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By analyzing the expression patterns of inner root sheath (IRS) specific genes during different developmental stages of hair follicle (HF) in Tan sheep embryos and at birth, this study aims to reveal the influence of the IRS on crimped wool. Skin tissues from the scapular region of male Tan sheep were collected at 85 days (E85) and 120 days (E120) of fetal development, and at 0 days (D0), 35 days (D35), and 60 days (D60) after birth, with four samples at each stage. Real-time quantitative polymerase chain reaction (RT-qPCR) was employed to determine the relative expression levels of IRS type I keratin genes (KRT25, KRT26, KRT27, KRT28), type II keratin genes (KRT71, KRT72, KRT73, KRT74), and the trichohyalin gene (TCHH) in the skin of Tan sheep at different stages. Results showed that the expression levels of all IRS-specific genes peaked at D0, with the expression of all genes significantly higher than at E85 (P < 0.01), except for KRT73 and TCHH. The expression levels of KRT25, KRT26, and KRT72 were also significantly higher than at E120 (P < 0.01). Furthermore, the expression levels of KRT27, KRT28, KRT71, and KRT74 were significantly higher than both at E120 and D35 (P < 0.01). The expression levels of other genes at different stages showed no significant difference (P > 0.05). Conclusion: The IRS-specific genes exhibit the highest expression levels in Tan sheep at the neonatal stage. The expression levels of KRT71, KRT72, and TCHH, which are consistent with the pattern of wool crimp, may influence the morphology of the IRS and thereby affect the crimp of Tan sheep wool., Competing Interests: Declaration of competing interest 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., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The development of wool has a complex regulatory mechanism both influenced by genetic and environmental factors. MicroRNAs (miRNA) were involved in various biological processes of animals, and may play an important role in the regulation of wool development. In this study, we comprehensively analyzed and identified the histological parameters of hair follicles, as well as the miRNAs, target genes, pathways, and Gene Ontology terms related to wool fineness regulation and wool growth and development using HE staining and RNA-Seqs methods. Both coarse (group C, mean fiber diameter (MFD) = 22.26 ± 0.69 μm, n = 6) and fine (group F, MFD = 16.91 ± 0.29 μm, n = 6) of Gansu alpine fine-wool sheep with different wool fineness were used in this study. The results showed that the primary follicle diameter and secondary wool fiber diameter in group C were significantly higher than those in group F (P < 0.05). And the number of primary and secondary hair follicles in group C was significantly lower than that in group F (P < 0.05). Furthermore, a total of 67 DE miRNAs and 290 potential DE miRNAs target genes were screened in the skin tissues of sheep from groups F and C, and some potential target genes related to wool fineness regulation were screened, such as CDH2, KRT82, FOXN1, LOC101106296, KRT20, MCOLN3, KRT71, and TERT. These genes were closely related to Glutathione metabolism, epidermal cell differentiation, keratinization, and regulation of hair cycle. Moreover, the regulatory network of miRNAs-mRNAs suggested that miRNAs (miR-129-x, novel m0079-3p, miR-2484-z, novel m0025-5P, etc.) may play a key role in the wool development and wool fineness regulation of Gansu alpine fine-wool sheep. In summary, this study expands the existing miRNAs database and provides new information for studying the regulation of wool development in Gansu alpine fine wool sheep., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

The purpose of this work is to produce keratin hydrolysate from sheep wool by alkaline hydrolysis and to assess its effectiveness in improving maize plant growth under greenhouse conditions. A hybrid response surface methodology with Box-Behnken design (RSM-BBD) was used to model and optimize the hydrolysis process. The synergistic effects between three critical independent variables including temperature, hydrolysis time, and concentration of KOH on the hydrolysis rate were statistically investigated and optimized. Under optimized conditions, a hydrolysis rate of 95.08% was achieved. The produced hydrolysate consists of water-soluble peptides, free amino acids and potassium ions, making it suitable to be used as a valuable agricultural input material for crop production. Amino acid analysis revealed high levels of proline and phenylalanine, which are responsible for water conditioning and the preservation of abiotic stress as readily available. The efficacy of the produced hydrolysate was assessed in the cultivation of maize as a crop model under greenhouse conditions. Results revealed that the application of the hydrolysate positively influenced the morphological traits of the maize crop such as plant height and leaf surface area. The magnitude of the response to the hydrolysate application depended on its concentration with the most positive effects observed at a dose 2 for the leaf's chlorophyll content, fresh shoot biomass and dry shoot biomass. The application of the hydrolysate improved fresh and dry shoot biomass by 32.5 and 34.4% compared to the control and contributed to the improvement of nitrogen use efficiency by the studied crop. The hydrolysate proved to be beneficial in improving overall plant growth and can be suitable and effective agricultural input for maize cultivation., Competing Interests: Declaration of competing interest The authors declare no competing financial interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: The Alpine Merino is a new breed of fine-wool sheep adapted to the cold and arid climate of the plateau in the world. It has been popularized in Northwest China due to its superior adaptability as well as excellent production performance. Those traits related to body weight, wool yield, and wool fiber characteristics, which are economically essential traits in Alpine Merino sheep, are controlled by QTL (Quantitative Trait Loci). Therefore, the identification of QTL and genetic markers for these key economic traits is a critical step in establishing a MAS (Marker-Assisted Selection) breeding program., Results: In this study, we constructed the high-density genetic linkage map of Alpine Merino sheep by sequencing 110 F 1 generation individuals using WGR (Whole Genome Resequencing) technology. 14,942 SNPs (Single Nucleotide Polymorphism) were identified and genotyped. The map spanned 2,697.86 cM, with an average genetic marker interval of 1.44 cM. A total of 1,871 high-quality SNP markers were distributed across 27 linkage groups, with an average of 69 markers per LG (Linkage Group). Among them, the smallest genetic distance is 19.62 cM for LG2, while the largest is 237.19 cM for LG19. The average genetic distance between markers in LGs ranged from 0.24 cM (LG2) to 3.57 cM (LG17). The marker density in the LGs ranged from LG14 (39 markers) to LG1 (150 markers)., Conclusions: The first genetic map of Alpine Merino sheep we constructed included 14,942 SNPs, while 46 QTLs associated with body weight, wool yield and wool fiber traits were identified, laying the foundation for genetic studies and molecular marker-assisted breeding. Notably, there were QTL intervals for overlapping traits on LG4 and LG8, providing potential opportunities for multi-trait co-breeding and further theoretical support for selection and breeding of ultra-fine and meaty Alpine Merino sheep., (© 2024. The Author(s).)

The native Spanish Merino breed was the founder of all the other Merino and Merino-derived breeds worldwide. Despite the fact that this breed was created and improved to produce the highest quality fine wool, the global wool market crisis led to the wholescale crossing of most of the herds with breeds for meat purposes. Nevertheless, there are still some purebred animals with a high potential for producing quality wool. The objective of this study was to characterize the current wool quality of the breed and identify genes associated with these parameters. To achieve this, over 12,800 records from the most representative animals of the breed (registered in the herd book) were analyzed using the Australian OFDA 2000 system, for parameters such as fiber diameter (FD), standard deviation (SD), coefficient of variation (CV), fibers over 15 microns (>15%), staple length (SL), and comfort factor (CRV). Additionally, animals with the most extreme FD values were whole-genome sequenced using NGS. Genome-wide association studies (GWAS) determined the association of 74 variants with the different traits studied, which were located in 70 different genes. Of these genes, EDN2 , COL18A1 , and LRP1B, associated with fibers over 15%, and FGF12 and ADAM17 , associated with SL, play a key role in hair follicle growth and development. Our study reveals the great potential for recovering this breed for fine wool production, and identifies five candidate genes whose understanding may aid in that selection process.

Keratins are the main structural protein components of wool fibres, and variation in them and their genes ( KRTs ) is thought to influence wool structure and characteristics. The PCR-single strand conformation polymorphism technique has been used previously to investigate genetic variation in selected coding and intron regions of the type II sheep keratin gene KRT81 , but no variation was identified. In this study, we used the same technique to explore the 5' untranslated region of KRT81 and detected three sequence variants ( A , B and C ) that contain four single nucleotide polymorphisms. Among the 389 Merino × Southdown cross sheep investigated, variant B was linked to a reduction in clean fleece weight, while C was associated with an increase in both greasy fleece weight and clean fleece weight. No discernible effects on staple length or mean-fibre-diameter-related traits were observed. These findings suggest that variation in ovine KRT81 might influence wool growth by changing the density of wool follicles in the skin, the density of individual fibres, or the area of the skin producing fibre, as opposed to changing the rate of extrusion of fibres or their diameter.

