Prolific Sheep Research Articles

Evaluation of performance and estimation of genetic parameters for milk yield and reproductive traits in Awassi and Asaf sheep breeds and crosses in the Palestinian territory.

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.

PSVII-11 Genetic parameter estimates for lamb survival in prolific and nonprolific ewes

Abstract Given the increasing global demand for animal products, increasing lamb survival is a key breeding objective for sheep. However, high prolificacy can be associated with increases in fetal and lamb mortality. Therefore, the goal of this study was to estimate the variance components and genetic parameters for lamb survival (LS), using a: 1) single-trait model, where all ewes are analyzed together; and 2) two-trait model, where ewes are grouped in two groups based on birth type [i.e., Group 1 (G1) = single lamb/ewe, and Group 2 (G2) = multiple lambs/ewe]. In both models, LS was defined as the survival of lamb from birth to weaning and analyzed as a threshold trait. A total of 1,040,629 records (215,075 from single and 825,554 from multiple birth) from 319,467 ewes from several breeds/breed groups were available for the study. There were no females with two different types of births. Variance components were estimated through Bayesian inference via Gibbs sampling implemented in the GIBBSF90+ program, fitting a two-trait animal model with maternal effects, in which breed/breed groups were included as fixed effects. Average number of lambs/ewe in G2 was 2.57 (SD = 0.72). Heritability estimated (± SE) for LS on the underlying scale using the single-trait (0.04 ± 0.10) and two-trait model (0.010 ± 0.001 for LSG1 and 0.031 ± 0.004 for LSG2) were low. Maternal heritability estimated by the single-trait model was 0.007 ± 0.043, while by the two-trait model the estimates were 0.010 ± 0.006 and 0.040 ± 0.005 for LSG1 and LSG2, respectively. The genetic correlation estimated between LSG1 and LSG2 was weak and positive (0.25 ± 0.21). The low non-significant genetic correlation between single and multiple birth groups suggests that lamb survival is a different genetic trait in different birth types. Therefore, selecting for improving LS in nonprolific ewes may not necessarily translate to improving LS in prolific ewes. This underscores the need for careful consideration and targeted breeding strategies to achieve desired outcomes in nonprolific and prolific sheep simultaneously. Further studies to define the optimal statistical approach to genetically evaluate LS in prolific and nonprolific ewes are warranted.

Elucidating the Genetic Regulation of Reproductive Prolificacy in Tibetan Sheep Through Ovarian Tissue Sequencing

Background: This study aims to unravel the genetic intricacies regulating the reproductive prolificacy of Tibetan sheep, an indigenous breed prominently found in the Qinghai-Tibet Plateau. Methods: We employed meticulous sequencing and analytical strategies to discern the differential expressions of long non-coding RNAs (lncRNAs) and messenger RNAs (mRNAs) in the ovarian tissues of ewes with varying lambing numbers. Result: In our study, we identified 817 genes with differential expression in twin-bearing ewes compared to those bearing single lambs. This group comprised 495 upregulated and 322 downregulated genes, featuring key candidates like COL1A1, COL1A2, BMPRIB, GDF9, BMP15 and TGFB2. Furthermore, we discovered a notable difference in the expression of long non-coding RNAs (lncRNAs) in ewes birthing twins as opposed to singles, with 210 differentially expressed lncRNAs identified, including 91 upregulated and 119 downregulated. Key genes and lncRNAs associated with reproductive efficiency were identified, contributing valuable insights into the underlying molecular mechanisms and offering a robust foundation for enhancing breeding strategies and overall livestock productivity.

Screening of <em>FecLL</em> prolific allele of the <em>B4GALNT2</em> gene in Algerian sheep populations

