Wool Growth Research Articles

Influence of feed additive Enervit on the wool productivity of young rams of Dagestan mountain breed

Sheep breeding has great national and economic importance for the Republic of Dagestan. The creation of optimal feeding conditions for sheep signifi cantly accelerates the process of improving their productive characteristics and the quality of the products obtained. The feed factor promotes the growth of wool and improves its quality in fi ne-wooled sheep breeds. The study of the influence of biologically active substances on economically useful traits of sheep is an urgent task. The purpose of the research was to study the infl uence of the new probiotic feed additive Enervit in the rations of young sheep of Dagestan mountain breed on wool productivity and its quality. As a biologically active additive in the ration of young sheep of Dagestan mountain breed a probiotic feed additive Enervit was used consisting of a compound of mineral additives such as chalk, table salt, feed diammonium phosphate, calcium sulfate, copper sulfate, zinc sulfate, manganese sulfate and cobalt chloride. The experiment was carried out by the method of groups on young rams with an average live weight of 26,2 kg. The sheep of the control group received a ration without the introduction of the feed additive Enervit, and to the animals of the 1st experimental group were added the drug in the amount of 10, 15, 20 g/head/day, depending on the age of 4, 8 and 12 months. The young rams of the 2nd experimental group were given Enervit, respectively, for these age periods 13, 24 and 26 g. Based on the indicators of the amino acid composition of the wool of sheep of the experimental groups, its best quality was characteristic of animals that received the feed additive Enervit in the amount of 10, 15 and 20 g/head/day at the age of 4, 8 and 12 months, respectively. The addition of the drug to the rations of Dagestan mountain sheep in such the amount leads to an improvement in the metabolism in the body of animals, as a result of which the quality indicators of the wool of the sheep of the 1st experimental group increased.

Identification of the KAP27-1 gene in sheep and its effect on wool traits

ABSTRACT The keratin-associated proteins (KAPs) are structural components of wool and hair fibres, with over 90 genes that encode these proteins having been identified in mammalian species. A KAP gene called KRTAP27-1 was recently identified in goats, but the gene has not been reported in the closely related ruminant species sheep. In this study, we used a polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis to find ovine KRTAP27-1 and investigate nucleotide sequence variation in the gene. Our analysis revealed four sequence variants (named A to D) in 399 New Zealand Merino × Southdown-cross sheep. Within these sequence variants there were five single nucleotide polymorphisms (SNPs) in the coding region, including two non-synonymous SNPs. Six genotypes (AA, AB, AC, BB, BC and BD) of KRTAP27-1 were detected, and for the three genotypes with a frequency of over 5.0%, sheep of genotypes AB and BB produced wool of higher mean staple length (MSL) and higher greasy fleece weight (GFW) than sheep of genotype AA. These results suggest that variation in ovine KRTAP27-1 may be affecting wool growth and thus production.

Research results on the use of frozen yak sperm

Mongolians have specific, historical traditions of nomadic ways for pastoral animal breeding. Since ancient times they are bred the five kinds of livestock with unique capabilities, adapted to four seasons grazing under harsh natural and climatic conditions of Central Asian mountainous and used their benefits. Unique biological quality of Mongolian livestock that helps the animal withstand the cold and feed shortage seasons in despite of feeding pasture plants only for all year round is an evidence of its pasture usability. Better growth of hair and wool of hardy Mongolian livestock, which are able to grow under severe natural and climatic conditions, during summer and autumn, and fibers appeared around the hair base during cold season make the animals resistant to cold. Mongolian livestock are the animals, which withstand very well the fluctuations of both heat and cold, have better maintenance of body heat and ecological adaptation, stronger body conformation, resist various diseases, and have alive behavior, better sociability and genetic capacity. Livestock in Mongolia are considered to be part of the nation’s wealth and are subject to state protection under the country’s constitution. Agriculture, particularly animal husbandry is one of the basic economic sectors of Mongolia and the sector comprises 84.2% of the country’s Gross Agricultural Product and is the only source of income for 18.5% of total households (Mongolian Statistical Yearbook, 2016). In addition, livestock and livestock-derived processed exports account for about 8.7% of foreign exchange earnings. In 2020, Mongolia has recorded the highest number of livestock at 67.1 million, of which 4.1 million are horses, 4.7 million are cattle, 0.47 million are camels, 30.0 million are sheep and 27.7 million are goats. The action plan of the Mongolian government, set a goal “In addition to increasing the number of high-yielding livestock, implementing a policy to support rural development by creating an appropriate herd structure, improving productivity and quality, and developing intensive animal husbandry, and raising highly productive livestock and milk, to protect the gene found of good beef cattle and to expand the breeding and selection of nuclear herds”. Therefore, important to protect the high-productive yak's gene found are to take semen from yak bull. The yak is bred in Mongolia, Tibet, Nepal, Kyrgyzstan, the Gorno-Altai region of the Russian Federation, the Himalayas, the Altai, and the Pamirs, and in the surrounding mountainous areas at an altitude of about 2,000 meters above sea level.