Hair follicle development and wool shedding in sheep are poorly understood. This study investigated the population structures and genetic differences between sheep with different wool types to identify candidate genes related to these traits. We used Illumina ovine SNP 50K chip genotyping data of 795 sheep populations comprising 27 breeds with two wool types, measuring the population differentiation index (Fst), nucleotide diversity (θπ ratio), and extended haplotype homozygosity among populations (XP-EHH) to detect the selective signatures of hair sheep and fine-wool sheep. The top 5% of the Fst and θπ ratio values, and values of XP-EHH < -2 were considered strongly selected SNP sites. Annotation showed that the PRX , SOX18 , TGM3 , and TCF3 genes related to hair follicle development and wool shedding were strongly selected. Our results indicated that these methods identified important genes related to hair follicle formation, epidermal differentiation, and hair follicle stem cell development, and provide a meaningful reference for further study on the molecular mechanisms of economically important traits in sheep.

Sheep operations will be subject to movement controls during a US foot and mouth disease outbreak and should be prepared to manage animal and product movement disruptions. The voluntary Secure Sheep and Wool Supply (SSWS) Plan for Continuity of Business provides tools for the sheep industry to develop contingency plans, write enhanced, operation-specific biosecurity plans, and learn about disease surveillance opportunities and challenges. The SSWS Plan is science-based and risk-based, funded by the American Sheep Industry Association, and developed collaboratively with industry, government officials, and veterinarians at Iowa State University. For more information, visit www.securesheepwool.org., Competing Interests: Disclosure D.A. Bickett-Weddle: The author works for the Center for Food Security and Public Health (CFSPH) at Iowa State University, which received funding from the American Sheep Industry (ASI) Association to develop the Secure Sheep and Wool Supply (SSWS) Plan for Continuity of Business (COB), supporting documents, and Web site. The CFSPH also received funding from USDA APHIS for the maintenance of the Secure Beef and Milk Supply Plans, supporting documents, and Web site. R.D. Dewell: The author works for the CFSPH at Iowa State University, which received funding from the ASI Association to develop the SSWS Plan for COB, supporting documents, and Web site. The CFSPH also received funding from USDA APHIS for the maintenance of the Secure Beef and Milk Supply Plans, supporting documents, and Website. C.E. McIntosh: The author works for the CFSPH at Iowa State University, which received funding from the ASI Association to develop the SSWS Plan for COB, supporting documents, and Web site. The CFSPH also received funding from USDA APHIS for the maintenance of the Secure Beef and Milk Supply Plans, supporting documents, and Web site., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Wild sheep and many primitive domesticated breeds have two coats: coarse hairs covering shorter, finer fibres. Both are shed annually. Exploitation of wool for apparel in the Bronze Age encouraged breeding for denser fleeces and continuously growing white fibres. The Merino is regarded as the culmination of this process. Archaeological discoveries, ancient images and parchment records portray this as an evolutionary progression, spanning millennia. However, examination of the fleeces from feral, two-coated and woolled sheep has revealed a ready facility of the follicle population to change from shedding to continuous growth and to revert from domesticated to primitive states. Modifications to coat structure, colour and composition have occurred in timeframes and to sheep population sizes that exclude the likelihood of variations arising from mutations and natural selection. The features are characteristic of the domestication phenotype: an assemblage of developmental, physiological, skeletal and hormonal modifications common to a wide variety of species under human control. The phenotypic similarities appeared to result from an accumulation of cryptic genetic changes early during vertebrate evolution. Because they did not affect fitness in the wild, the mutations were protected from adverse selection, becoming apparent only after exposure to a domestic environment. The neural crest, a transient embryonic cell population unique to vertebrates, has been implicated in the manifestations of the domesticated phenotype. This hypothesis is discussed with reference to the development of the wool follicle population and the particular roles of Notch pathway genes, culminating in the specific cell interactions that typify follicle initiation.

Background: Aohan fine wool sheep (AFWS) is a historically bred fine wool sheep, cultivated in China. The wool has excellent quality and good textile performance. Investigating the molecular mechanisms that regulate wool growth is important to improve wool quality and yield. Circular RNAs (circRNAs) are widely expressed non-coding RNAs that can act as competitive endogenous RNAs (ceRNAs) to bind to miRNAs. Although circRNAs have been studied in many fields, research on their activity in sheep wool follicles is limited. To understand the regulation of circRNAs in the growth of fine wool in sheep, we used RNA-Seq to identify circRNAs in sheep shoulder skin samples at three developmental stages: embryonic day 90 (E90d), embryonic day 120 (E120d), and at birth (Birth)., Results: We identified 8753 circRNAs and found that 918 were differentially-expressed. We then analyzed the classification and characteristic of the circRNAs in sheep shoulder skin. Using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), we identified the source genes of circRNAs, which were mainly enriched in cellular component organization, regulation of primary metabolic processes, tight junctions, and the cGMP-PKG and AMPK signaling pathways. In addition, we predicted interactions between 17 circRNAs and eight miRNAs, using miRanda software. Based on the significant pathways, we speculate that circ&#95;0005720, circ&#95;0001754, circ&#95;0008036, circ&#95;0004032, circ&#95;0005174, circ&#95;0005519, and circ&#95;0007826 might play an important role in regulating wool follicle growth in AFWS. Seven circRNAs were randomly selected to validate the RNA-Seq results, using qRT-PCR., Conclusion: Our results provide more information about circRNAs regulation of wool follicle development in AFWS, and establish a solid foundation for future research.

The keratin-associated proteins (KAPs) are structural components of wool fibers and variation in the genes encoding the KAPs can affect wool traits. In this study, sequence variation in the ovine KAP7-1 gene (KRTAP7-1) was investigated in 222 sheep across 5 different Pakistani breeds and breed crosses. Two previously identified variants (A and B) of the KRTAP7-1 coding sequence were identified. The frequency of the genotypes AA and AB was 76% and 23%, respectively, and that of BB was 1%. The association of sequence variation with various wool traits and measurements included yield (the proportion of greasy fleece weight that is clean fleece), mean staple length (MSL), wool bulk, mean fiber diameter, fiber diameter SD, the coefficient of variation of fiber diameter, medullation, the SD of medullation, the coefficient of variation of medullation, fiber opacity, the SD of opacity, and the coefficient of variation of opacity. Variation in KRTAP7-1 was found to be associated with yield (P = 0.017). The adjusted mean yield of sheep of genotype AA (n = 169) was 79.9 ± 2.72%, while that of genotype AB (n = 51) was 81.9 ± 3.37%. There was also an association between variation in KRTAP7-1 and MSL (P = 0.024), with sheep of genotype AA (n = 169) having an adjusted mean MSL of 47.3 ± 0.57 mm compared with sheep of genotype AB (n = 51, 50.9 ± 0.65 mm). Yield and MSL are both important wool production traits, hence variation in KRTAP7-1 needs to be further investigated in more sheep of differing breed., (© The Author(s) 2019. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The correlations between growth and wool traits in response to canola and flaxseed oil supplementation were evaluated in Australian prime lambs. Sixty dual-purpose prime lambs including purebred Merino and crossbred lambs were allocated to one of five treatments of lucerne hay basal diet supplemented with isocaloric and isonitrogenous wheat-based pellets. Treatments were: no oil inclusion (Control); 2.5% canola oil; 5% canola oil; 2.5% flaxseed oil and 5% flaxseed oil, with lamb groups balanced by breed and gender. Each lamb was daily supplemented with 1kg of pellets and had free access to lucerne hay and water throughout the 7-week feeding trial, after a 3-week adaptation. Individual animal basal and supplementary pellet feed intakes were recorded daily, while body conformation traits, body condition scores and liveweights were measured on days 0, 21, 35 and 49. The lambs were dye-banded on the mid-side and shorn before commencing the feeding trial and mid-side wool samples were collected from the same dye-banded area of each lamb at the end of the experiment. Correlations between wool quality traits and lamb performance were non-significant (P>0.05). Oil supplementation had no detrimental effect on lamb growth and wool quality traits (P > 0.05). Gender significantly affected wither height gain and fibre diameter. There were significant interactions between oil supplementation and lamb breed on chest girth. The correlations between clean fleece yield (CFY) and other wool quality traits were moderate ranging from 0.29 to 0.55. Moderate to high correlations between fibre diameter (FD) and other wool quality traits were detected (0.46-0.99) with the strongest relationship between FD and wool spinning fineness (SF). The relationship between CFY and wool comfort factor (CF) were positive, while negative relationships between CFY and the others were observed. A combination of 5% oil supplementation and genetics is an effective and strategic management tool for enhancing feed efficiency and growth performance without negative effects on wool quality in dual-purpose lamb production. This is a good outcome for dual-purpose sheep farmers. It essentially means the absorbed nutrients in supplemented lambs yielded good growth performance without any detrimental impact on wool quality; a win-win case of nutrient partitioning into the synthesis of muscle and wool without compromising either traits., Competing Interests: The authors have declared that no competing interests exist.

