Greasy Fleece Weight Research Articles

Identification of SNPs and expression patterns of FZD3 gene and its effect on wool traits in Chinese Merino sheep (Xinjiang Type)

As a member of the Frizzled family, Frizzled3 (FZD3) is a receptor of the canonical Wnt signaling pathway and plays a vital role in mammalian hair follicle developmental processes. However, its effects on wool traits are not clear. The objectives of this study were to identify the single nucleotide polymorphisms (SNPs) and the expression patterns of FZD3 gene, and then to determine whether it affected wool traits of Chinese Merino sheep (Xinjiang Type) or not. PCR-single stranded conformational polymorphism (PCR-SSCP) and sequencing were used to identify mutation loci, and general linear model (GLM) with SAS 9.1 was used for the association analysis between wool traits and SNPs. Quantitative real-time PCR (qRT-PCR) was used to investigate FZD3 gene expression levels. The results showed that six exons of FZD3 gene were amplified and two mutation loci were identified in exon 1 (NC_019459.2: g.101771685 T>C (SNP1)) and exon 3 (NC_019459.2: g.101810848, A>C (SNP2)), respectively. Association analysis showed that SNP1 was significantly associated with mean fiber diameter (MFD) (P=0.04) and live weight (LW) (P=0.0004), SNP2 was significantly associated with greasy fleece weight (GFW) (P=0.04). The expression level of FZD3 gene in skin tissues of the superfine wool (SF) group was significantly lower (P<0.05) than that of the fine wool (F) group. Moreover, it had a higher expression level (P<0.01) in skin tissues than in other tissues of Chinese Merino ewes. While, its expression level had a fluctuant expression in skin tissues at different developmental stages of embryos and born lambs, with the highest expression levels (P<0.01) at the 65th day of embryos. Our study revealed the genetic relationship between FZD3 variants and wool traits and two identified SNPs might serve as potential and valuable genetic markers for sheep breeding and lay a molecular genetic foundation for sheep marker-assisted selection (MAS).

Identification of the Ovine Keratin-Associated Protein 21-1 Gene and Its Association with Variation in Wool Traits.

Simple SummaryKeratin-associated proteins (KAPs) are key constituents of wool and hair fibers. In this study, the ovine keratin-associated protein 21-1 gene (KRTAP21-1) was identified, and association analysis showed that its variation affected wool yield, which prompted the conclusion that the gene may have potential use as a genetic maker for improving wool yield.Keratin-associated proteins (KAPs) are key constituents of wool and hair fibers. In this study, an ovine KAP gene encoding a HGT-KAP protein was identified. The gene was different from all of the HGT-KAP genes identified in sheep, but was closely related to the human KAP21-1 gene, suggesting that it represented the unidentified ovine KRTAP21-1. Four variants (named A to D) of ovine KRTAP21-1 were found in 360 Merino × Southdown-cross lambs from four sire lines. Three sequence variations were detected among these variants. Two of the sequence variations were located upstream of the coding region and the remaining one was a synonymous variation in the coding sequence. Six genotypes were found in the Merino-cross lambs, with only two of the genotypes (AA and AC) occurring at a frequency of over 5%. Wool from sheep of genotype AA had a higher yield than that from AC sheep (p = 0.014), but tended to have a lower greasy fleece weight (GFW) than that of genotype AC (P = 0.078). This suggests that variation in KRTAP21-1 affects wool yield and the gene may have potential for use as a genetic maker for improving wool yield.

Estimation of genetic, heritability, and phenotypic trends for weight and wool traits in Rambouillet sheep