Rotational grazing and multispecies herbal leys increase productivity in temperate pastoral systems – A meta-analysis

Reducing greenhouse gas emissions associated with ruminant livestock production is important for climate change mitigation. Regenerative Agriculture (RA) practices are increasingly promoted to improve forage production and livestock performance in temperate livestock systems. These practices include i) rotational grazing (RG) of livestock around multiple subunits of pasture to achieve ungrazed periods of ‘rest’, and ii) herbal leys (HL), where perennial forbs such as chicory, lucerne and trefoils are included as components in multi-species swards. While there are plausible mechanisms for adoption of these practices to improve agricultural productivity, quantitative syntheses of their impacts are required. Here, we conduct a systematic review and meta-analysis of the effects of RG and HL practices on herbage dry matter (DM) production, animal daily liveweight gain (DLWG), and sheep wool growth in temperate oceanic regions. We use quantitative predictors in our Bayesian hierarchical models to investigate the role of rest period and stocking density in RG systems, and specific plant traits and sward diversity in HL. We found that herbage DM increased by 0.31 t.ha−1 over a growing season as the proportion of rest in an RG grazing system increased from 0 to 1. Stocking density significantly moderated the effect of rest period on sheep and cattle DLWG; at higher stocking densities, longer rest periods were required to maintain livestock growth rates. In HL studies, herbage DM yielded 1.63 t.ha−1 more per metre of increased sward root depth and a sward entirely comprised of legumes yielded 2.20 t.ha−1 more than when no legumes were present. Sheep DLWG increased by 3.50 g.day−1 per unit increase in leaf nitrogen concentration (mg.g−1), but we could not determine an effect of leaf condensed tannin content on animal performance. Although there remain differences between the RG and HL study treatments meta-analysed here and RA in practice, our results provide empirical support for some of the mechanisms attributed to increased pasture and livestock productivity following adoption of selected RA grazing practices.

Managing Internal Parasites of Small Ruminants using Medicinal Plants a Review on Alternative Remedies, Efficacy Evaluation Techniques and Conservational Strategies

Throughout the world, internal parasites are a majorhindrance to small ruminant production. The most common internal parasites ingrazing small ruminants are likely to be gastrointestinal nematodes. They causea reduction in live-weight gain, wool growth, poor reproductive performance,and increased production costs and thus hamper global food security.Pharmaceutical control continues to be the main measure used to manage orcontrol internal parasites, however as the resistance of internal parasite populationsspreads, the efficiency of this method in resource-limited environments becomeslimited and complex. Efforts to curb production losses caused by internalparasites have led communal farmers to use other treatments such as locallyavailable indigenous medicinal plants to control internal parasites as analternative to pharmaceuticals. However, many medicinal plants still need to beevaluated for their efficacy and efficiency using both in vitro as wellas in vivo methods. Furthermore, in many developing countries, the useof these plants is not well documented nor they are guided by certain rules andregulations to conserve them. Therefore, the objective of this review was todocument various remedies prepared from medicinal plants to manage internalparasites in small ruminants. A further objective was to evaluate techniquesused to determine the safety and efficacy of these plants and to suggestpossible strategies to conserve such useful plants and the knowledge associatedwith them.

Integration Analysis of Transcriptome and Proteome Reveal the Mechanisms of Goat Wool Bending.