Rabbit fur characteristics are primarily genetically determined traits. We used Illumina high-throughput sequencing technology to assess gene expression in the skin tissues of rabbits derived from a cross between Wanxi Angora rabbits and Rex rabbits, which exhibit differential characteristics of short and long wool respectively, to investigate molecular mechanisms related to wool length determination. To identify key regulatory genes involved in rabbit wool length, genes that were differentially expressed between the long- and short-wool rabbits based on a P-value < 0.05 and log 2 |fold change| > 1 were characterized. A total of 798 genes were up-regulated and 523 were down-regulated in the long-wool group compared to expression levels in the short-wool group, and these genes were annotated with GO terms and KEGG pathways, revealing wool-development-related biological functions. The Wnt, Hedgehog and TGF-β signaling pathways, which are related to cell proliferation, fibroblast proliferation and hair follicle regulation respectively, were identified. The expression levels of eight genes were validated by RT-qPCR. In addition, an interaction network was constructed to show the regulatory relationships among the differentially expressed genes. In this study, we found that FGF5, WNT5A, BMP4 and BMP7 showed significant differential expression between the two groups. These transcriptomic profiling results provide comprehensive gene expression information for improving understanding of the molecular mechanisms involved in the growth and development of rabbit wool., (© 2018 Stichting International Foundation for Animal Genetics.)

The structural component of wool and hair fibers, such as keratin-associated proteins (KAPs), has been well described, but the genetic determinants of fiber diameter are largely unknown. Here, we have used an iTRAQ-based proteomic approach to investigate differences in protein abundance among 18 samples from sheep and goats across a diverse range of fibers. We identified proteins with different abundance and are associated with variation in fiber features. Proteins with different abundance are mainly keratin or keratin-associated proteins (KRTAP11-1, KRT6A, KRT38), or are related to hair growth (DSC2, DSG3, EEF2, CALML5, TCHH, SELENBP1) and fatty acid synthesis (FABP4, FABP5). RNA-seq further confirmed the functional importance of the DSC2 gene in the determination of woolly phenotype in goat fibers. This comprehensive analysis of fibers from major fiber-producing animals is the first to provide a list of candidate proteins that are involved in fiber formation. This list will be valuable asset for future studies into the molecular mechanisms that underlie fiber diversity., Biological Significance: Proteins are the basis for animal-derived hair fibers, yet proteins conferring fiber structure and characteristics in sheep and goats are largely elusive. By examining 27 fibers samples representing 9 fiber types from sheep and goats through the iTRAQ approach, we show a list of differentially abundant proteins that are important to hair structural component, or genes related to hair growth and fatty acid synthesis. RNA-seq further validated the DSC2 gene is key to the woolly/straight hair phenotype in goats., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The anagen phase of the hair follicle cycle is when the follicle is configured to grow hair. In short hairs (e.g., mouse underhairs and human eye lashes) anagen phase is short, but in the wool of sheep and in human scalp hair anagen is a prolonged state lasting for years. In this chapter we describe the morphological and biological divisions within the anagen follicle.

Fur is an important economic trait in rabbits. The identification of genes that influence fur development and knowledge regarding the actions of these genes provides useful tools for improving fur quality. However, the mechanism of fur development is unclear. To obtain candidate genes related to fur development, the transcriptomes of tissues from backs and bellies of Chinchilla rex rabbits were compared. Of the genes analyzed, 336 showed altered expression in the two groups (285 upregulated and 51 downregulated, P ≤ 0.05, fold-change ≥2 or ≤0.5). Using GO and KEGG to obtain gene classes that were differentially enriched, we found several genes to be involved in many important biological processes. In addition, we identified several signaling pathways involved in fur development, including the Wnt and MAPK signaling pathways, revealing mechanisms of skin and hair follicle development, and epidermal cell and keratinocytes differentiation. The obtained rabbit transcriptome and differentially expressed gene profiling data provided comprehensive gene expression information for SFRP2, FRZB, CACNG1, SLC25A4, and SLC16A3. To validate the RNA-seq data, the expression levels of eight differentially expressed genes involved in fur development were confirmed by qRT-PCR. The results of rabbit transcriptomic profiling provide a basis for understanding the molecular mechanisms of fur development.

Fibroblast growth factor 5 (FGF5) has been recognized as an inhibitor to cease animal hair growth, while in contrary, FGF5 short alternative transcript (FGF5s) can induce hair growth by antagonizing FGF5 function. To investigate the role of FGF5s in wool growth in Chinese Merino sheep, we generated transgenic sheep of ectopic expression of FGF5s by injection of recombinant lentivirus into zygote. Totally 20 transgenic sheep were obtained and 12 were alive after birth. Characterization of the transgene revealed that the transgenic sheep showed variety of integrant, ranged from 2 to 11 copies of transgene. The ectopic expression of FGF5s was observed in all transgenic sheep. Further study on the effect of ectopic expression of FGF5s revealed that the wool length of transgenic sheep were significantly longer than that of non-transgenic control, with 9.17cm of transgenic lambs versus 7.58cm of control animals. Notably, besides the increase of wool length, the yearling greasy fleece weight was also concordantly greater than that of wild-type (p<0.01), with 3.22kg of transgenic sheep versus 2.17kg of control lambs (p<0.01) in average. Our results suggested that overexpression of FGF5s could stimulate wool growth and resulted in increase of wool length and greasy wool weight., (Copyright © 2017. Published by Elsevier B.V.)

Fibroblast growth factor 5 (FGF5) regulates hair length in humans and a variety of other animals. To investigate whether FGF5 has similar effects in sheep, we used clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated 9 (Cas9) to generate loss-of-function mutations with the FGF5 gene in Chinese Merino sheep. A total of 16 lambs were identified with genetic mutations within the targeting locus: 13 lambs had biallelic modifications and three lambs had monoallelic modifications. Characterization of the modifications revealed that 13 were frameshift mutations that led to premature termination, whereas the other three were in-frame deletions. Thus, CRISPR/Cas9 efficiently generated loss-of-function mutations in the sheep FGF5 gene. We then investigated the effect of loss of FGF5 function on wool traits in 12 lambs and found that wool staple length and stretched length of genetically modified (GM) yearling sheep were significantly longer compared with that of wild-type (WT) control animals. The greasy fleece weight of GM yearling sheep was also significantly greater compared with that of WT sheep. Moreover, the mean fiber diameter in GM sheep showed no significant difference compared with WT sheep, suggesting that the increase in greasy fleece weight was likely attributed to the increase in wool length. The results of this study suggest that CRISPR/Cas9-mediated loss of FGF5 activity could promote wool growth and, consequently, increase wool length and yield., (© 2017 The Authors. The FEBS Journal published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.)

Genetic correlations between 29 wool production and quality traits and 14 whole carcass measures and carcass component traits were estimated from the Information Nucleus of 8 flocks managed across a range of Australian sheep production environments and genetically linked. Wool data were from over 5,000 Merino progeny born over 5 yr, whereas carcass data were from over 1,200 wether progeny of over 176 sires, slaughtered at about 21 kg carcass weight, on average. Wool traits included yearling and adult records for wool weight, fiber diameter, fiber diameter variation, staple strength, scoured color, and visual scores for breech and body wrinkle. Whole carcass measures included HCW, dressing percentage (DP), and various measures of fat depth and eye muscle dimensions. Carcass components were obtained by dissection, and lean meat yield (LMY) was predicted. Heritability estimates for whole carcass measures ranged from 0.12 ± 0.08 to 0.35 ± 0.10 and ranged from 0.17 ± 0.10 to 0.46 ± 0.10 for carcass dissection traits, with no evidence of important genotype × environment interactions. Genetic correlations indicated that selection for increased clean wool weight will result in reduced carcass fat (-0.17 to -0.34) and DP (-0.48 ± 0.15), with little effect on carcass muscle. Selection for lower fiber diameter will reduce HCW (-0.48 ± 0.15) as well as carcass fat (0.14 to 0.27) and muscle (0.21 to 0.50). There were high genetic correlations between live animal measures of fat and muscle depth and the carcass traits (generally greater than 0.5 in size). Selection to increase HCW (and DP) will result in sheep with fewer wrinkles on the body (-0.57 ± 0.10) and barer breeches (-0.74 ± 0.12, favorable), with minor deterioration in scoured wool color (reduced brightness and increased yellowness). Selection for reduced fat will also result in sheep with fewer body wrinkles (-0.42 to -0.79). Increasing LMY in Merinos through selection would result in a large reduction in carcass fat and DP (-0.66 to -0.84), with a smaller increase in carcass muscle and some increase in wool weight and wrinkles. Although no major antagonisms are apparent between the wool and carcass traits, developing selection indexes for dual-purpose wool and meat breeding objectives will require accurate estimates of genetic parameters to ensure that unfavorable relationships are suitably considered. The findings will aid development of dual-purpose wool and meat breeding objectives.

