected, including 246 primiparous ewes and 281 multiparous ewes. The observation record of maternal behavior began from 10 days before delivery to 3 days after delivery by video recording. The behaviors of ewe to the lamb included licking, suckling, seeking lambs, denial of suckling after delivery, butting and trampling lambs, abandoning lambs, and stealing lambs. Body weight of lambs were recorded including newborn, 7-day-old, 14-day-old and 35-day-old (weaning). 
 
Result: There were significant differences in the incidence rate in lamb abandonment and stealing between primiparous and multiparous ewes (P&lt;0.05), namely the primiparous ewe group had the higher incidence of undesirable behaviours. However, there were no significant differences in seeking, licking and trampling behaviors between two groups (P&gt;0.05). Lamb survival within 7 days after delivery of multiparous ewes was greater than primiparous ewes (P&lt;0.05). The body weights of newborn and 7-day-old lambs in the multiparous ewe group were significantly higher than the primiparous group (P&lt;0.05). This study demonstrates that limited significant differences exist between primiparous and multiparous ewes in several aspects of maternal behavior in Chinese Hu sheep. Ewe behavioral expression associated with the birth and care of the neonatal lambs are essential for the survival and growth of the offspring.</div>

<div style="text-align:justify">The Expression of Maternal Behavior in Chinese Hu Sheep and its Effects on Lamb Survival and Body Weight</div>

Background: Plant essential oil is used as a feed additive instead of antibiotics, but there is little research on its application in ruminants. Therefore, it is very necessary to study the effects of essential oil on growth performance, rumen fermentation and nutrient digestibility of Hu sheep. 
&nbsp; 
Methods: 96 weaned male Hu sheep, weighing 17.69&plusmn;0.20 kg, were randomly divided into 3 groups (control, 300 mg/kg and 600 mg/kg essential oil), with 4 replicates per group and 8 sheep per replicate. The pre-feeding period was 10 days and the full trial period was 61 days. 
&nbsp; 
Result: The results showed that the final weight of Hu sheep increased significantly (P&lt;0.05) and the rumen liquid ammonia nitrogen decreased significantly (P&lt;0.05) in the 600 mg/kg essential oil group when compared with the control group. The addition of essential oil to the diet had no significant effect on the rumen pH, volatile fatty acids and the digestibility of various nutrients. In conclusion, the diet addition of 600 mg/kg essential oil was better than 300 mg/kg for weaned Hu sheep performance, which can improve the growth performance and reduce the ammonia nitrogen of the rumen fluid. Essential oil can be added to Hu sheep feed as a good feed additive. 
&nbsp;

Effect of Essential Oil on Growth Performance, Rumen Fermentation and Nutrient Digestibility of Hu Sheep

Background: Litter size represents a key economic trait in Australian-Hu sheep (Australian White sheep&nbsp;♂&nbsp;&times; Hu sheep&nbsp;♀) and determines breeding profitability. Growth differentiation factor 9 (GDF9) is recognized as a principal candidate gene influencing litter size in ovis aries. Previous research on Australian-Hu sheep has focused on associations between polymorphisms in the coding region of GDF9 and litter size, with limited attention to the promoter region. To address this gap, this study examined the GDF9 promoter region polymorphism in Australian-Hu sheep, analyzed its association with multiple lambing and evaluated its impact on promoter activity, aiming to provide a theoretical foundation for selecting molecular markers for multiple lambing breeding. 
 
Methods: To investigate single nucleotide polymorphism (SNP) loci effects in GDF9 promoter region on lambing rate of Australian-Hu crossbred sheep, 193 pregnant ewes were selected. Genomic DNA (gDNA) was extracted from blood, the GDF9 promoter region was amplified by PCR and SNP sites were identified using Sanger sequencing. Association analyses between SNPs and lambing rate were conducted and a dual-luciferase reporter assay evaluated the SNPs&rsquo; effects on GDF9 transcriptional activity. 
 