Genetic and phenotypic trends give an indication of the progress of a breed over the years and help in understanding the effectiveness of selection. Therefore, a study was planned to estimate genetic, heritability and phenotypic trends for Rambouillet breed of sheep. Trends were estimated for birth weight, weaning weight, fibre diameter, greasy fleece weight at clip one and staple length on data collected from 1998 to 2008. Two yearly mean phenotypic values, heritability values, and mean breeding values for birth weight, weaning weight, fibre diameter, greasy fleece weight at clip one and staple length were estimated. These trends were determined as a linear regression coefficient of mean breeding values using BLUP (best linear unbiased prediction) for the animal’s year of birth and a trend line was generated separately for each trait. Trends for phenotypic values were positive for birth weight, staple length and greasy fleece weight whereas for weaning weight and fibre diameter, the trends were negative. The slopes for birth weight and weaning were found to be 0.040 ± 0.0525 and −0.07 ± 0.241 respectively. Slopes for fibre diameter, staple length and greasy fleece weight for first clip were -0.011 ± 0.01, 0.146 ± 0.041 and 0.052 ± 0.029 respectively. The slopes all traits were found to be insignificant except staple length. For heritability, the slopes of birth weight, weaning, fibre diameter, staple length and greasy fleece weight for first clip were 0.0005 ± 0.0048, 0.009 ± 0.0048 0.0058 ± 0.011, 0.0041 ± 0.003, and 0.0061 ± 0.0039 respectively. Trends obtained for breeding values were positive for birthweight, staple length and greasy fleece weight for first clip and negative for weaning weight and fibre diameter. All traits had an insignificant slope for breeding values. The slopes for breeding values for birth weight and weaning were 0.001 ± 0.0004 and −0.0025 ± 0.001 respectively. Slopes for fibre diameter, staple length and greasy fleece weight for first clip were −0.0002 ± 0.0002, 0.0002 ± 0.0001, 0.0001 ± 0.0002 respectively. It is concluded that an optimal selection strategy that considers both genetic merits and coancestry of mates (in order to avoid close breeding and inbreeding depression) should be adopted to sustain the sheep breeding programs in the State.

Nucleotide variation in the ovine KRT31 promoter region and its association with variation in wool traits in Merino-cross lambs

AbstractKeratins are the main structural proteins of wool fibres, and it is thought that variation in the keratins may affect wool fibre characteristics. Polymerase chain reaction-single stranded conformational polymorphism (PCR-SSCP) analyses were used to investigate four regions of the ovine keratin gene KRT31 including a portion of the promoter, the exon 1, exon 3 and exon 7 regions. Initially, in a screening panel of 300 New Zealand Romney, Merino and White Dorper sheep obtained from 26 farms, three, two, two and two PCR-SSCP banding patterns were observed for these four regions, respectively. The promoter region, the exon 1 and exon 3 regions contained two single nucleotide polymorphisms (SNPs) and the exon 7 region contained one SNP. The effect of the variation found in the promoter region on wool traits was subsequently investigated in 485 Southdown × Merino-cross lambs from seven sire-lines. The three variants identified in the original 300 sheep (named A, B and C) were observed with frequencies of 56, 29 and 15%, respectively. The presence of A and B had no significant effect on wool traits, but the presence of C was found to be associated with an increase in greasy fleece weight (GFW), clean fleece weight (CFW) and mean staple length (MSL). There was an effect of genotype on CFW and MSL, with BC sheep producing wool of higher CFW and MSL than AA, AB, AC and BB sheep. These results suggest that ovine KRT31 might be a useful candidate gene for improving wool traits.

Evaluation of Rambouillet, Polypay, and Romanov-White Dorper × Rambouillet ewes mated to terminal sires in an extensive rangeland production system: body weight and wool characteristics1,2.