Sheep are an important source of fiber production. Fibroblast growth factor 5 (FGF5) is a dominant inhibitor of length of the anagen phase of the hair cycle. Knockout or silencing of the gene results in a wooly coat in mice, donkeys, dogs, and rabbits. In sheep breeding, wool length is one of the most important wool quality traits. However, traditional breeding cannot accurately and efficiently mediate an advanced genotype into the sheep genome. In this study, we generated 3 knockout sheep via the 1-step clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9 system. Sequencing analysis confirmed that mutations in the gene existed in all germ lines of 3 founders: besides the intact sequence, 3 kinds of deletions in the gene (including 5, 13, and 33 bp) were detected. The changes in the primary and senior structure of the FGF5 protein due to the 3 deletions in founders suggested that the FGF5 protein was dysfunctional. In addition, the expression level of intact mRNA in heterozygous individuals decreased compared with the wild types ( < 0.01). Functionally, we discovered that wool length in founders was significantly longer than in wild types ( < 0.05). Collectively, the knockout sheep with the longer wool length phenotype will provide an efficient way for fast genetic improvement of sheep breeding and promote the development of wool industry.

Genetic correlations between 29 wool production and quality traits and live weight and ultrasound fat depth (FAT) and eye muscle depth (EMD) traits were estimated from the Information Nucleus (IN). The IN comprised 8 genetically linked flocks managed across a range of Australian sheep production environments. The data were from a maximum of 9,135 progeny born over 5 yr from 184 Merino sires and 4,614 Merino dams. The wool traits included records for yearling and adult fleece weight, fiber diameter (FD), staple length (SL), fiber diameter CV (FDCV), scoured color, and visual scores for breech and body wrinkle. We found high heritability for the major yearling wool production traits and some wool quality traits, whereas other wool quality traits, wool color, and visual traits were moderately heritable. The estimates of heritability for live weight generally increased with age as maternal effects declined. Estimates of heritability for the ultrasound traits were also higher when measured at yearling age rather than at postweaning age. The genetic correlations for fleece weight with live weights were positive (favorable) and moderate (approximately 0.5 ± 0.1), whereas those with FD were approximately 0.3 (unfavorable). The other wool traits had lower genetic correlations with the live weights. The genetic correlations for FAT and EMD with FD and SL were positive and low, with FDCV low to moderate negative, but variable with wool weight and negligible for the other wool traits. The genetic correlations for FAT and EMD with postweaning weight were positive and high (0.61 ± 0.18 to 0.75 ± 0.14) but were generally moderate with weights at other ages. Selection for increased live weight will result in a moderate correlated increase in wool weight as well as favorable reductions in breech cover and wrinkle, along with some unfavorable increases in FD and wool yellowness but little impact on other wool traits. The ultrasound meat traits, FAT and EMD, were highly positively genetically correlated (0.8), and selection to increase them would result in a small unfavorable correlated increase in FD, moderately favorable reductions in breech cover and wrinkle, but equivocal or negligible changes in other wool traits. The estimated parameters provide the basis for calculation of more accurate Australian Sheep Breeding Values and selection indexes that combine wool and meat objectives in Merino breeding programs.

Identifying genes of major effect for wool growth would offer strategies for improving the quality and increasing the yield of fine wool. In this study, we employed the Agilent Sheep Gene Expression Microarray and proteomic technology to investigate the gene expression patterns of body side skin (more wool growing) in Aohan fine wool sheep (a Chinese indigenous breed) in comparison with groin skin (no wool growing) at the anagen stage of the wool follicle. A microarray study revealed that 4772 probes were differentially expressed, including 2071 upregulated and 2701 downregulated probes, in the comparisons of body side skin vs. groin skin (S/G). The microarray results were verified by means of quantitative PCR. A total of 1099 probes were assigned to unique genes/transcripts. The number of distinct genes/transcripts (annotated) was 926, of which 352 were upregulated and 574 were downregulated. In S/G, 13 genes were upregulated by more than 10 fold, whereas 60 genes were downregulated by more than 10 fold. Further analysis revealed that the majority of the genes possibly related to the wool growth could be assigned to categories including regulation of cell division, intermediate filament, cytoskeletal part and growth factor activity. Several potential gene families may participate in hair growth regulation, including fibroblast growth factors, transforming growth factor-β, WNTs, insulin-like growth factor, vascular endothelial growth factors and so on. Proteomic analysis also revealed 196 differentially expressed protein points, of which 121 were identified as single protein points., (© 2016 Stichting International Foundation for Animal Genetics.)

Crossbreeding of Australian Superfine Merinos (ASMs) with Gansu Alpine Finewool (GAF) sheep and an evaluation of the potential benefits of this genetic cross has not been previously conducted. 13 ASMs were crossbred with GAF sheep over a five year period with backcrossing designed to assess heterosis. Data from 11,178 lambs sired by 189 rams were used in the study. Genotype, birth year, birth type, dam age, sex and/or management group, and record age were fitted as fixed effects and within-genotype sire fitted as a random effect. Crossbreeds of 1/2 ASM expressed the most desirable effects for improving average fiber diameter (AFD), clean fleece weight (CFW), yield, coefficient of variation of AFD (CVAFD), yearling staple length (YSL) to AFD ratio (YSL/AFD), and CFW to metabolic yearling bodyweight (YWT0.75) ratio (CFW/YWT0.75) but showed the least post-weaning average daily gain (powADG) and YWT. Genotype of backcrossing with 1/4 ASM obtained moderate improvements in AFD, CFW, CVAFD, and YSL/AFD but the highest YSL, WWT, and prwADG. Except for yield (-1.42%) and CFW/YWT0.75 (-1%), heterosis estimates were generally low and positive, and ranged from 0.1% for CVAFD to 4% for powADG, which indicates the potential to improve relevant traits through exploiting heterosis to a varying extent. The ASMs sampled in this study were found to be superior to GAFs for AFD, CFW, yield, and CVAFD by 19.82%, 11.68%, 14.47%, and 6.99%, respectively, but inferior for YSL, PowADG, and YWT by 4.36%, 50.97%, and 16.93%, respectively. ASMs also appeared to be more efficient than GAFs in clean wool production (25.34%) and staple length growth (16.17%). The results of our study strongly suggest that an infusion of ASM genes via crossbreeding is an effective and appropriate approach to improve wool microns and wool production from GAF sheep, and we make recommendations to tackle the undesirable traits of YWT and YSL from ASM introduction., Competing Interests: The authors have declared that no competing interests exist.

The effect of the Developmental Origins of Health and Disease on the spread of non-communicable diseases is recognised by world agencies such as the United Nations and the World Health Organization. Early environmental effects on offspring phenotype also apply to domestic animals and their production traits. Herein, we show that maternal nutrition not only throughout pregnancy, but also in the periconception period can affect offspring phenotype through modifications of gametes, embryos and placental function. Because epigenetic mechanisms are key processes in mediating these effects, we propose that the study of epigenetic marks in gametes may provide additional information for domestic animal selection.

MicroRNAs are very small endogenous RNA molecules that play a crucial role in an array of biological processes, including regulation of skin morphogenesis. The microRNA let-7b is thought to modulate animal hair growth, by binding target genes that encode growth factors. Fibroblast growth factor 5 (FGF5) has been previously reported to be involved in the initiation of the catagen phase of hair growth. In this study, we combined previous reports with bioinformatic analysis techniques to identify and validate FGF5 and, using lucerifase assay, confirmed targeted binding of let-7b to FGF5. To investigate the interaction between let-7b and FGF5, alpaca skin fibroblasts were transfected with let-7b over-expression vectors, and then mRNA and protein expression levels of FGF5 and the gene encoding its receptor, FGFR1, were evaluated. Levels of FGF5 mRNA and protein were remarkably lower in transfected groups, as compared to controls. In summary, this study confirmed that let-7b acts as a regulator of skin morphogenesis, by directly targeting FGF5 and down-regulating its expression. It provides the evidence of hair growth regulated by miRNAs in animals and may have important applications in wool production.

Background: Gastrointestinal nematode (GIN) infections are common in domestic sheep and impact directly and indirectly on the health of infected animals as well as on the associated economic production. In this study, we aim at summarizing the current knowledge on the influence of GIN infections on sheep production by conducting a systematic review. A subsequent meta-analysis of relevant studies was performed to provide an estimate of the effect of GIN infections on weight gain, wool production and milk yield., Methods: A literature search was performed on the CAB, Pubmed and Web of Science database for the period 1960-2012. Inclusion criteria were: 1) Measurement of at least one production parameter. 2) Comparison between groups of sheep with different nematode burdens. 3) Same conditions regarding all aspects except parasite burden between groups. 4) Quantitative measurements of one or more production traits., Results: Altogether, 88 studies describing 218 trials were included in this review. The majority of studies (86%) reported that GIN infections had a negative effect on production but this was reported to be statistically significant in only 43% of the studies. Meta-analysis indicated that performances of sheep infected with nematodes was 85, 90 and 78% of the performance in uninfected individuals for weight gain, wool production and milk yield respectively. Our results suggest a possible reporting bias or small study effect for the estimation of the impact of GIN infections on weight gain. Finally, a general linear model provided an estimate for the decrease in weight gain in relation to the increase in faecal egg count of nematodes., Conclusion: This study underlines the importance of GIN infections for sheep production and highlights the need to improve parasite management in sheep, in particular in face of challenges such as anthelmintic resistance.