Zhongwei goat is a unique Chinese native goat breed for excellent lamb fur. The pattern of flower spikes of the lamb fur was significantly reduced due to the reduction of the bending of the hair strands with growth. In order to explore the molecular mechanism underlying hair bending with growth, we performed the comprehensive analysis of transcriptome and proteome of skins from 45-days, 108-days and 365-days goat based on TMT-based quantitative proteomics and RNA-seq methods. In the three comparison groups, 356, 592 and 282 differentially expressed proteins (DEPs) were screened, respectively. KEGG pathway analysis indicated that DEPs were significantly enriched in a set of signaling pathways related to wool growth and bending, such as ECM-receptor interaction, PI3K-Akt signaling pathway, PPAR signaling pathway, protein digestion and absorption, and metabolic pathways. In addition, 20 DEPs abundance of goat skin at three development stages were examined by PRM method, which validated the reliability of proteomic data. Among them, KRT and collagen alpha family may play an important role in the development of goat hair follicle and wool bending. COL6A1, COL6A2, CRNN, TNC and LOC102178129 were identified as candidate genes based on combined analysis of transcriptome and proteome data and PRM quantification. Our results identify the differential expressed proteins as well as pathways related to the wool bending of Zhongwei goats and provide a theoretical basis for further revealing the molecular mechanism underlying wool bending of goats.

High performance of growing lambs grazing Paspalum notatum INIA Sepé with energy-protein supplement including sorghum-DDGS

Sorghum dried distillers’ grain with soluble (S-DDGS) has not been utilized as supplement in lamb growing and finishing diets under grazing conditions in summer. The hypothesis was that the performance of post-weaning lambs grazing Paspalum notatum (PN) INIA Sepé supplemented with an energy-protein diet (whole sorghum grain [SG], and soybean meal [SM]) is not reduced by the inclusion of 40% S-DDGS. During 82 days, in summer, 42 Merino Dohne male lambs (130 ± 7.6 days of age, 32 ± 2.4 kg of body weight [BW], and 2.2 ± 0.2 body condition score [BCS]) were evaluated, in a completely random experimental design with three treatments and two replicates each (n = 14 each one). All lambs grazed PN INIA Sepé and in two treatments they were daily supplemented (1.7% BW) with different components. The treatments were: PN (control group, no supplementation), SGSM (70% SG, 30% SM) and DDGS (45% SG, 40% S-DDGS, and 15% SM). Supplemented lambs had higher (P<0.0001) body weight gain (BWG), final BW and wool growth (140 and 126 g/a/d, 43.5 and 42.4 kg; 1814 and 1892 µg/cm2/d for DDGS and SGSM, respectively) than control lambs (40 g/a/d; 35.5 kg; 1353 µg/cm2/d) (P<0.0001), without differences between supplemented groups. Gastrointestinal nematodes infestation (GIN) was affected by the treatments on day 69, where supplemented animals showed lower infestation levels than control lambs (P=0.0024). The inclusion of S-DDGS in the supplement did not reduce the productive performance of the lambs when the concentration of crude protein and energy remained constant.

Association of SNPs within PTPN3 gene with wool production and growth traits in a dual-purpose sheep population

Protein tyrosine phosphatase non-receptor type 3 (PTPN3), a member of the membrane-associated non-receptor protein tyrosine phosphatase (PTP) family, plays significant roles in the cytoplasm and affects the development and growth of skin and hair. A recent study identified the PTPN3 as the potential gene related to sheep wool quality. To detect single-nucleotide polymorphisms (SNPs) of PTPN3 and elucidate its association with wool production and growth traits in fine wool sheep a total of 644 healthy SG (South African mutton merino♂ × Gansu alpine fine-wool sheep♀, SG) and SSG (South African mutton merino♂ × SG♀, SSG) hybrid sheep were selected. Pooled-DNA sequencing and SNPscan methods were used to scan and genotype SNPs within PTPN3. Association analyses between SNPs and wool production and growth traits were implemented. Consequently, the results revealed that PTPN3 has six SNPs (two missense mutations, one synonymous mutation, and three intron mutations), of which four loci (SNP2, SNP3, SNP4, and SNP5) were significantly positively correlated with growth and wool traits (p < 0.05). SNP4 was significantly (p < 0.05) linked with thigh wool length, and SNP6 was significantly (p < 0.05) associated with abdomen wool length. Moreover, one strongly linked SNP block was identified to be correlated with wool production and growth traits (body weight and body size). The significant SNPs founded by this study could serve as useful genetic markers for breeding fine-wool sheep.®