Though lamb sales account for the majority of annual receipts on U.S. sheep operations, wool is an important income source for many Western flocks. Crossing fine-wool sheep with prolific or composite hair sheep breeds can increase lamb production, but fleece quality and marketability may be reduced by a greater content of nonwool fibers (e.g., med and kemp). The objectives of this study were to compare BW and wool characteristics of Rambouillet, Polypay, and Romanov-White Dorper × Rambouillet (RW-RA) ewes under extensive rangeland management conditions. Ewe BW was collected before mating (fall) and 30 d postlambing (spring) each year from 1 yr up to 4 yr of age. In spring and fall, Rambouillet and Polypay ewes were similar in BW (P ≥ 0.94). Spring BW did not differ (P = 0.13) between RW-RA and Polypay, but Rambouillet ewes were heavier than RW-RA in the spring (P = 0.02). Both Rambouillet and Polypay ewes were heavier (P < 0.07) than RW-RA in the fall. Greasy fleece weight and mid-side wool samples were collected from ewes at 1 and 4 yr of age. Clean fleece weights (CFW) were estimated from average laboratory scoured yield of mid-side wool samples composited within-breed. Average fiber diameter (AFD), SD of fiber diameter (SD-FD), and percentage med (%M), kemp (%K), and total medullated fibers (%T) were quantified on individual mid-side wool samples. There was no difference in 1-yr-old CFW among breed types (P ≥ 0.96). Four-yr-old Rambouillet ewes had heavier CFW (2.29 kg; P < 0.001) than 4-yr-old Polypay (1.83 kg) and RW-RA ewes (1.86 kg), which were not different (P > 0.99). Within 1- and 4-yr-olds, AFD differed among breed type (P < 0.001) and was the finest for Rambouillet (20.1 and 21.9 µm, respectively), intermediate for RW-RA (22.8 and 24.8 µm), and coarsest for Polypay (24.2 and 26.7 µm). Also within 1- and 4-yr olds, SD-FD was lowest in Rambouillet, intermediate in Polypay, and greatest in RW-RA (P < 0.01). Wool from RW-RA ewes had greater %M, %K, and %T (P < 0.001) than wool from Rambouillet and Polypay ewes, which were not different (P > 0.99). Results indicated superior wool production for Rambouillet compared with the coarser, more variable wool produced by Polypay and RW-RA. Still, past research reported greater lamb production in Polypay and RW-RA ewes which, under recent market conditions, would be associated with greater annual gross revenue for these breed types than for Rambouillet.

Genetic parameters for medullated fiber and its relationship with other productive traits in alpacas

The alpaca fiber diameter (FD) varies from 18 to 36 μm, being the finer fiber categories highly appreciated. However, the alpaca fiber presents some limitations in the textile industry due to the high incidence of fiber medullation and diameter variability, both reduces the comfort feeling of the garments. Decreasing or even removing medullation could be a possible selection objective in alpaca breeding programs for increasing economic value of the alpaca fiber. Therefore, the present work aimed to estimate genetic parameters regarding medullation traits, as well as the genetic correlations with other economical important traits, to be able to select the appropriate criteria to reduce or remove medullation on alpaca fiber and help to reduce the prickle factor in the garments. The data was collected from 2000 to 2017 and belonged to the Pacomarca experimental farm. There were 3698 medullation records corresponding to 1869 Huacaya and 414 Suri genetic types. The fiber samples were taken from the mid side, and were analyzed in an OFDA 100® device. The traits analyzed were percentage of medullation (PM), medullated fiber diameter (MFD), FD, standard deviation of FD, greasy fleece weight as fiber traits; density, crimp in Huacaya and lock structure in Suri, head conformation, leg coverage as morphological traits; weaning weight and age at first calving as secondary and functional traits. Genetic parameters were estimated via a multitrait restricted maximum likelihood. The heritabilities for PM and MFD were 0.225 and 0.237 in Huacaya genetic type and 0.664 and 0.237 in Suri genetic type, respectively; heritabilities for other traits were moderate for productive and morphological traits, and low to moderate for secondary and functional traits. The genetic correlations PM–FD and MFD–FD were high and favorable in both genetic types, between 0.531 and 0.975; the genetic correlation PM–MFD was 0.121 in Huacaya and 0.427 in Suri. The rest of genetic correlations with other traits were in general moderate and favorable. The repeatabilities were 0.556 and 0.668 for PM, and 0.322 and 0.293 for MFD in Huacaya and Suri genetic types, respectively. As a conclusion, PM was identified to be a good selection criterion, probably combined in an index with FD to reduce prickling factor.

Associations between variation in the ovine high glycine-tyrosine keratin-associated protein gene KRTAP20-1 and wool traits.