Background: Research on the main genes controlling prolificacy in sheep, also known as fecundity genes (Fec genes), has highlighted the mechanisms involved in ewe fertility and the genetic improvement of prolificacy. The gene, FecL/B4GALNT2 (beta-1,4-N-acetyl-galactosaminyl transferase 2) and its prolific allele FecLL, which segregate in French Lacaune sheep and some local sheep breeds in Morocco and Tunisia, were found to influence ovarian function. However, their action differs from that of other major genes discovered previously, such as: FecX/BMP15 (bone morphogenetic protein 15); FecG/GDF9 (growth differentiation factor 9); and FecB/BMPR1B (bone morphogenetic protein receptor type 1B). The latter act in the bone morphogenetic protein (BMP) signalling pathway. Aim: The objective of this study is to investigate the segregation of the FecLL allele in Algerian sheep populations. Methods: A total of 338 animals from 12 breeds were genotyped using the PCR-RFLP technique. Results: Our results revealed the presence of FecLL in the Algerian D’man sheep population. Among the genotyped D’man sheep, 21% were carriers of the mutation in the heterozygous state. The frequency of the FecLL allele in the Algerian D’man population (0.11) is close to what is observed in Lacaune sheep and remains relatively low compared to Moroccan (0.58) and Tunisian (0.65) D’man sheep. Conclusions: The FecLL allele, which is shared by the French Lacaune population and the North African D’man populations, could indicate the ancestral origin of the mutation in B4GALNT2 or the occurrence of an ancient introgression event to improve prolificacy. Managing this mutation in Algerian D’man flocks could help improve the numerical productivity of D’man sheep in Algeria.

Polymorphism of the BMP15 and GDF9 genes in Romanov, Wrzosówka, and Podhale Zackel sheep in Poland

Various mutations in the BMP15 and GDF9 genes belonging to the transforming growth factor-β (TGF-β) superfamily have been shown to affect the prolificacy in sheep. Increasing the litter size is critical to the profitability of sheep production, but focusing on increasing the number of lambs born is only one of many factors that make sheep farming profitable. The study aimed to identify polymorphisms in BMP15 and GDF9 in Romanov, Wrzosówka, and Podhale Zackiel sheep breeds. The polymorphism of the coding parts of the BMP15 and GDF9 genes was determined based on DNA sequence analysis. Statistical analysis showed a significant relationship (p≤0.05) between the identified leucine deletion at the BMP15 locus (c.28_30delCTT) and increased fertility in heterozygous sheep. Statistically significant differences in the level of fertility were also identified between individuals with a mutation in the GDF9 gene - (c.978A> G, G6 - c.994G> A) and carriers of mutations in two BMP15 genes and GDF9 simultaneously.

Polymorphisms of the BMPR1B, BMP15 and GDF9 fecundity genes in four Chinese sheep breeds

Abstract. Numerous studies on prolific sheep breeds have shown that the transforming growth factor beta (TGF-β) superfamily members, including bone morphogenetic protein receptor type 1B (BMPR1B), bone morphogenetic protein 15 (BMP15) and growth differentiation factor 9 (GDF9), are the essential regulators of ovulation rate and litter size. In total, 11 known mutations (1 in BMPR1B, 6 in BMP15 and 4 in GDF9) are able to increase the ovulation rate and litter size, respectively. In this study, the genomic DNA was isolated from 512 high-prolificacy sheep (including the Small-tailed Han, Hu and Wadi sheep breeds) and 164 low-prolificacy sheep (Tan sheep), and genotyping of the specific mutations of the three fecundity-related genes was carried out by sequencing. The results showed that the FecB mutation in BMPR1B was detected in all four sheep breeds, and the frequency of B allele was significantly higher in the high-prolificacy breeds than that in the low-prolificacy breed (P<0.001). A novel mutation, c.T755C (named S1), was found in BMP15 from the four sheep breeds. However, known mutations such as FecXI, FecXH, FecXB, FecXG, FecXL and FecXR were not detected in these breeds. Three known loci (G1, G3 and G4) and a new mutation, c.A1515G (named S2), were found in GDF9, and the other three known mutations (FecGH (G8), FecGE and FecTT) were not detected in all four sheep breeds. The genotype distribution at the G1 and G4 loci had significant differences between the low-prolificacy sheep breed and the other three high-prolificacy sheep breeds. There was no difference in the genotype distribution at the G1 and G4 loci between the three high-prolificacy sheep breeds. Haplotype analysis of the four polymorphic loci in GDF9 suggested that H4 (GGAA) was the preponderant haplotype in the three high-prolificacy sheep breeds, but H1 (GGGG) was in the low-prolificacy sheep breed. These results preliminarily showed that the BMPR1B and GDF9 might be major genes influencing the prolificacy of Chinese sheep breeds.

Transcriptome Analysis Reveals Differentially Expressed circRNAs Associated with Fecundity in Small-Tail Han Sheep Thyroid with Different FecB Genotypes.