Result: In the GDF9 promoter region of Australian-Hu Sheep, six linked SNP sites were identified: g.42117805C&gt;T, g.42117824T&gt;C, g.42117899G&gt;A, g.42118070A&gt;G, g.42118197T&gt;G and g.42118272C&gt;T. Five loci (g.42118070A&gt;G, g.42118272C&gt;T, g.42117805C&gt;T, g.42117824T&gt;C and g.42117899G&gt;A) showed significant association with lambing rate (P&lt;0.05), with heterozygous genotypes yielding higher lambing rate. Dual-luciferase reporter assays indicated that the (-517 to +3) region functions as the core promoter. Mutations at g.42118070A&gt;G, g.42118197T&gt;G and g.42118272C&gt;T within this region reduced GDF9 promoter transcriptional activity. These findings provide a basis for identifying molecular markers to screen for multiple lambing traits in Australian-Hu sheep.

Identification of GDF9 Promoter SNPs Affecting Lambing Rate in Australian-Hu Sheep

<div>Background: The estrous synchronization has become a worldwide available solution for modern management and large-scale cultivation of sheep. The objective of the present study was to compare the efficacy of three estrus synchronization protocols, CIDR9+PGF2&alpha;+eCG; CIDR14+eCG and GnRH+PGF2&alpha;, in Hu sheep. 
 
Methods: This study was conducted on 80 multiparous ewes, which were assigned into four groups: CIDR9+PGF2&alpha;+eCG; CIDR14+eCG; GnRH+PGF2&alpha; and control. Behavioral estrus was checked with teaser rams. Percentage of ewes behaving estrus at different time (0-24 h, 24-48 h, 48-72 h, respectively) was recorded. Pregnancy diagnosis was implemented on day 28 and confirmed on day 60 after insemination.&nbsp; 
 
Result: The results suggested that the estrus rate, pregnancy rate, conception rate, lambing rate and prolificacy in three treatment groups have no significant difference compared with control group. Most notably, CIDR9+PGF2&alpha;+eCG and CIDR14+eCG have significantly shorter duration of pregnancy than control. While CIDR14+eCG and GnRH+PGF2&alpha; did not dramatically change the fecundity of ewes, still CIDR9+PGF2&alpha;+eCG significantly decreased the fecundity of that compared with the control. Estrus responses in CIDR9+PGF2&alpha;+eCG, CIDR14+eCG and GnRH+PGF2&alpha; groups rose gradually to attain their significantly higher percentages (56.3%, 52.9% and 66.7%, respectively) during 24-48 h post-estrous detection, afterwards, they fell down.</div>

The Efficacy of Three Different Estrus Synchronization Protocols on Reproductive Performance in Chinese Hu Sheep

<div>Background: The study of the homology of loci between different species has allowed the improvement of specific genetic knowledge and the development of several fundamental concepts. Thanks to this method, Wright discovered the correspondence between a gene and an enzyme (Wright, 1917). In ruminants, this correspondence between loci of different species has been demonstrated for a very long time (Lauvergne, 1979). In fact, the objective of this work was, initially, to use microsatellites recommended for sheep (FAO, 2011) for the amplification of bovine DNA to show that these loci are homologous and, then, to study the genetic diversity and population structure of three groups of each of the two species in Tunisia. 
 
Methods: In this study, we used three microsatellite markers (OarFCB304, OarFCB193 and MAF209) to verify whether they can be amplified in both sheep and cattle. For that, we considered 28 samples of sheep species from 3 different populations and 17 samples of cattle belonging to three breeds. The data obtained were also used to study their genetic diversity and population structure.&nbsp; 
 
Result: We have demonstrated the existence of microsatellite regions common to sheep and cattle. Regarding genetic diversity, we observed a heterozygous deficiency in all the studied breeds. Nei&rsquo;s genetic distances were greater between breeds of cattle than between breeds of sheep.</div>

Detection of Homologous Loci in Sheep and Cattle

<div>Background: Hassan sheep is the third most populous breed of the five registered sheep breeds from Karnataka with limited studies on its morphological and carcass characteristics. Hence, the study was undertaken to know the present status of morphological and carcass characteristics of this breed. 
 
Methods: A total of 34 randomly selected flocks were surveyed and the data on various parameters were collected. The morphometrical data was collected on 344 sheep belonging to eight flocks from the breeding tract. The carcass characteristics were documented by slaughtering six male lambs (between nine to twelve months of age). 
 