The keratin-associated proteins (KAPs) are important constituents of wool fibers. Of the many mammalian KAP genes (KRTAPs) identified, KRTAP20-1 has been described in humans, but it has not been described in any other species. A search of the sheep genome using the human KRTAP20-1 sequence revealed a homologous open reading frame on chromosome 1, which would encode a high glycine-tyrosine KAP. PCR-single-stranded conformational polymorphism (PCR-SSCP) analysis identified 8 different banding patterns representing 8 unique DNA sequences (named A to H). The sequences had highest similarity to the human KRTAP20-1 sequence, and this suggests that they are variants of ovine KRTAP20-1. Among these variants, a 12-bp insertion/deletion and 6 single nucleotide poly- morphisms (SNPs), including one 5' untranslated region (UTR) SNP, one 3' UTR SNP, and 2 nonsynonymous SNPs, were detected. Variant A was found to be associated with a decrease in mean fiber diameter, fiber diameter standard deviation, and prickle factor, whereas variant C was associated with increased greasy fleece weight and decreased wool yield. These associations persisted after adjusting for the effect of 2 nearby KRTAPs (KRTAP6-3 and KRTAP22-1) that have also been reported to associate with these wool traits. This suggests that variation in KRTAP20-1 affects wool yield and mean fiber diameter-associated traits, and that this effect is unlikely to be the result of the clustering of these KRTAPs on chromosome 1.

Tenascin-XB (TNXB) amino acid substitution E2004G is associated with mature weight and milk score in American Rambouillet, Targhee, Polypay, and Suffolk sheep

Sheep are economically important worldwide, and growth-associated genetic variants, such as a TNXB charged amino acid substitution E2004G and a silent DGAT1 single nucleotide polymorphism (rs409119650), could improve sheep profitability. However, both were identified in single reports using small groups of sheep from outside the U.S. We evaluated 896 U.S. sheep from one location to investigate an association of TNXB E2004G and DGAT1 rs409119650 with growth and lifetime production. For TNXB E2004G, glutamic acid homozygotes had greater body weights in spring and fall at ages 3 and 4 (all P ≤ 0.05) and greater milk scores at ages 3 and 4 (P < 0.05). These data provide the first report of an association with milk score and confirm a prior report showing association of the ancestral glutamic acid allele with increased growth. While DGAT1 rs409119650 was associated with increased 4-year-old body weight and lifetime greasy fleece weight (P < 0.05), these results should be interpreted with caution given a low minor allele frequency (4.9%). Overall, confirmation that TNXB E2004G is associated with increased mature weight in divergent breeds and multiple countries may suggest a useful role in selective breeding programs.

EFFECT OF WATER AND FEED SALINITY ON COAT COVER TRAITS OF BARKI SHEEP IN SOUTH SINAI

Twenty nine Barki sheep ewes (2-3 years old) were randomly assigned into four groups (7, 7, 8 and 7 animals for group 1, 2, 3 and 4, respectively) to investigate the impact of salinity in both water and feed on some wool fiber traits (greasy fleece weight; GFW, fibre diameter; FD, staple length; STL, fibre length; FL and fibre type ratios; FTR) and skin follicles characteristics (secondary to primary follicles ratio; S/P ratio) in addition to triiodotyronine; T3 and thyroxin; T4 hormones under semi-arid condition of South Sinai, Governorate, Egypt. Ewes of group 1 (G1) were served as control and fed on berseem hay and drink tap water. Ewes of group 2 (G2) were fed on berseem hay and drink saline water, while ewes of group 3 (G3) and group 4 (G4) were fed on salt-tolerant plants and drink either tap water or saline water, respectively. Results of the present study showed the high variability of both fibre lengths and fibre type ratios compared to the other traits. Type of ration had a significant (P Ewes in G1 had higher GFW and S/P ratio, longer coarse fibres (FL) and smaller FD than ewes in the other groups. However, differences among groups were not significant in the case of fibre type ratios, FL (fine fibres) and kemp. Ewes in both G2 and G4 showed the lighter GFW and the shorter SL compared to their partners in the other two groups. In conclusion, results indicated that Barki sheep are tolerant to both drinking saline water and feeding on salt tolerant plants although there was decreased in greasy fleece weight and staple length with slightly increases in fibre diameter.