Litter size is an economically important trait in sheep, and it is a complex trait controlled by multiple genes in multiple organs. Among them, the regulation of lamb number trait by the thyroid gland is a very important part. However, the molecular mechanisms of the thyroid gland in sheep reproduction remain unclear. Here, RNA-seq was used to detect transcriptome expression patterns in the thyroid gland between follicular phase (FP) and luteal phase (LP) in FecB BB (MM) and FecB ++ (ww) STH sheep, respectively, and to identify differentially expressed circRNAs (DECs) associated with reproduction. Bioinformatic analysis of the source genes of these DECs revealed that they can be enriched in multiple signaling pathways involved in the reproductive process of animals. We found that the source genes of these DECs, such as GNAQ, VEGFC, MAPK1, STAT1, and HSD17B7, may play important roles in the reproductive process of animals. To better understand the function of these DECs, we constructed circRNA-miRNA co-expression networks. Dual luciferase reporter assays suggested that a ceRNA regulatory mechanism between circ_0003259-oar-miR-133-TXLNA and circ_0012128-oar-miR-370-3p-FGFR1 may hold. All of these DEC expression profiles in the thyroid gland provide a novel resource for elucidating the regulatory mechanisms underlying STH sheep prolificacy.

LncRNA12097.1 contributes to endometrial cell growth by enhancing YES1 activating β-catenin via sponging miR-145-5p

Despite previous investigations elucidating the regulatory mechanisms of long non-coding RNAs (lncRNAs) in endometrial function and reproductive disorders, the precise pathways through which lncRNAs impact endometrial functions and fertility remain unclear. In this study, we performed an expression profile analysis of lncRNAs in the endometrial tissue of Hu sheep with different prolificacy, identifying 13,707 lncRNAs. We discovered a bidirectional lncRNA, designated lncRNA12097.1, exhibiting significant up-regulation exclusively in the endometrium of Hu sheep with high fecundity. Functional analyses revealed lncRNA12097.1 significantly enhanced proliferation and cell cycle progression in both endometrial epithelial cell (EEC) and stromal cells (ESC), while inhibiting apoptosis in these cell types. Mechanistically, we demonstrated a directly interaction between lncRNA12097.1 and miR-145-5p, with YES proto-oncogene 1 (YES1) being identified as a validated target of miR-145-5p. Interference with lncRNA12097.1 resulted in suppressed cell growth through down-regulation of YES1 expression, which could be rescued by miR-145-5p. Furthermore, lncRNA12097.1 functions as a competitive endogenous RNA (ceRNA) for miR-145-5p in ESCs, sequestering miR-145-5p and preventing its binding to the 3′UTR of YES1 mRNA. This interaction led to increased expression of YES1 and subsequent activation of downstream β-catenin signaling, thereby promoting ESC growth in Hu sheep. These findings provide novel molecular insights into the mechanisms underlying prolificacy in sheep.

A novel action of insulin sensitizing drug as a potential promotor of preovulatory follicles, ovulation rate and prolificacy in sheep.

The effect of the insulin-sensitizing drug metformin on preovulatory follicle (POF) number, ovulation rate, fetal rate and prolificacy was studied in forty-six cyclic Malpura ewes. After estrus synchronization, the ewes were equally divided into two groups (n = 23). The treatment group (MET) received a daily oral dose of metformin at a rate of 500mg/animal for approximately 12 weeks, spanning five estrous cycles, as against untreated control (CON). All the ewes were bred to proven rams at the end of treatment. Ovarian ultrasound scans were performed at each estrus and day 9 of each cycle to assess the number and diameter of POFs and corpora lutea (CL), respectively. A comprehensive assessment of circulating hormones including, estradiol, progesterone, androstenedione, and insulin as well as metabolic indicators such as glucose, and lipid profile parameters was performed. At the end of treatment on the day of estrus (E5D0), the treatment showed a stimulatory effect on follicular development with a 53.2% (P < 0.001) increase in the number of POFs. It also increased the ovulation rate by 67.4% (P < 0.01), with a higher proportion (χ2df1 = 10.7, P < 0.001) of ewes in the MET group having multiple ovulations compared to the CON group (82.6 vs. 30.4%). With 1.48 ± 0.12 prolificacy rate in MET ewes, the proportion of ewes giving birth to multiple lambs was 2.9-fold higher than in the CON group. Plasma estradiol, insulin, glucose, total cholesterol, and LDL-cholesterol concentrations were lower (P < 0.05) in the MET ewes than in the CON. The results of the present study indicate that metformin can increase the number of POF, ovulation rate, fetal rate and prolificacy in ewes, while reducing the plasma estradiol, insulin, glucose and cholesterol in MET ewes.