Result: These sheep had varied coat colours viz. complete white (23.3%), white with light brown patches (58.1%) and white with black patches (18.6%) on head and neck region. It was observed that 40.4 per cent of males and only 1.4 per cent of females were horned. Atrophied ears were noticed in 2.3 per cent of these sheep. The average adult body length (cm), height at wither (cm), chest girth (cm), paunch (cm), ear length (cm), tail length (cm) and average adult body weight (kg) were 66.4&plusmn;0.62, 65.03&plusmn;1.45, 75.2&plusmn;1.02, 76.5&plusmn;1.38, 15.2&plusmn;0.07, 11.5&plusmn;0.07 and 32.7&plusmn;2.03 in males and 63.8&plusmn;0.85, 61.7&plusmn;1.38, 71.8&plusmn;2.32, 74.5&plusmn;2.60, 15.0&plusmn;0.34, 11.3&plusmn;0.08 and 27.8&plusmn;1.21 in females, respectively. The difference in body weight between males and females increased significantly over the age. The pre-slaughter weight (PSW), hot carcass weight (HCW) and dressing percentage recorded were 20.3&plusmn;1.42 Kg, 9.5&plusmn;0.23 kg and 46.80 per cent, respectively.</div>

Phenotypic and Carcass Characterization of Hassan Sheep

<div style="text-align: justify;">This study has aimed to investigate the differences between the levels of trace elements in sheep with the diagnosis of ecthyma, and in healthy sheep. For this purpose, Be,Bi,Pb,Cd,Na,K,Ca,Mg,Fe,Cu,Zn,Se,Ni and Mn,Co,Cr,Li elements in the plasma of sheep with Contagious ecthyma detected with PCR and in sheep in the control group were analyzed with ICP-OES.In this study, the levels of Fe,Cu,Zn,Se and Pb trace elements were found to be statistically different between the sheep infected with parapoxvirus.The Na element of the macro elements was observed to be statistically different in sheep with ecthyma, to the control group(P&lt;0.05).When there are low levels of metal concentration in sheep with ecthyma, their immune system can be considered to be weakened.Further studies can be carried out on the increase in the risk of developing the disease as a result of, in particular, a decrease in the Fe,Cu,Zn and Se concentrations in sheep infected with the virus.</div>

The changes in the levels of elements in sheep with Contagious Ecthyma &nbsp;

<div>Background: The mutations in POU1F1 gene result in deficiency of GH, PRL and TSH-&acirc; expression and thus have an indirect effect on development and reproduction. The present study was conducted to determine and compare the polymorphism of POU1F1 gene in Mandya and NARI-Suwarna Sheep.&nbsp;&nbsp; 
 
Methods:&nbsp;Blood samples were collected from 50 each of Mandya and NARI-Suwarna sheep and genomic DNA was isolated following Miller&rsquo;s high salt method. PCR-RFLP analysis was performed for exon 3 and exon 4 regions of POU1F1 gene, whereas, PCR-SSCP analysis was performed for exon 6 region of POU1F1 gene.&nbsp; 
 
Result: The PCR products of sizes 365 bp, 508 bp and 501 bp for exon 3, exon 4 and exon 6 regions of POU1F1 gene, respectively were successfully amplified. PCR-RFLP analysis of exon 3 and exon 4 regions of POU1F1 gene with AluI and EcoRI restriction enzymes, respectively revealed monomorphism in both Mandya and NARI-Suwarna sheep. The PCR-SSCP analysis of exon 6 region of POU1F1 gene revealed two patterns, P1 and P2 with frequencies of 98 and 2 per cent, respectively in Mandya sheep and 90 and 10 per cent, respectively in NARI-Suwarna sheep. The alignment of P1 and P2 pattern sequences revealed two SNPs (109 G&gt;C and 112 T&gt;A) in Mandya sheep, whereas 3 SNPs (218 T&gt;G, 225 G&gt;A and 264 T&gt;A) were revealed in NARI-Suwarna sheep. Polymorphism was successfully established at exon 6 region of POU1F1 gene.&nbsp;</div>