Biological capacity of Mongolian native cattle

Unique biological quality of Mongolian livestock that helps the animal withstand the cold and feed shortage seasons in despite of feeding pasture plants only for all year round is an evidence of its pasture usability. Better growth of hair and wool of hardy Mongolian livestock, which are able to grow under severe natural and climatic conditions, during summer and autumn, and fibers appeared around the hair base during cold season make the animals resistant to cold. Mongolia has a long tradition of raising livestock in the vast territory. This is based on a system of pastoral herding consisting of five kinds of livestock. Mongolians have specific, historical traditions of nomadic ways for pastoral animal breeding. Since ancient times they are bred the five kinds of livestock with unique capabilities, adapted to four seasons grazing under harsh natural and climatic conditions of Central Asian mountainous and used their benefits. Although Mongolian livestock breeds are well adapted to harsh weather conditions, their productivity is not especially high. Animal husbandry is the fundamental source of food consumption and raw materials for the national economy, contributing 20% of the total GDP. Livestock workers make up 34.5% of the total labor force. The livestock sector is responsible for 90% of total agricultural production and comprises 12.5% of all exports. Currently, Mongolia has: 2 breeds and 2 strains of horses, 4 breeds of camel, 3 breeds and 1 breeding group of cattle, 13 breeds, 3 breed groups and 3 breeding races and 3 strains of sheep and 7 breeds, 4 strains of goats forming genetic resources of Mongolian livestock. The main products of the livestock sector are meat, milk, wool, cashmere and hides. Due to the harsh climatic conditions of Mongolian livestock, their wools grow well in the summer and autumn, and during the cold season, cashmere is covered with cashmere and they are resistant to cold. Mongolians have specific historical traditions of managing nomadic husbandry of five types of livestock populations, which are adapted to all year round grazing under severe natural and climatic conditions of Central Asian plateau, growing and breeding of wealth producing livestock populations and utilizing their animal products since ancient times.

Integrated Analysis of lncRNA and mRNA Reveals Novel Insights into Wool Bending in Zhongwei Goat.

Simple SummaryThe high-quality lambskin of the Chinese Zhongwei goat has a high economic value. The quality of lamb skin is mainly affected by the curvature of the wool, which is regulated by the growth and development of hair follicles. In this study, the expression profiles of long non-coding RNAs (lncRNAs) of 45-day-old and 108-day-old Zhongwei goats were constructed by the Ribo Zero RNA sequencing. A total of 60 differential lncRNAs and 352 differential mRNAs were identified. The functional annotation of differential lncRNAs target genes showed that they were mainly enriched in PI3K-Akt and Arachidonic acid metabolic signaling pathways. In combination with qRT-PCR and WGCNA results, we speculate that LOC102172600 and LOC102191729 might affect hair follicle development and wool curvature by regulating the target genes. These results provide new insights into the potential role of lncRNA in regulating wool bending.Chinese Zhongwei goat is a rare and precious fur breed as its lamb fur is a well-known fur product. Wool bending of lamb fur of the Zhongwei goat is its most striking feature. However, the curvature of the wool decreases gradually with growth, which significantly affects its quality and economic value. The mechanism regulating the phenotypic changes of hair bending is still unclear. In the present study, the skin tissues of Zhongwei goats at 45 days (curving wool) and 108 days (slight-curving wool) after birth were taken as the research objects, and the expression profiling of long non-coding RNAs (lncRNAs) and mRNAs were analyzed based on the Ribo Zero RNA sequencing (RNA-seq) method. In total, 46,013 mRNAs and 13,549 lncRNAs were identified, of which 352 were differentially expressed mRNAs and 60 were. lncRNAs. Functional enrichment analysis of the target genes of lncRNAs were mainly enriched in PI3K-Akt, Arachidonic acid metabolic, cAMP, Wnt, and other signaling pathways. The qRT-PCR results of eight selected lncRNAs and target genes were consistent with the sequencing result, which indicated our data were reliable. Through the analysis of the weighted gene co-expression network, 13 co-expression modules were identified. The turquoise module contained a large number of differential expressed lncRNAs, which were mainly enriched in the PI3K-Akt signaling pathway and cAMP signaling pathway. The predicted LOC102172600 and LOC102191729 might affect the development of hair follicles and the curvature of wool by regulating the target genes. Our study provides novel insights into the potential roles of lncRNAs in the regulation of wool bending. In addition, the study offers a theoretical basis for further study of goat wool growth, so as to be a guidance and reference for breeding and improvement in the future.