Methionine synthase (MTR) plays a crucial role in maintaining homeostasis of intracellular methionine, folate, and homocysteine, and its activity correlates with DNA methylation in many mammalian tissues. Our previous genomewide association study identified that 1 SNP located in the gene was associated with several wool production and quality traits in Chinese Merino. To confirm the potential involvement of the gene in sheep wool production and quality traits, we performed sheep tissue expression profiling, SNP detection, and association analysis with sheep wool production and quality traits. The semiquantitative reverse transcription PCR analysis showed that the gene was differentially expressed in skin from Merino and Kazak sheep. The sequencing analysis identified a total of 13 SNP in the gene from Chinese Merino sheep. Comparison of the allele frequencies revealed that these 13 identified SNP were significantly different among the 6 tested Chinese Merino strains ( < 0.001). Linkage disequilibrium analysis showed that SNP 3 to 11 were strongly linked in a single haplotype block in the tested population. Association analysis showed that SNP 2 to 11 were significantly associated with the average wool fiber diameter and the fineness SD and that SNP 4 to 11 were significantly associated with the CV of fiber diameter trait ( < 0.05). Single nucleotide polymorphism 2 and SNP 5 to 12 were weakly associated with wool crimp. Similarly, the haplotypes derived from these 13 identified SNP were also significantly associated with the average wool fiber diameter, fineness SD, and the CV of fiber diameter ( < 0.05). Our results suggest that is a candidate gene for sheep wool production and quality traits, and the identified SNP might be used in sheep breeding.

Ruminant methane yield (MY) is positively correlated with mean retention time (MRT) of digesta. The hormone triiodothyronine (T3 ), which is negatively correlated with ambient temperature, is known to influence MRT. It was hypothesised that exposing sheep to low ambient temperatures would increase plasma T3 concentration and decrease MRT of digesta within the rumen of sheep, resulting in a reduction of MY. To test this hypothesis, six Merino sheep were exposed to two different ambient temperatures (cold treatment, 9 ± 1 °C; warm control 26 ± 1 °C). The effects on MY, digesta MRT, plasma T3 concentration, CO2 production, DM intake, DM digestibility, change in body weight (BW), rumen volatile fatty acid (VFA) concentrations, estimated microbial protein output, protozoa abundance, wool growth, water intake, urine output and rectal temperature were studied. Cold treatment resulted in a reduction in MY (p < 0.01); digesta MRT in rumen (p < 0.01), hindgut (p = 0.01) and total digestive tract (p < 0.01); protozoa abundance (p < 0.05); and water intake (p < 0.001). Exposure to cold temperature increased plasma T3 concentration (p < 0.05), CO2 production (p = 0.01), total VFA concentrations (p = 0.03) and estimated microbial output from the rumen (p = 0.03). The rate of wool growth increased (p < 0.01) due to cold treatment, but DM intake, DM digestibility and BW change were not affected. The results suggest that exposure of sheep to cold ambient temperatures reduces digesta retention time in the gastrointestinal tract, leading to a reduction in enteric methane yield. Further research is warranted to determine whether T3 could be used as an indirect selection tool for genetic selection of low enteric methane-producing ruminants., (Journal of Animal Physiology and Animal Nutrition © 2014 Blackwell Verlag GmbH.)

This experiment was conducted to investigate the seasonal pattern of hair follicle activity, wool growth and fibre diameter (FD) in Sanjabi sheep in west Iran, Kermanshah (34° 18' N and 47° 3' E, elevation 1420 m). Ten male and 10 female Sanjabi sheep with an initial live weight of 32.1 ± 1.3 and 32.7 ± 1.5 (means ± SD), respectively, were used in a 365-day study. A diet was offered with an estimated concentration of 2.18 Mcal metabolizable energy and 130.0 g/kg DM crude protein. Body weight, average daily gain (ADG) and dry matter intake (DMI) were recorded weekly. The percentages of active primary and secondary wool follicles (PAP and PAS), follicle density and the ratio of secondary to primary follicles (S/P) were determined from skin biopsies, taken from the right mid-side of the sheep at monthly intervals. Raw and clean fibre growth rates and FD were measured from left mid-side patches (10 × 10 cm) harvested at the end of every month. There was a gradual increase in live weight throughout the experiment, while ADG and DMI changed in concert with day length. The greatest values for PAP and PAS were observed in summer, whereas lowest were obtained in winter (p < 0.001). Clean wool growth rate and FD were greatest (p < 0.001) in summer and lowest (p < 0.001) in winter. It is concluded that a seasonal cycle of feed intake, body growth, fibre follicle activity, wool growth and FD occur in fat-tailed Sanjabi sheep.

Production characteristics of white-faced rams have been systematically evaluated over a 140-d test in Wyoming since 1961. Individual test records ( = 4,240) from rams on test were analyzed to determine change over the past 52 yr. Although rams on test are not older, weight on and off test has increased ( < 0.001) since 1961. Weight off test increased 22.7 kg and contributed to an increase ( < 0.001) in clean fleece weight. Rate of gain ( < 0.001) almost doubled over this 50-yr period. Growth efficiency improved from 0.23 ± 0.01 kg/d from 1961 to 1966 to 0.39 ± 0.01 kg/d from 2008 to 2013. Cubic, rather than linear, effects better explain the change in growth characteristics, suggesting a plateau or tapering of these traits. Wool characteristics remain an important component of the test index, and despite increases in body size and gain, wool diameter was unchanged ( > 0.15). Average daily gain correlated ( > 0.67; < 0.001) with lamb and feeder lamb price, with the strongest correlation at a 2-yr ( > 0.76) time lag. U.S. sheep inventory was negatively correlated ( > -0.72; < 0.001) with sheep price and ADG, with the greatest correlation at no time lag. Wool price 0, 2, or 5 yr prior did not correlate ( < 0.1; ≥ 0.5) with spinning count. Influences on white-faced ram selection appear to have largely impacted growth traits while avoiding negative impacts on wool quality.

Background: Sheep are valuable resources for the animal fibre industry. Therefore, identifying genes which regulate wool growth would offer strategies for improving the quality of fine wool. In this study, we employed Agilent sheep gene expression microarray and proteomic technology to compare the gene expression patterns of the body side (hair-rich) and groin (hairless) skins of Aohan fine wool sheep (a Chinese indigenous breed)., Results: Comparing the body side to the groin skins (S/G) of Aohan fine wool sheep, the microarray study revealed that 1494 probes were differentially expressed, including 602 more highly expressed and 892 less highly expressed probes. The microarray results were verified by means of quantitative PCR. Cluster analysis could distinguish the body side skin and the groin skin. Based on the Database for Annotation, Visualization and Integrated Discovery (DAVID), 38 of the differentially expressed genes were classified into four categories, namely regulation of receptor binding, multicellular organismal process, protein binding and macromolecular complex. Proteomic study revealed that 187 protein spots showed significant (p < 0.05) differences in their respective expression levels. Among them, 46 protein entries were further identified by MALDI-TOF/MS analyses., Conclusions: Microarray analysis revealed thousands of differentially expressed genes, many of which were possibly associated with wool growth. Several potential gene families might participate in hair growth regulation. Proteomic analysis also indentified hundreds of differentially expressed proteins.

Sulphur-containing amino acids (SAA) are essential and usually the first limiting amino acids for growth, milk and wool production. The keratin fibre that grows from epidermal tissue is rich in SAA. The rate of fibre growth and its S content are influenced by the availability of SAA. Betaine is a dietary source for a labile methyl group and actively participates in methionine metabolism by donating methyl groups for the remethylation of homocysteine to methionine. Ruminants are capable of synthesizing SAA from inorganic S sources, and most bacteria in the rumen can use inorganic S to meet their requirements for growth. The objective of this study was to examine whether betaine and an inorganic sulphur supplement could provide methyl groups and sulphur amino acids in a way that growth performance and wool production of ewes and lambs are improved. Treatments performed included betaine supplementation, sulphate supplementation and betaine plus sulphate supplementation with five replications for each treatment. The dry matter intake of the ewes was affected by betaine plus sulphate supplementation (p < 0.05). In the ewes, betaine plus sulphate supplementation increased (p < 0.05) the wool growth rate, wool yield, staple length and wool sulphur concentration, while decreasing wool wax and wool yellowness (p < 0.05). In the lambs, wool growth rate, wool yield, fibre diameter, staple length, staple strength, wool sulphur concentration, wool wax and fibre percentage did not differ (p > 0.05) between treatments. In the ewes, plasma methionine concentration increased (p < 0.05) with betaine plus sulphate treatment. No corresponding difference (p > 0.05) was observed in plasma methionine concentration in the lambs. It can be concluded that betaine plus sulphate supplementation has the potential to change wool characteristics in the ewes, while these compounds were without any effect on growth and wool production of the lambs. Combining the two supplements was advantageous., (Journal of Animal Physiology and Animal Nutrition © 2014 Blackwell Verlag GmbH.)