Polymorphism of keratin-associated protein (KAP) 7 gene and its association with wool traits in Rambouillet sheep

In the present study, association of polymorphic variants of KAP 7 gene with wool traits in Rambouillet sheep was investigated by using SSCP-PCR. Genomic DNA was isolated from blood samples of 100 Rambouillet sheep. A 388 bp segment was amplified by PCR using ovine specific primers for KAP 7 gene. The results identified 3 genotypes, viz. AA, AB and BB with genotype frequencies of 0.340 (34), 0.270 (27) and 0.390 (39) respectively and allele frequencies of 0.475 for allele A and 0.525 for allele B. The χ²-test showed that the genotype distribution was not in agreement with Hardy-Weinberg equilibrium (HWE). KAP 7 gene has significantly higher clean wool yield and greasy fleece weight in males whereas females have significantly superior fibre diameter, higher staple length and wool count. BB genotype has significantly higher staple length followed by AA and AB genotype. BB genotype has significantly higher greasy fleece weight production followed by AB and least by AA genotype. From the study, it may be concluded that KAP 7 gene might be a potential molecular marker for genetic selection for higher staple length and greasy fleece weight in Rambouillet sheep.

Machine learning approaches for early prediction of adult wool growth and quality in Australian Merino sheep

Wool production and its quality play important roles in determining the total income received by Australian sheep producers. Enabling accurate and early prediction of wool production and quality traits for individual and groups of sheep can provide useful information assisting on-farm management decision-making. Robustness and high performance of modern prediction methods, namely Machine Learning (ML) algorithms, make them suitable for this purpose. In this research, flock specific environmental data and phenotypic information of yearling lambs were combined to identify the most effective algorithm to predict adult Greasy Fleece Weight (aGFW), adult Clean Fleece Weight (aCFW), adult Fibre Diameter (aFD), adult Staple Length (aSL), and adult Staple Strength (aSS). Algorithms were evaluated and compared in terms of prediction error, the correlation between predicted and actual phenotype in a test set, and for uncertainty in prediction.Artificial Neural Networks (NN), Model Tree (MT) and Bagging (BG) were used to carry out these predictions and their performance was compared with Linear Regression (LR) as the gold standard of prediction. The NN method had the poorest performance in all five traits. MT and BG had very similar performance and for a number of practical reasons, our method of choice was MT for early prediction of adult wool traits. The correlation coefficients of MT predictions were 0.93, 0.90, 0.94, 0.81 and 0.59 with Mean Absolute Error of 0.48 kg, 0.41 kg, 0.92 µm, 6.91 mm and 6.82 N/ktex, for predicting aGFW, aCFW, aFD, aSL, and aSS respectively.

Estimation of Breeding Values and Genetic Trend of Production Traits in Munjal Sheep

Munjal is a new promising breed of sheep and is popular among farmers for its big size and faster growth rate. The data pertaining to the production traits of 462 Munjal sheep sired of 27 rams were used to evaluate the sire by estimating the breeding value using Best Linear Unbiased Prediction (BLUP) method. The average breeding value of Munjal sires for Birth weight (BW), Weaning weight (WW), Six month body weight (SMW), One year body weight (YW) and Greasy fleece weight (GFW) were estimated as 4.15, 15.57, 21, 26.54 and 1.83 Kg, respectively. After estimation of breeding values, the sires were ranked as per their genetic merit. The product moment correlations between sire’s estimated breeding values among production traits were low to high ranging from 0.01 to 0.80. The rank correlations of BW with WW, SMW, YW and GFW were low and positive. The rank correlations of WW with SMW and YW were high, positive and significant. High and positive estimates indicate that there is high degree of similarity between ranking of WW with SMW and YW. The rank correlation of SMW with YW was high, positive and significant and indicated that there is high degree of similarity between rankings of SMW with YW. Genetic trends for BW, WW, SMW, YW and GFW were estimated by regressing breeding values of traits on year of the birth of the animals and were obtained as -0.09, -0.25, -0.51, -0.67 and -0.01 kg/ year, respectively. Phenotypic trend for BW, WW, SMW, YW and GFW were estimated by phenotypic value of the traits on year of the birth of the animals were obtained as 0.08, -0.33, -0.44, -0.59 and -0.04 Kg/year, respectively. Genetic trend obtained in the present study were in negative direction which might be due to inbreeding because of small flock size.