37 Precision Feeding of Prolific Sheep in Highly Productive Management Systems

Abstract Globally lamb production is constrained by seasonal reproduction and flock productivity. There is potential to reduce both with improved reproductive and nutritional management in systems with a reduced interbirth interval. These accelerated systems can improve productivity &amp;gt;2 times compared with conventional systems. Successful adoption of these systems has been hampered; however, by low and variable reproductive efficiency during the suboptimal breeding period (February to July). We designed a series of studies to address this problem using an 8-month birth interval system with Polled Dorset x Polypay ewes without the use of exogenous hormone or photoperiod therapies. In study 1, we examined prebreeding nutrition combined with the male effect on reproductive outcomes in both long (April/May) and short-day (Dec./Jan.) breeding seasons. Ewes were randomly allocated to one of 3 nutritional treatments after weaning during a 21-day prebreeding period: 50%, 100% or 200% of maintenance energy intake. Ewes were exposed to vasectomized rams the last 14 days of treatment followed immediately with fertile rams for a 34-day breeding period (22 to 27 ewes per vasectomized or fertile ram). Both litter size (1.60 short vs. 1.34 long) and conception (96% short vs. 86% long) were greater in the short season (P &amp;lt; 0.001). Nutrition did not impact conception in either season; however, litter size was increased 15% in long and 25% in short day breeding season in ewes fed 200% compared the other treatments. These results suggest that litter size can be improved in these systems regardless of season by elevating energy intake above current recommendations. In study 2, we examined the impact of energy status during 2 preconception periods: lactation (last 30 days of previous lactation) and flushing (21 days pre-breeding plus 34-day breeding period). During lactation ewes received either 70% (L), 100% (C), and 150% (H) of energy requirements according to litter size. During flushing, ewes received 70%, 100% and 160% of maintenance energy with reproductive management as for study 1. Blood samples collected every 3 to 4 days were analyzed for plasma progesterone concentration via radioimmunoassay. Season had a great impact on return to estrus with 18% of ewes exhibiting luteal phases before teaser ram introduction during long as compared with 99% during short-day season. Nutrition during lactation also impacted return to estrus but only in long days with 40% of ewes on the H diet exhibiting luteal phases compared with 14% on the L diet before teaser ram introduction. Collectively, this indicates that an increased rate on conception is possible without the use of exogenous hormones or photoperiod manipulation in accelerated systems. Furthermore, a high plane of preconception nutrition improves litter size regardless of season and may hasten return to estrus during the suboptimal breeding period.

Thyroid Transcriptomics Revealed the Reproductive Regulation of miRNA in the Follicular and Luteal Phases in Small-Tail Han Sheep with Different FecB Genotypes.

MicroRNA (miRNA) is a type of endogenous short-stranded ncRNA that influences many biological processes such as animal growth, development and metabolism. The thyroid gland is an important endocrine gland in sheep, and an increasing number of studies have shown that the thyroid gland plays an important role in animal reproduction, but the molecular mechanisms of the thyroid gland in sheep reproduction are poorly understood. In this study, RNA-seq was used to detect transcriptome expression patterns in the thyroid gland between the follicular phase (FP) and luteal phase (LP) in FecB BB (MM) and FecB ++ (ww) small-tail Han (STH) sheep, respectively, and to identify differentially expressed miRNAs (DEMs) associated with reproduction. Bioinformatic analysis of the target genes of these DEMs revealed that they can be enriched in multiple GO terms associated with the reproductive process in animals and in the KEGG signaling pathway. The miRNA-mRNA coexpression network revealed that oar-miR-133 and oar-miR-370-3p may play an important role in sheep reproduction. The results of the dual-luciferase reporter assay suggest a possible targeting relationship between novel-51 and TARBP2. These results provided a novel resource for elucidating regulatory mechanisms underlying STH sheep prolificacy.