Genome-wide association studies (GWAS) provide a powerful approach for identifying quantitative trait loci without prior knowledge of location or function. To identify loci associated with wool production traits, we performed a genome-wide association study on a total of 765 Chinese Merino sheep (JunKen type) genotyped with 50 K single nucleotide polymorphisms (SNPs). In the present study, five wool production traits were examined: fiber diameter, fiber diameter coefficient of variation, fineness dispersion, staple length and crimp. We detected 28 genome-wide significant SNPs for fiber diameter, fiber diameter coefficient of variation, fineness dispersion, and crimp trait in the Chinese Merino sheep. About 43% of the significant SNP markers were located within known or predicted genes, including YWHAZ, KRTCAP3, TSPEAR, PIK3R4, KIF16B, PTPN3, GPRC5A, DDX47, TCF9, TPTE2, EPHA5 and NBEA genes. Our results not only confirm the results of previous reports, but also provide a suite of novel SNP markers and candidate genes associated with wool traits. Our findings will be useful for exploring the genetic control of wool traits in sheep.

Sheep are valuable resources for the wool industry. Wool growth of Aohan fine wool sheep has cycled during different seasons in 1 year. Therefore, identifying genes that control wool growth cycling might lead to ways for improving the quality and yield of fine wool. In this study, we employed Agilent sheep gene expression microarray and proteomic technology to compare the gene expression patterns of the body side skins at August and December time points in Aohan fine wool sheep (a Chinese indigenous breed). Microarray study revealed that 2,223 transcripts were differentially expressed, including 1,162 up-regulated and 1,061 down-regulated transcripts, comparing body side skin at the August time point to the December one (A/D) in Aohan fine wool sheep. Then seven differentially expressed genes were selected to validated the reliability of the gene chip data. The majority of the genes possibly related to follicle development and wool growth could be assigned into the categories including regulation of receptor binding, extracellular region, protein binding and extracellular space. Proteomic study revealed that 84 protein spots showed significant differences in expression levels. Of the 84, 63 protein spots were upregulated and 21 were downregulated in A/D. Finally, 55 protein points were determined through MALDI-TOF/MS analyses. Furthermore, the regulation mechanism of hair follicle might resemble that of fetation.

The objective of this study was to determine the live weight, body condition scores (BCS) and fleece weight of sheep in four smallholder farming communities of Eastern Cape Province, South Africa. Among the four communities studied, two (Roxeni and Tyabane) were in sweetveld and other two (Luzi I and Luzi II) were in a sourveld. Roxeni and Luzi communities were also engaged in the ram exchange project with the National Wool Growers Association (NWGA). Sixty crossbred ewes and 20 non-descript ewes aged 2 to 3 years were randomly selected from the four communities studied and were measured during their annual shearing in October. They were assessed for average greasy fleece weight per head, body condition score and live weight after shearing. Roxeni sheep were heavier (39.9 ± 1.10 kg) than Tyabane sheep (29.8 ± 1.10 kg). Sheep from Tyabane had the lightest (P <0.05) fleece weight (1.0 ± 1.10 kg) than Roxeni sheep (3.1 ± 1.10 kg). The 2-year-old ewes had similar (P ≥ 0.05) live weight to that of the 3-year-old ewes. However, the 3-year-old ewes had higher (3.3 ± 0.11) (P < 0.05) body condition scores than the 2-year-old ewes (2.8 ± 0.10). Two-year-old ewes also had lower (1.9 ± 0.11 kg) (P < 0.05) fleece weight than the 3-year-old ewes (2.3 ± 0.10 kg). It was concluded that sheep that were raised in the sweetveld had higher live and fleece weights than the ones that were raised on the sourveld. The communities that were engaged on ram exchange project had sheep with higher live weights, body condition score and fleece weight.

The desmoglein 4 (DSG4) gene is a potential candidate in the search for genes that may affect wool traits, because of its function. This study aimed to screen for polymorphisms in partial exon 16 and 3ꞌUTR of the sheep desmoglein 4 DSG4 gene, and to test its possible association with wool length and crimp associated with fur. Overall, 326 sheep were scanned via single-strand conformational polymorphism assay, through three pairs of primers. The breeds included Tan, Han, and TanxHan from China, Polled Dorset from Australia, and Suffolk from Britain genotypes AA, BB, and AB for primer2 and genotypes DD, EE, and DE for primer3 were detected in native breeds. Six SNPs and 3-bp insertion/deletions were found in exon 16, of which 4 lead to amino acid substitutions. In addition, 1 SNP was found in 3ꞌUTR. The DSG4 genotype was found to be strongly associated with all wool traits that were considered in this study (P < 0.01). Sheep with the genotype MM had a higher least square mean compared to sheep with the genotype WW or WM with respect to birth scapular wool length (P < 0.01), crimp number of birth scapular wool crimp (P < 0.01), crimp number of weaning scapular wool crimp (P < 0.01), and crimp number of weaning rump wool crimp (P < 0.01, P < 0.05). In conclusion, our study is the first to demonstrate that the DSG4 gene may be a candidate, or major gene, which influences important wool traits.

Sheep (Ovis aries) are a major source of meat, milk, and fiber in the form of wool and represent a distinct class of animals that have a specialized digestive organ, the rumen, that carries out the initial digestion of plant material. We have developed and analyzed a high-quality reference sheep genome and transcriptomes from 40 different tissues. We identified highly expressed genes encoding keratin cross-linking proteins associated with rumen evolution. We also identified genes involved in lipid metabolism that had been amplified and/or had altered tissue expression patterns. This may be in response to changes in the barrier lipids of the skin, an interaction between lipid metabolism and wool synthesis, and an increased role of volatile fatty acids in ruminants compared with nonruminant animals., (Copyright © 2014, American Association for the Advancement of Science.)

Microalgae are the original source of docosahexaenoic acid (DHA; 22:6n-3) in the marine food chain, and its inclusion in animal feeds has been considered as a means of increasing the DHA level in foods of animal origin. As such, this study aimed to investigate the effects of supplementing an algal meal, high in DHA derived from Schizochytrium spp. (DHA-G), in the diet of Canadian Arcott lambs, on growth, carcass characteristics, wool production, and fatty acid (FA) profiles of subcutaneous adipose tissues (SAT), perirenal adipose tissues (PAT), and skirt muscle (SM). Forty-four lambs were randomly assigned to dietary treatments. Diets consisted of a pelleted, barley-based finishing diet with DHA-G supplemented at 0, 1, 2, or 3% DM as a replacement for flax oil and barley grain. Feed deliveries and orts were recorded daily. Lambs were weighed weekly and slaughtered once they reached ≥ 45 kg live weight. Carcass characteristics, ruminal pH, and liver weights were determined at slaughter. Wool yield was determined on mid-side patches of 100 cm(2) shorn at d 0 and on the day before slaughter (d 105 or 140). Dye bands were used to determine wool growth, fiber diameter, and staple length. Adipose tissues and SM samples were taken at slaughter and analyzed for FA profiles. Data were analyzed using mixed procedure in SAS with orthogonal contrasts testing for linear, quadratic, or cubic responses to increasing levels of DHA-G. Daily DMI, ADG, and G:F were similar as were wool quality and yield (P > 0.05). Carcass characteristics were generally unaffected (P > 0.05), except for body wall thickness (mm), which showed a quadratic response (P = 0.01) with increasing DHA-G. The concentration of eicosapentaenoic acid (EPA; 20:5n-6; mg/100 g fresh tissue) linearly increased (P < 0.001) with DHA-G in both adipose tissues and responded quadratically in SM (P = 0.05). Similarly, DHA (mg/100 g fresh tissue) increased linearly (P < 0.01) with DHA-G in all tissue types (P < 0.001). Supplementing DHA-G decreased (P < 0.001) the n-6:n-3 ratio in all tissues. No effects (P ≥ 0.05) on PUFA or SFA were observed across the 3 tissues, with no response (P ≥ 0.10) in the SFA:PUFA ratio in either SM or SAT; however, the SFA:PUFA ratio linearly decreased in PAT (P = 0.01) as DHA-G increased. These results indicate that DHA-G can be successfully included in the diets of growing lambs, up to 3% DM, with the potential to improve carcass characteristics and the FA profile of adipose tissue and muscle.