Estimation of genetic parameters for production traits in Munjal sheep

Astudy was carried out to estimate the genetic parameters of production traits in Munjal sheep using 16 years (2001–2016) data of 462 sheep maintained at Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar Mixed model analysis included the sire as a random effect and effects of period of birth, sex, dam's age at lambing as fixed effects. Heritability estimates and genetic correlations for different traits were calculated by paternal half-sib correlation method using sire components of variance and covariance. Period of birth and sex of lamb had significant effect (P<0.05) on all traits except greasy fleece weight (GFW). Dam's age at lambing had significant (P<0.05) effect only on birth weight. The overall least squares means of production traits recorded for birth weight (BW), weaning weight (WW), six months body weight (SMW), yearling body weight (YBW) and annual GFW were 4.1±0.07, 15.57±0.22, 20.79±0.53, 26.40±0.41 and 1.84±0.04 kg, respectively and the corresponding heritability estimates were 0.35±0.18, 0.48±0.20, 0.57±0.24, 0.48±0.25 and 0.52±0.22, respectively. Genetic correlations among production traits were positive and low to high in magnitude (0.10±0.05 to 0.76±0.05) and the highest genetic correlation of 0.76±0.05 was found between SMW and YBW. Phenotypic correlations among various production traits were found to be positive and significant ranging from 0.17±0.04 to 0.81±0.03. It was concluded that selection on the basis of SMW would be the best approach to improve growth performance in Munjal sheep as the trait has high heritability and positive genetic correlation with other body weights.

EFFECT OF BREED, BODY CONDITION SCORE AND AGE ON SOME ECONOMIC TRAITS OF LOCAL FLOCKS EWES

This study aimed to estimate the effect of breed, Body Condition Score (BCS) and age on some economic traitsof local flock’s ewes. The ewes studied in the present investigation represent three local breeds (53 karadi, 44 Awassi and 47 Mamesh) bred in Erbil plain during the period from January/ 2009 to June /2010.The results showed a highly significant breed effect (p <0.01) on all the studied traits. Mamesh ewes surpassed both Karadi and Awassi ewes in milk yield (102.269, 88.254 and 92.684 kg), respectively, besides the lambs of the same breed were superior in birth weight (4.885kg) and weaning weight (27.612kg) compared with karadi and Awassi lambs. Greasy fleece weights of the Karadi, Awassi and Mamesh ewes were 2.220, 1.829 and 2.585kg respectively. The superiority of Mamesh ewes were found to be highly significant (p <0.01). The study also revealed that the (BCS) exerts an important effect on milk yield, greasy fleece weight and birth weight. Ewes with (BCS) 4 showed a higher milk yield (102.883kg) as comparing with ewes having (BCS) 3(95.083kg) and that having (BCS) 2 (86.391kg) .Correlation coefficient highly significant (p <0.01) between birth weight and milk yield was 0.32and between birth weight and weaning weight was 0.38and between ewes body weight and greasy fleece weight was 0.43.

Polymorphism of KRT83 and its association with selected wool traits in Merino-cross lambs

Keratins are structural proteins in the cortex of wool fibres. It is thought that variation in the keratin genes (KRTs) affects wool structure and characteristics. Polymerase chain reaction-single stranded conformational polymorphism (PCR-SSCP) analysis was used to investigate three regions of ovine KRT83. These regions were a portion of the promoter, the exon 2 region (including part of intron 1) and a region encompassing exon 3-4 (including all of exon 3, intron 3, exon 4 and part of intron 4). Initially, in 300 New Zealand Romney, Merino and White Dorper sheep obtained from 26 farms, one, two and four PCR-SSCP banding patterns were observed for these regions respectively. The exon 2 region contained two single nucleotide polymorphisms (SNPs) and the exon 3-4 region contained five SNPs. Investigation of the effect of the variation in the exon 3-4 region on variation in some wool traits were subsequently undertaken in 489 Merino×Southdown-cross sheep from seven sire-lines. The four variants identified in the original 300 sheep (designated A-D) and a new variant (E containing a new SNP) were observed with a frequency of 64.6%, 15.4%, 6.6%, 10.1% and 3.3%, respectively. General linear mixed-effects models (GLMMs) were used to investigate associations between the presence or absence of the variants and the wool traits, with a second set of models testing associations between common genotypes and those traits. The presence of A was associated with a decrease in fibre diameter standard deviation (FDSD) and coefficient of variation of fibre diameter (CVFD). The presence of C was associated with an increase in mean fibre diameter (MFD), mean fibre curvature (MFC) and prickle factor (PF), and a decrease in wool yield (Yield) [clean fleece weight (CFW)/greasy fleece weight (GFW)×100%]. A trend for association between the presence of C and increased FDSD was also detected. The presence of D was associated with an increase in MFD and PF, and a decrease in Yield. The presence of E was associated with a decrease in CVFD. Genotype AD had a higher GFW and a lower Yield than AA, and AC and AD tended to have increased MFD compared to AA and AB. These results suggest that ovine KRT83 might be a useful candidate gene for improving wool traits.