Identification and analysis of differentially expressed microRNAs in endometrium to explore the regulation of sheep fecundity

BackgroundMicroRNAs (miRNAs) play an important regulatory role in mammalian reproduction. Currently, most studies are primarily concentrated on ovarian miRNAs, ignoring the influence of endometrial miRNAs on the fecundity of female sheep. To uncover potential regulators of sheep fecundity, RNA-seq was used to comparatively analyze miRNA expression profiles of endometrium between high prolificacy sheep (HP, litter size = 3) and low prolificacy sheep (LP, litter size = 1) with FecB genotype.ResultsFirstly, genomic features of miRNAs from endometrium were analyzed. Furthermore, 58 differentially expressed (DE) miRNAs were found in the endometrium of Hu sheep with different litter size. A co-expression network of DE miRNAs and target genes has been constructed, and hub genes related litter size are included, such as DE miRNA unconservative_NC_019472.2_1229533 and unconservative_NC_019481.2_1637827 target to estrogen receptor α (ESR1) and unconservative_NC_019481.2_1637827 targets to transcription factor 7 (TCF7). Moreover, functional annotation analysis showed that the target genes (NRCAM and NEGR1) of the DE miRNAs were significantly enriched in cell adhesion molecules (CAMs) signaling pathway, which was related to uterine receptivity.ConclusionTaken together, this study provides a new valuable resource for understanding the molecular mechanisms underlying Hu sheep prolificacy.

Screening for causative mutations in ovine BMPR1B and BMP15 genes and their homologous fragments in human.

The BMPR1B and BMP15 genes are well known for their considerable associations with prolificacy in sheep. These genes may also affect fertility or prolificacy in other species, including human. This study was conducted to investigate possible causative mutations in BMPR1B and BMP15 genes in human and an indigenous breed of sheep. Blood samples were collected from 83 singleton- and prolific Mehraban ewes and 81 infertile, singleton- and twin-bearing women. A 190-bp fragment, containing the FecB mutation in ovine BMPR1B, a 380-bp fragment in ovine BMP15 gene and their homologous fragments in human were amplified and then investigated by single-stranded conformation polymorphism and DNA sequencing methods. The FecB mutation of BMPR1B (g.159A>G) was detected in the sheep population, but no polymorphic loci were found in the homologous fragment in studied human samples. The studied fragments of BMP15 were monomorphic in both sheep and human samples. A total of nine and 69 point-differences in the studied fragments of BMPR1B and BMP15 genes were detected between the species, respectively. In sheep, the G allele of BMPR1B had a positive effect on litter size (p<0.05), whereby all AG or GG ewes were prolific. The FecB mutation for the first time was detected in Mehraban sheep and therefore could be considered for marker-assisted selection in this breed. The studied fragments of BMPR1B and BMP15 genes are not responsible for reproduction variation in human. More studies on other genes, associated with fertility in human, are necessary in the future.

Effects of rearing mode on gastro-intestinal microbiota and development, immunocompetence, sanitary status and growth performance of lambs from birth to two months of age

BackgroundArtificial rearing system, commonly used in prolific sheep breeds, is associated to increased mortality and morbidity rates before weaning, which might be linked to perturbations in digestive tract maturation, including microbiota colonization. This study evaluated the effect of rearing mode (mothered or artificially reared) on the establishment of the rumen and intestinal microbiome of lambs from birth to weaning. We also measured immunological and zootechnical parameters to assess lambs’ growth and health. GIT anatomy as well as rumen and intestinal epithelium gene expression were also analysed on weaned animals to assess possible long-term effects of the rearing practice.ResultsTotal VFA concentrations were higher in mothered lambs at 2 months of age, while artificially-reared lambs had lower average daily gain, a more degraded sanitary status and lower serum IgG concentration in the early growth phase. Metataxonomic analysis revealed higher richness of bacterial and eukaryote populations in mothered vs. artificially-reared lambs in both Rumen and Feces. Beta diversity analysis indicated an evolution of rumen and fecal bacterial communities in mothered lambs with age, not observed in artificially-reared lambs. Important functional microorganisms such as the cellulolytic bacterium Fibrobacter succinogenes and rumen protozoa did not establish correctly before weaning in artificially-reared lambs. Enterobacteriaceae and Escherichia coli were dominant in the fecal microbiota of mothered lambs, but main E. coli virulence genes were not found differential between the two groups, suggesting they are commensal bacteria which could exert a protective effect against pathogens. The fecal microbiota of artificially-reared lambs had a high proportion of lactic acid bacteria taxa. No difference was observed in mucosa gene expression in the two lamb groups after weaning.ConclusionsThe rearing mode influences gastrointestinal microbiota and health-associated parameters in offspring in early life: rumen maturation was impaired in artificially-reared lambs which also presented altered sanitary status and higher risk of gut dysbiosis. The first month of age is thus a critical period where the gastrointestinal tract environment and microbiota are particularly unstable and special care should be taken in the management of artificially fed newborn ruminants.