Historically, sheep have been selectively bred for desirable traits including wool characteristics. However, recent moves towards extensive farming and reduced farm labour have seen a renewed interest in Easycare breeds. The aim of this study was to quantify the underlying genetic architecture of wool shedding in an Easycare flock. Wool shedding scores were collected from 565 pedigreed commercial Easycare sheep from 2002 to 2010. The wool scoring system was based on a 10-point (0-9) scale, with score 0 for animals retaining full fleece and 9 for those completely shedding. DNA was sampled from 200 animals of which 48 with extreme phenotypes were genotyped using a 50-k SNP chip. Three genetic analyses were performed: heritability analysis, complex segregation analysis to test for a major gene hypothesis and a genome-wide association study to map regions in the genome affecting the trait. Phenotypes were treated as a continuous or binary variable and categories. High estimates of heritability (0.80 when treated as a continuous, 0.65-0.75 as binary and 0.75 as categories) for shedding were obtained from linear mixed model analyses. Complex segregation analysis gave similar estimates (0.80 ± 0.06) to those above with additional evidence for a major gene with dominance effects. Mixed model association analyses identified four significant (P < 0.05) SNPs. Further analyses of these four SNPs in all 200 animals revealed that one of the SNPs displayed dominance effects similar to those obtained from the complex segregation analyses. In summary, we found strong genetic control for wool shedding, demonstrated the possibility of a single putative dominant gene controlling this trait and identified four SNPs that may be in partial linkage disequilibrium with gene(s) controlling shedding., (© 2013 University of Edinburgh, Animal Genetics © 2013 Stichting International Foundation for Animal Genetics.)

Capra hircus, an economically important livestock, plays an indispensable role in the world animal fiber industry. In the present study, using Illumina/Solexa high throughput sequencing technology, we sequenced and de novo assembled the goat skin transcriptome corresponding to the anagen and telogen of the hair growth cycle. Approximately 53Mb of transcriptome sequences consisting of 57,040 high quality contigs was obtained. More than 8300 contigs were predicted to contain a full length coding sequence. Approximately 43% of the total contigs were identified as harboring homologs of sequences from other organisms in the public database. Based on the assembled transcript-derived contigs, we identified about 7000 transcripts that were differentially expressed between the anagen and telogen libraries. These differentially expressed genes were mainly enriched in signal transduction mechanisms, extracellular structures and cytoskeleton from the KOG database and in ECM receptor interaction, focal adhesion and gap junction from the KEGG pathway database, indicating the essential roles of these genes may play in cell-to-cell and cell-to-matrix communications during the active hair growth phase. In addition, many signaling pathway associated ligands and/or receptors were also identified as up-regulated genes during the anagen phase compared with the telogen stage, suggesting that enhanced cross-talk among signaling transduction pathways may be required for anagen of the hair cycle. These differentially expressed genes, especially those that were over-represented in each of the functional clusters and biochemical pathways, provide valuable resources and opportunities for characterizing the gene functions associated with hair fiber growth as well as for breeding elite Cashmere goat species., (Copyright © 2013 Elsevier B.V. All rights reserved.)

The increasing availability of crude glycerin from the biodiesel industry has led to an interest in its use as an energy source in ruminant diets. However, its effects on ruminal fermentation patterns and methane (CH4) production are unclear, and there are no reports on the effect of its inclusion in the diet on wool production or growth of Merino sheep. Thus, the objectives of this study were to determine the effects of increasing levels of crude glycerin on in vitro ruminal fermentation and CH4 production and DMI, BW, feeding behavior, and wool growth and quality in Merino ewes. Crude glycerin (99.2% pure, colorless, odorless, viscous liquid) replaced whole wheat grain in completely pelleted diets at levels of 0%, 6%, and 12% DM in both in vitro and in vivo studies. For in vitro studies, diets were dried and ground through a 1-mm screen and incubated on 2 different days for 24 h. Modified McDougal's buffer and rumen liquor were mixed 3:1, and gas production and CH4 concentration was measured after 6, 12, and 24 h of incubation with pH and IVDMD measured at 24 h. Cumulative gas (mL/g DM) and methane (mL) production was similar (P ≥ 0.35) among dietary treatments. In vitro dry matter disappearance (%) increased (P < 0.01) with increasing concentrations of crude glycerin. For the in vivo study, 39 Merino ewes were randomly assigned to 3 treatments (n = 13 ewes/treatment). Pelleted diets were available continuously for a 10-wk period through the use of automatic feeders. Ewes were weighed every 7 d. Wool yield was determined on mid-side patches of 100 cm(2) shorn at d 0 and d 70. Dye bands were used to determine wool growth and fiber length. Intake and ADG were similar among treatments (P = 0.59). Neither wool yield, length, spinning fineness, nor fiber diameter (μm) were affected after supplementation with crude glycerin (P ≥ 0.13). This study indicates the potential for crude glycerin to be included in the diets of Merino sheep at up to 12% DM without negatively affecting wool yield and quality.

A total of 344 pure animals, representing seven American and South European breeds (White Chiapas Blanca, Brown Chiapas Café, Black Chiapas Negra, Churra Badana, Churra da Terra Quente, Chilean Latxa, and Spanish Merino), were randomly sampled and wool evaluated for isoalcohol scouring yield, length, and proportion for each type of fiber (long-thick, short-thin, and kemp), average of fiber diameter, and F30 (percentage of fibers with a diameter of >30 μm). The objective of this study was to characterize these breeds according to their wool traits. A low percentage of the phenotypic variability in the analyzed animals was due to differences among breeds, and that the largest part of that variability is due to differences within breeds. The obtained topology in the principal coordinates analysis showed the grouping of the three Chiapas breeds clearly separated, but the similarity with their original breed was only evident for Brown Chiapas Café. The three Chiapas sheep breeds must be regarded as clearly sympatric populations.

This study aimed to quantify production loss due to larval challenge in sheep administered a controlled release albendazole capsule (CRC) and thus determine the suitability of CRC treated sheep as a proxy for worm-free sheep in grazing experiments. The experiment used an incomplete 2 × 3 latin square design with 81 Merino wethers. Sheep were either infected (INF) with mixed oral infection of albendazole-susceptible Haemonchus contortus, Trichostrongylus colubriformis, and Teladorsagia circumcincta (initial bolus then thrice weekly maintenance) or remained uninfected (UINF). Worm control treatments were with a CRC (CRCT), threshold treatment with a short-acting anthelmintic when worm egg count (WEC) exceeded 1500 epg (TT) or untreated (UT). The experiment was conducted in two 63-day periods (separated by a 14 day washout period) with infection treatments swapped between periods. A subset of animals was killed at the end of each period for worm counts and tissue sampling. Faecal worm egg count in UINF-UT reached 10,204 and 6078 epg at day 63 in periods 1 and 2, respectively, and remained 0 throughout in the CRT treatments. There was no difference in live weight gain or wool growth of INF-CRCT sheep (67 and 70 g/d) relative to UINF-CRCT (67 and 76 g/d). Live weight gain was significantly lower in INF-UT (27 g/d) and INF-TT (55 g/d) than UINF-UT (88 g/d) or UINF-TT (81 g/d) treatments. During the first infection period, greasy fleece weight growth was significantly lower in INF-UT (6.33 g/d) and INF-TT (6.37 g/d) than UINF-UT (7.80 g/d) or UINF-TT (7.32 g/d) treatments. The effects of infection on production persisted in INF-UT, but not INF-TT sheep for several weeks after termination of infection. Eosinophil counts were elevated in all infected groups and the antibody response to T. colubriformis was greater in INF-CRCT and INF-TT groups compared to uninfected sheep. Together, these results indicate that larval challenge in sheep with a CRC is mildly immunogenic but is not associated with production loss. The results also showed that the CRC itself reduced live weight gain and that anthelmintic treatment at a WEC threshold of 1500 epg reduces production loss during infections and prevents persistence of adverse effects following infection., (Copyright © 2011 Elsevier B.V. All rights reserved.)

The aim of this study was to analyze the effects of shearing on the individual behaviors and rectal temperature profile during the day at hot environment in Awassi lambs. Twenty Awassi male lambs were randomly allocated into shorn (n = 10) and unshorn (n = 10) groups (28.8 ± 0.7 and 29.9 ± 0.7 kg, respectively) and were kept indoor during the experiment. The physiological and behavioral response variables measured were rectal temperature, standing, lying, feeding, ruminating, drinking, locomotor activity, and elimination. The effect of day, time of day, and all interactions on rectal temperature were found significant (P < 0.001). The effect of shearing on the rectal temperatures of lambs was tend to be significant (P = 0.06). Overall, unshorn lambs showed more frequencies of locomotor activity (P < 0.05) and there was a tendency of less standing behavior (P = 0.08) when compared to the lambs in shorn group. The difference of the other behaviors was not significant (P > 0.05). Within the observation hours, there was a tendency of difference for behavioral frequencies between groups especially early in the day and late at night (P = 0.07). But during the day, the difference of behavior type between groups was highly significant at 1300 and 1600 hours (P < 0.01 and P < 0.001, respectively). The findings of the current study showed that the behavior of shorn lambs changed with the changing of environmental heat and showed more behavioral differences at 1300 hours but they tend to cope with heat stress better than unshorn lambs in a hot environment when their rectal temperatures were compared.