Sulfur-containing compounds of wool and their role in the processes of wool growth and the formation of physicochemical properties of fibers

Sulfur-containing compounds of wool and their role in the processes of wool growth and the formation of physicochemical properties of fibers

Role of Sulfur Metabolism Gene and High-Sulfur Gene Expression in Wool Growth Regulation in the Cashmere Goat.

Sulfur, an essential mineral element for animals, mainly exists in the form of organic sulfur-containing amino acids (SAAs), such as cystine, methionine, and cysteine, within the body. The content, form, and structure of sulfur play an important role in determining the wool fiber quality. In addition, keratin-associated proteins, one of the most crucial wool fiber components, are rich in SAAs. However, sulfur metabolism from the blood to the skin and hair follicles remains unclear. In this study, we analyzed high-sulfur protein gene and sulfur metabolism genes in the cashmere goat and explored the effects of melatonin on their expression. In total, 53 high-sulfur protein genes and 321 sulfur metabolism genes were identified. We found that high-sulfur protein genes were distributed in the 3–4 and 144M regions of chromosome 1 and the 40–41M region of chromosome 19 in goats. Moreover, all year round, allele-specific expression (ASE) is higher in the 40–41M region of chromosome 19 than in the other regions. Total of 47 high-sulfur protein genes showed interaction with transcription factors and cofactors with ASE. These transcription factors and cofactors were inhibited after melatonin implantation. The network analysis revealed that melatonin may activate the sulfur metabolism process via the regulation of the genes related to cell energy metabolism and cell cycle in the skin, which provided sufficient SAAs for wool and cashmere growth. In conclusion, our findings provide a new insight into wool growth regulation by sulfur metabolism genes and high-sulfur protein genes in cashmere goats.

Wool production in Dohne Merino, Dormer, Merino and South African Mutton Merino lambs

In this study, the wool growth of Dohne Merino, Dormer, Merino and South African Mutton Merino (SAMM) lambs reared on a feedlot diet (10.62 MJ ME/ kg feed, 20.7% crude protein) was monitored from about two months old until the lambs were shorn as yearlings. The 100 cm2 patches on the left sides of the lambs were sheared monthly and the clippings were weighed to determine the wool growth rate. At approximately one year old, the lambs were shorn and the fleeces were weighed. A mid rib fleece sample was also retrieved from each lamb for quality analysis. Merino lambs presented the highest wool growth rates (12.943 g/day) and fleece weights (6.140 kg), whereas Dormer lambs exhibited the lowest values for these traits (8.487 g/day and 3.330 kg, respectively (P &lt;0.05)). The lack of differences between Dohne Merino (9.720 g/day and 4.671 kg) and SAMM (10.553 g/day and 4.158 kg) lambs for these wool growth rate and fleece weight traits was attributed to disparities in live weight (86.8 kg and 105.2 kg, respectively (P &lt;0.05), with heavier SAMM lambs offsetting the expected variations in fleece weight. Wool from Dohne Merino and Merino sheep had the finest fibre diameters (&lt;21 μm), followed by SAMM wool (22–23 μm), with Dormers producing coarse wool (&gt;27 μm). These results could be used as guidelines in sheep production to predict the income contribution of wool from these breeds.

Genetic diversity and population structure of Tibetan sheep breeds determined by whole genome resequencing.

Tibetan sheep is one of primitive Chinese sheep breeds, which achieved the divergence about 2500 years ago in Qinghai plateau region. According to different geographic conditions, especially altitudes, Tibetan sheep evolved into different breeds. In this study, we performed whole genome resequencing of 5 representative Tibetan sheep breeds. Comparative genomic analysis showed that they can be divided into different clades with a close genetic relationship. However, some genes with common selective regions were enriched for hypoxic adaptability in different breeds living at higher altitude, including GHR, BMP15, and CPLANE1. Furthermore, breed-specific selective regions about physical characteristics, especially wool growth, were found in genes such as BSND, USP24, NCAPG, and LCORL. This study could contribute to our understanding about trait formation and offer a reference for breeding of Tibetan sheep.