Description of White Blood Cell Difference and Health at Various Levels of Batur Sheep Prolification

Twenty Batur sheep were used in this study to know the description of white blood cells (lymphocytes, neutrophils, eosinophils, basophils, and monocytes) at various levels of prolification. The research material was selected according to the criteria, namely, the average age was 3 years, the condition was 2 months pregnant with at least 2 births at parity. Experimental animals were divided into two groups: 10 animals were categorized as high prolific (number of children ≥2 per birth) and 10 animals were categorized as low prolific (1 child per birth). All experimental sheep were given basal forage and drinking water ad libitum. The observed variables were the differentiation of granulocyte leukocytes which included basophils, eosinophils, and neutrophils, and agranulocyte leukocytes which included lymphocytes and monocytes. The data obtained were analyzed by unpaired student t-test (unequal). The results showed that the level of prolification had no significant effect (P&gt;0.05) on changes in lymphocytes, neutrophils, eosinophils, basophils, and monocytes. It was concluded that the appearance of lymphocytes, neutrophils, eosinophils, basophils, and monocytes between low prolific sheep and high prolific sheep were in the normal range with relatively the same concentration.

Marker-assisted introgression of fecundity mutation into Barbarine sheep breed under low input production system

Fecundity gene introgression has become an economical method to improve sheep prolificacy in developing countries. The FecXBar and FecGHmutations are variants of the BMP15 and GDF9sheep genes,respectively, identified in Tunisian Barbarine sheep prolific line "W-INRAT," created through a prolificacy-based selection program. The firstmutation caused increased prolificacy in heterozygous state and sterility in homozygous ewes. The aim of this work was to increase the number of effective carriers by the introgression of fecundity mutation into non-carrier conventional flocks based on a marker-assisted breeding program. The genotyping was carried out to follow up on the segregation of prolificacy mutation. The conventional ewes, raised in state farms of Tunisia and inseminated by "W-INRAT" rams, yielded 100% carriers females at heterozygous state. These females were selected to be inseminated with conventional rams and produced carriers' lambs with 66.7% males and 33.3% females. The prolific males will be kept in breeding centers to disseminate the fecundity mutation in commercial flocks. This approach facilitates the dissemination of fecundity genes and contributes to livelihood improvement in communities raising Barbarine sheep.

Population structure, genetic diversity and prolificacy in pishan red sheep under an extreme desert environment.

Extreme environmental conditions are a major challenge for livestock production. Changes in climate conditions, especially those that lead to extreme weather, can reduce livestock production. The screening of genes and molecular markers is of great significance to explore the genetic mechanism of sheep prolificacy traits in Taklimakan Desert environment. We selected healthy adult Pishan Red Sheep (PRS) and Qira Black Sheep (QR) which live in Taklimakan Desert environment, collected blood from jugular vein, extracted DNA, and prepared Illumina Ovine SNP50 chip. For PRS, linkage disequilibrium (LD) was calculated using the ovine SNP50 Beadchip and the effective population size (Ne) was estimated using SMC++. The genetic characteristics of PRS were analyzed by integrated haplotype score (iHS) and fixation index (F ST ). The result showed that r 2 of PRS was 0.233 ± 0.280 in the range of 0-10Kb and decreased with increasing distances. SMC++ tested that the Ne of PRS remained at 236.99 in recent generations. 184 genes were screened out under iHS 1% threshold, and 1148 genes were screened out with F ST under the 5% threshold, and 29 genes were obtained from the intersection of the two gene sets. In this study, the genetic characteristics of PRS and QR were compared by ovine genome chip, and the related excellent genes were searched, providing reference for the protection of sheep germplasm resources and molecular breeding in a desert environment.

Are early-life lambs’ characteristics and behavioural reactivity related to later survival and growth performance during artificial feeding?