This investigation was conducted to evaluate the comparative productive performances and effect of some environmental factors on wool characteristics of Arkharmerino × Ghezel (Ar × Gh) and Arkharmerino × Moghani (Ar × Mo) crossbreed sheep. The mid-side fleece samples taken from animals during 2 years (2007-2008) were analyzed. Each sample was measured for average fiber diameter, fiber diameter variability, staple length, proportion of medullated fiber, proportion of kemp, and comfort factor. The comparative values for these fleece characteristics in F(3) generation Ar × Gh were 28.78 ± 0.48 μm, 36.84 ± 1.16%, 11.94 ± 0.35 cm, 7.07 ± 0.93%, 1.02 ± 0.23%, and 68.93%, respectively; while those traits were 29.79 ± 0.43 μm, 41.86 ± 1.16%, 11.96 ± 0.37 cm, 8.13 ± 1.06%, 2.71 ± 0.45%, and 63.33 ± 3.66% for Ar × Mo, respectively. The effects of genotype, sex, birth type, and year of birth were analyzed. Genotype had a significant (P < 0.01) effect on average fiber diameter and proportion of kemp, and Ar × Gh crossbreeds had lower diameter with less proportion of kemp. The two differences in fiber characteristics that were attributable to sex were fiber diameter variability and proportion of medullated fiber, and females had higher measure than males for both traits. Statistical analysis showed that crossbreeding with Arkharmerino generally had positive effects on the fleece favored to be used in the hand woven authentic carpet production.

The Local Awassi, a triple-purpose breed for meat, milk, and carpet-wool production, is a low-prolific, hardy breed that is well adapted to the unfavorable conditions of the Middle East, where it is managed under traditionally extensive to semi-extensive conditions. Breeding work with the Awassi has included within-breed selection, crossbreeding, and gene introgression. Those efforts resulted in a variety of Awassi-derived genotypes that successfully occupy semi-intensive as well as intensive production systems. Thus, within-breed selection resulted in development of the "Improved Awassi"-a dairy-type Awassi strain which, under intensive management, produces over 500 l milk/ewe annually; crossbreeding with the East Friesian breed led to the development of the Assaf dairy breed, which exceeds the Improved Awassi in prolificacy and in year-round breeding activity, and introgression of the B allele of the FecB locus into the Awassi and Assaf breeds resulted in the formation of the prolific Afec Awassi and Afec Assaf strains, with prolificacies of 1.9 and 2.5 lambs born per ewe lambing, respectively. Advanced molecular genetics tools have enabled a better understanding of how the Awassi breed was formed during domestication and have uncovered differences in its genetic structure compared to other breeds. Implementing large-scale selection schemes that implement emerging new information on the sheep genome, overcoming threats of inbreeding depression, and further breeding for high uterine capacity are the new breeding goals for the Awassi, Assaf, and their derivatives.

The alpaca is the most important fiber producer of the South American camelid species, and is an important source of income for the Andean communities. Nowadays, fiber diameter is considered the main selection objective in alpaca populations throughout the world. However, fiber diameter increases with the age of the animals, and it would be preferable to select those animals that maintain a thin fiber throughout their life span. The goal of this study was to describe the genetic relationship between fiber diameter at weaning age (6 mo) and the evolution of fiber diameter along the life span. The analysis of the evolution of fiber diameter was studied as a useful model for canalization and as a longitudinal trait by hierarchical Bayesian analysis. The results suggested that substantial genetic variation exists for fiber diameter and also for the variability and linear growth of the fiber diameter. Thus, a genetic selection program is plausible to modify the evolution of fiber diameter with time, together with a favorable correlated decrease in fiber diameter., (© 2011 American Society of Animal Science. All rights reserved.)

Keratin IF (KRT) and keratin-associated protein genes encode the majority of wool and hair proteins. We have identified cDNA sequences representing nine novel sheep KRT genes, increasing the known active genes from eight to 17, a number comparable to that in the human. However, the absence of KRT37 in the type I family and the discovery of type II KRT87 in sheep exemplify species-specific compositional differences in hair KRT genes. Phylogenetic analysis of hair KRT genes within type I and type II families in the sheep, cattle and human genomes revealed a high degree of consistency in their sequence conservation and grouping. However, there were differences in the fibre compartmentalisation and keratinisation zones for the expression of six ovine KRT genes compared with their human orthologs. Transcripts of three genes (KRT40, KRT82 and KRT84) were only present in the fibre cuticle. KRT32, KRT35 and KRT85 were expressed in both the cuticle and the fibre cortex. The remaining 11 genes (KRT31, KRT33A, KRT33B, KRT34, KRT36, KRT38-39, KRT81, KRT83 and KRT86-87) were expressed only in the cortex. Species-specific differences in the expressed keratin gene sets, their relative expression levels and compartmentalisation are discussed in the context of their underlying roles in wool and hair developmental programmes and the distinctive characteristics of the fibres produced., (© 2011 John Wiley & Sons A/S.)

Grazing ability is difficult to record in animals under free-ranging conditions without sophisticated methods. Alternatively, grazing ability may be indirectly inferred from changes in BW and production characteristics during the grazing period. The present study investigated the effect of grazing on resource-limited rangelands on BW, wool characteristics, and offspring weaning weights in nine hundred five 5/8, 7/8, and fullblood Merino ewes of 2 to 7 yr of age during a grazing period of approximately 2.5 mo (between January and March). A total of 469 ewes gave birth to a single lamb, 248 to twin lambs, and 188 did not give birth. Body weights were measured and wool samples taken before and after the ewes were allowed to graze freely on the rangelands; absolute change in BW and change in BW as a percentage of initial BW were estimated. On average, grazing on resource-poor rangelands resulted in BW loss, a reduction in fiber diameter and its CV, and increased staple length. Animals with finer wool at the start of the grazing period lost phenotypically (r = -0.07, P < 0.05) and genetically (r = -0.23, P < 0.05) less BW during the grazing period and had a greater probability to carry 1 lamb (or 2) to term (P < 0.05). Animals that lost less BW produced more greasy fleece (r = 0.09, P < 0.01). Body weight change did not significantly influence offspring weaning weights. Change in BW was moderately heritable at h(2) = 0.29; fiber diameter was strongly heritable at h(2) = 0.51. Animals with the least inclusion of Merino genetics lost more BW (P < 0.01) during the grazing period and had a more uniform fiber diameter (P < 0.05) but shorter staples (P < 0.05) and less fleece (P < 0.0001) than animals with a greater level of Merino genetics. Our results indicate that animals with finer wool appeared to be better adapted to the cold Nevada desert. Thus, selection for finer wool may positively influence adaptability to resource-limited cold climate conditions; alternatively, BW change may be selected for directly. Because nutritional deficiencies during pregnancy can have adverse consequences for the offspring, indirect selection for grazing ability would foremost result in healthier ewes that can produce lambs and wool without compromising their welfare.

Objective: To assess in weaned lambs the palliative effects of the non-steroidal anti-inflammatory drug, carprofen, following intradermal injection of cetrimide to induce non-surgical mulesing., Procedures: We allocated 40 weaned lambs (20-22 weeks old) to four groups of 10 animals: (1) control, 2) conventional surgical mules, (3) intradermal treatment and (4) intradermal treatment + carprofen. Non-surgical mulesing was induced by intradermal injection of 4% (w/w) cetrimide + 3% (w/w) polyvinylpyrrolidone in water. In group 4, carprofen (4 mg/kg, SC) was administered 1 h before intradermal treatment. Five weaners, including an animal from each treatment, were run in each pen. Neutrophil to lymphocyte ratio, cortisol, beta-endorphin and haptoglobin levels and rectal temperature were monitored at least daily for the first 7 days after treatment, then weekly until day 28. Body weight was measured weekly and behaviour was measured every 15 min for 12 h on the day of treatment, then on days 1, 2, 4, 6, 12, 21 and 28 following treatment., Results: The intradermal treatment resulted in high fever and elevated blood cortisol by 12 h. Rectal temperatures were significantly elevated until 5 days after treatment, cortisol was elevated until 3 days after treatment, haptoglobin for at least 7 days after treatment and the neutrophil to lymphocyte ratio until 4 days after treatment. Average daily gain was depressed in the week following treatment. Abnormal behaviours (hunched standing, stiff walking, pawing, lateral lying and lying intention) were increased on the day of treatment and for 6 days post treatment. Carprofen reduced the time spent in abnormal behaviours by approximately two-thirds but did not ameliorate the physiological responses to the intradermal treatment., Conclusions: In weaner sheep, carprofen ameliorated the behavioural responses, but was unable to provide relief from the intense and sustained physiological responses to non-surgical mulesing by intradermal injection of cetrimide. Systemic side-effects may be unavoidable with formulations based on quaternary ammonium compounds that are designed to reduce the risk of fly strike in sheep by remodelling breech tissue through induction of tissue necrosis.