Protein requirements for maintenance and growth of Corriedale lambs

The protein requirements of lambs for growth and fiber production can be breed specific. The Corriedale is a dual-purpose lamb breed, suitable for fleece and meat production; however, there is no information regarding the specific protein requirements for its growth and maintenance. In this study, we aimed to determine the protein requirements of castrated Corriedale lambs for maintenance, weight gain, and wool growth. Purebred Corriedale lambs with average body weights (BW) of 28, 33, and 38 kg were distributed into three respective trial groups. Their requirements of net protein for maintenance (NPm), metabolizable protein for maintenance (MPm), net protein for weight gain (NPg), net protein for wool growth (NPw), metabolizable protein for weight gain (MPg), metabolizable protein for wool growth (MPw), and their efficiencies for metabolizable protein use were determined. The NPm and MPm of the Corriedale lambs with 28–38 kg BW were 1.44 ± 0.58 g/d/kg0.75 and 3.07 ± 1.28 g/d/kg0.75 of their fasting BW, respectively, and the MP efficiency use for maintenance was 0.47. The NPg and NPw increased with the lambs’ weight gain (from 100 to 250 g/day) and ranged from 9.53 ± 0.001–21.8 ± 0.003 and 7.13 ± 0.038–24.4 ± 0.079 g/d, respectively, in the lambs with 28–38 kg BW. The partial MP efficiencies for the maintenance use of a fleece-free body and wool protein retention were 0.72 and 0.27, respectively. The MPg and MPw ranged from 13.2 ± 0.002–30.3 ± 0.004 g/d and 26.4 ± 0.14–90.4 ± 0.29 g/d, respectively, in the lambs with 28–38 kg BW and an average daily weight gain of 100–250 g. The findings of this study can help feeding systems to improve their protein requirement recommendations for Corriedale sheep in the future.

РЕЗУЛЬТАТЫ ИСПОЛЬЗОВАНИЯ САХАРНОЙ СВЁКЛЫ И ПРОДУКТОВ ЕЁ ПЕРЕРАБОТКИ В КОРМЛЕНИИ ЛАКТИРУЮЩИХ ОВЦЕМАТОК

In the beet-growing regions of our country, when producing sugar beet as a technical crop, it is advisable to use it to replace concentrates in feeding lactating sheep in up to 1.5-2.0 kg per head per day. This helps to increase the nutritional value and sugar level in the eaten feed with a stable receipt of metabolic energy and digestible protein. The replacement of a signifi cant part of the concentrates with sugar beet has a positive eff ect on milk production and wool growth.

Modelling a Transition from Purebred Romney to Fully Shedding Wiltshire-Romney Crossbred.

Simple SummaryA flock of full-fleeced ewes could be bred to shed all their fleece through the repeated crossbreeding of ewes with shedding rams. This shedding flock would then not need to have their low value wool removed, thus reducing the associated expenses. This study used a simulation model to explore changes in the sheep numbers of different crosses, production, cashflow, and profit during the crossbreeding period. It took 12–15 years of crossbreeding to achieve a fully-shedding third or fourth cross flock. Economically, crossbreeding to a shedding flock compared favourably with farming a full-fleeced flock. More data on the performance of shedding sheep in New Zealand would improve the accuracy of model predictions.Considering the current low prices for coarse wool (fibre diameter > 30 µm), a grading up transition to a shedding flock may eliminate wool harvesting costs and increase sheep farm profit. This transition could be achieved by breeding non-shedding ewes with Wiltshire rams. A bio-economic system-dynamics model of a pastoral sheep farming enterprise was used to simulate this grading up transition from 2580 Romney ewes to a similarly-sized flock of fully shedding third or fourth cross Wiltshire–Romney ewes. The total annual sheep feed demand was constrained within a ±5% range to minimise disruption to the on-farm beef cattle enterprise. Wool harvesting expenses were eliminated after seven years of transition, and with reduced feed demand for wool growth, the post-transition shedding flocks had more ewes producing more lambs and achieving greater annual profit compared with the base Romney flock. The net present values of transition were 7% higher than the maintenance of the base Romney flock with a farmgate wool price of $2.15/kg. Results suggest that coarse wool-producing farmers should consider a grading up transition to a shedding flock, and the collection of data on the production of Wiltshire–Romney sheep in New Zealand would improve the accuracy of model predictions.

Environmental influence on Merino sheep wool quality through the lens of seasonal variations in fibre diameter

Wool production in arid and semiarid rangelands is strongly affected by environmental variability. Seasonal fluctuations of the environmental conditions drive variations in the nutritional status of the sheep, wool growth and quality. The variation of fibre diameter during the annual growth period can be observed through the Fibre Diameter Profiles (FDP). The FDP provide a retrospective description of animal responses to varying environmental and management conditions during the wool growth period. Certain characteristics of FDP influence wool quality because this is associated with the performance during processing. The aim of this paper was to assess the variation of the FDP during the 2014–2015 wool growth period on farms located in a longitudinal environmental gradient of Northern Patagonia, Argentina. Some features of the FDPs were found to be associated to the geographical location of the farms. For example, the minimal fibre diameter occurred at different times on the farms during the annual wool growth. The results of this paper support the relevance of the environment in generating seasonal variations in fibre diameter, which might be associated to animal stressful circumstances. However, future research is needed to better understand the influence of climatic conditions and other stressful circumstances for animals.