The use of prolific sheep breeds often leads farmers to rear some lambs with an automatic milk feeder to improve survival and growth. However, the success of these challenging situations could depend on lamb’s early individual characteristics, and their behavioural reactivity in a stressful context. The study was performed on 567 Romane lambs. We tested the hypothesis that early-life characteristics, including behaviour and physiology, could predict survival and growth performances until weaning. In addition, on a random subsample of one third of these lambs we assessed whether behavioural reactivity to social isolation and unknown human presence was a further predictor of individual variability in growth rate. Lambs were characterised by birth weight, rectal temperature and scores for vigour, handling and sucking of first bottle milk on arrival at nursing. After three weeks of artificial rearing (i.e. halfway to weaning age), 202 randomly-chosen lambs were studied in a 2-phase test to record their reaction to social isolation in a novel arena test and presence of an unknown human. Test variables were summarised phase-wise by principal component analysis. The factor scores characterised lamb general activity in phase 1 and affinity to humans in phase 2. Data was examined using descriptive statistics, survival analysis and multivariate regression models to identify the key factors for survival and average daily gain (ADG) until weaning. Cumulative early death rate at one week was 5% and global death rate at the end of the rearing period was 11.6%. There was a higher hazard ratio for death for weak sucking at the first milk-bottle test (P = 0.011), low rectal temperature (P < 0.05), and dam age of 4–5 years versus 2–3 years (P < 0.01). A low ADG until weaning was associated with a low vigour score (P < 0.01), weak sucking (P < 0.05) and low birth weight (P < 0.001). Our data also supports the hypothesis of a relationship between growth and behavioural reactivity in artificially-reared lambs. A low growth rate until weaning was also associated with higher lamb affinity shown to humans (P < 0.001) and lower activity expressed in social isolation in a new arena (P < 0.05). Our study suggests that early-age characteristics but also reactivity to social isolation and affinity to humans could be valuable predictors of lamb survival and growth in artificial rearing. Our results possibly reveal an over-dependency on humans in some lambs in such a system.

Gene expression pattern and molecular mechanisms involved in Shal and Sangsari sheep fertility using RNA-Seq.

Ovulation rate and litter size are the main reproductive traits with high economic value in the sheep breeding industry. In this study, three Shal ewes (multiparous) and three Sangsari ewes (uniparous) at the age of 5 were used. The live weight was between 45 and 50 kg at an extremely body condition score of 3. These breeds are marked seasonal reproduction activity and are often bred in semi-closed breeding systems. Total RNAs were extracted from the ovarian tissues, and RNA sequencing was carried out. The DAVID (Database for Annotation, Visualization and Integrated Discovery) database was then used to annotate genes, and the string database and the Cytoscape software were used to investigate their interactions. Then path-act network analysis and gene-act network analysis were investigated. The results indicated that 19,932 genes were differentially expressed. The 5968 differentially expressed genes were identified in Shal ewe's ovarian tissue compared to Sangsari ewes (FDR < 0.05), of which 2921 genes were up-regulated and 3047 genes were down-regulated. Bioinformatics analysis exhibited that most of the biological processes and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways associated with significant DEGs (Differentially Expressed Genes) in the two studied breeds are associated with oocyte maturation and metabolism. MAPK signalling pathways and Ubiquitin-mediated proteolysis are the most important biological pathways associated with reproductive and fertility traits in the Shal breed. AKT3, MAPK8, MAPK9 and RELA genes are also important genes related to the fertility of multiparous sheep. Analysis of ovarian RNA-seq data identified that most of the differentially expressed genes were involved in various reproductive processes including folliculogenesis, ovulation, ovarian and embryonic development. The MAPK signalling pathway had the most interaction with other pathways, and the AKT3 gene could be a powerful candidate gene in the reproduction and fertility of Shal sheep. These results could pave the way for future efforts to address sheep prolificacy barriers.

Prolific Avishaan Sheep Toward Doubling the Farmer Income: A Review

The main objective of the study is to increase the meat production by rearing of Avishaan sheep. Avishaan sheep is a prolific sheep which is developed through crossing of three indigenous sheep breed (Garole, Malpura and Patanwadi). Avishaan sheep produce more number of lambs due to presence of FecB gene, inherited from microsheep Garole of West Bengal state of India. Avishaan sheep has better reproductive efficiency and litter size as compared to non-prolific Indian sheep breeds. Avishaan sheep has higher litter size, more litter weight and sufficient milk for their neonates. Therefore, it will be boon for farmers toward doubling the income by selling additional lambs received due to prolificacy trait inheritance. At commercial level, under intensive system, Avishaan sheep farming is most suitable for maximum profit. In future, due to declining natural resources, Avishaan sheep will fulfill the increasing meat demand of the nation.