Chronic elevation of plasma cortisol causes differential expression of predominating glucocorticoid in plasma, saliva, fecal, and wool matrices in sheep

There is increasing interest in using nonblood measures of glucocorticoids to assess the physiological response to chronic stress conditions. In sheep, cortisol has been measured in various matrices including saliva, feces, and wool, but comprehensive studies of the relationship between plasma concentrations of cortisol and concentrations in these nonblood matrices are lacking. Therefore, we tested the hypothesis that administration of cortisol to sheep would result in elevated concentrations of cortisol in blood, saliva, feces, and wool. Merino ewes were administered with saline or 2 mg/kg BW/d hydrocortisone acetate (HCA) by intramuscular (i.m.) injection for 28 d. This treatment was imposed to mimic circulating cortisol concentrations experienced during periods of chronic stress. Cortisol and cortisone were directly measured in plasma, saliva, and wool before, during, and after treatment with saline or HCA. A 14-d pre-treatment and a 14-d post-treatment period were used to measure time taken for glucocorticoid concentrations in each of the matrices to return to baseline levels. Cortisol was also measured in feces before, during, and after treatment. Wool growth was also measured. Before treatment, there was no difference in the concentration of cortisol or cortisone in plasma, saliva, feces, or wool in animals treated with saline or HCA. In contrast, treatment with HCA increased (P < 0.05) concentrations of both cortisol and cortisone in plasma, saliva, and wool and of cortisol in feces. In plasma, cortisol concentrations were higher than cortisone (P < 0.05), whereas saliva cortisol and cortisone concentrations did not differ significantly. In wool, the concentration of cortisone was about 19-fold higher than that of cortisol during treatment and post-treatment periods. Treatment with HCA inhibited wool growth. These results demonstrate that an increase in glucocorticoids in the blood of sheep is reflected in increases in saliva (after 7 d of treatment), feces (21 d), and wool (14 d). Therefore, measures of glucocorticoids in these matrices may provide a measure of activation of the adrenal glands over time in sheep, thereby providing a retrospective indicator of chronic stress. With respect to wool, it appears that cortisol is predominantly metabolized to cortisone in the skin or wool follicle and is stored as cortisone. Therefore wool cortisone may also provide an important measure in quantifiying chronic stress in sheep.

Comparative proteomics reveals genetic mechanisms underlying secondary hair follicle development in fine wool sheep during the fetal stage

The aim of this study was to investigate the genetic mechanisms underlying wool production by characterizing the skin protein profile and determining the proteomic changes that occur as a consequence of development in wool-producing sheep using a label-free proteomics approach. Samples were collected at four stages during gestation (87, 96, 102, and 138 days), and every two consecutive stages were statistically compared (87 versus 96, 96 versus 102, and 102 versus 138 days). We identified 227 specific proteins in the sheep proteome that were present in all four stages, and 123 differentially abundant proteins (DAPs). We also observed that the microstructure of the secondary follicles changed significantly during the development of the fetal skin hair follicle. The screened DAPs were strictly related to metabolic and skin development pathways, and were associated with pathways such as the glycolysis/gluconeogenesis. These analyses indicated that the wool production of fine wool sheep is regulated via a variety of pathways. These findings provide an important resource that can be used in future studies of the genetic mechanisms underlying wool traits in fine wool sheep, and the identified DAPs should be further investigated as candidate markers for predicting wool traits in sheep. SignificanceWool quality (fiber diameter, length, etc.) is an important economic trait of fine wool sheep that is determined by secondary follicle differentiation and re-differentiation. Secondary follicles of fine wool sheep developed from a bud (87 days), and underwent differentiation (96 days) and rapid growth (102 days) until maturity (138 days) during gestation. Comparative analysis based on differential proteomics of these four periods could provide a better understanding of the wool growth mechanism of fine wool sheep and offer novel strategies for improving fine wool quality by breeding.