Detection of QTL for greasy fleece weight in sheep using a 50K single nucleotide polymorphism chip.

Genome-wide association studies (GWAS) have introduced an influential tool in the search for quantitative trait loci (QTL) influencing economically important traits in sheep. To identify QTL associated with greasy fleece weight, a GWAS with 50K single nucleotide polymorphisms (SNPs) was performed in a Baluchi sheep population. Association with greasy fleece weights was tested using the software Plink. The results of our GWAS provided three novel SNP markers and candidate genes associated with greasy fleece weight. A total of three chromosome-wide significant associations were detected for SNP on chromosomes 17 and 20 affecting greasy fleece weight across the four shearing. One of the significant SNP markers was located within ovine known genes namely FAM101A. Further investigation of these identified regions in validation studies will facilitate the identification of strong candidate genes for wool production in sheep.

A Study of Some Wool Traits of Barki Sheep Fed on Nigella sativa Cake under Desert Conditions

This study was conducted at Maryout Research Station, Desert Research Center (33 km south west of Alexandia), toinvestigate the effect of feeding Nigella sativa cake (NSC) as a protein source on wool production and characteristics ofthe growing male Barki lambs under the semi-arid conditions.Twenty one growing male Barki lambs (3 months) weighing 22.90 kg were used in this study, from weaning up tosexual maturity (300 days). Animals were randomly distributed to three equal groups with seven lambs each. The firstgroup was fed on concentrate feed mixture (CFM) containing 35% undecorated cotton seed meal (CSM) and served as acontrol group. The second (G2) and third (G3) groups were fed on the same concentrate mixture in which the proteinsource was partially replaced by 5 and 10 % of NSC, respectively.The results revealed that using Nigella sativa cake as an alternative protein source at levels of 5% (G2) and 10% (G3)significantly improved final body weight, daily gain, greasy fleece weight and clean wool yield. It also improved (P<0.01)wool traits that including staple length, staple strength, point of staple break and staple elongation rate. Wool bulk andresilience were also improved by the two levels of NSC as both traits are considered as indicators for wool qualityaffecting carpet manufacture.

CRISPR/Cas9-mediated loss of FGF5 function increases wool staple length in sheep.

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.

Ectopic expression of FGF5s induces wool growth in Chinese merino sheep

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.

Influence of environmental factors on production traits and heritability estimates of magra sheep in Arid region

The aim of the present study was to examine the effect of non-genetic factors on growth and wool traits of 1482 Magra sheep spread over a period of five years (2008–12) maintained at the Arid Region Campus, ICAR-Central Sheep and Wool Research Institute, Bikaner. The least squares means for body weight at birth, 3, 6, 9 and 12 months of age were 3.18±0.02, 16.12±0.14, 23.72±0.20, 28.37±0.21 and 31.88±0.25 kg, respectively. The average daily gain in body weights during 0–3, 3–6 and 6–12 months of ages were 143.45±1.43, 84.23±1.35 and 40.22±1.13 g, respectively. For greasy fleece weight at first, second and third clips, least squares means were 567.18±5.16, 628.08±4.97 and 640.01±5.45 g, respectively. Least squares analysis of variance revealed significant (P<0.01) effect of year of birth and sex on all the traits. The fixed effect of parity had significant (P<0.01) effect only on birth weight. Dam's weight at lambing was a significant (P<0.01) source of variation for all the body weight traits, except average daily gains during 3–6 and 6–12 months of age. Greasy fleece weights at first, second and third clips were affected significantly (P<0.01) by lamb's age at shearing. Heritability estimates for body weight at birth, 3, 6, 9 and 12 months of age and average daily gain during 0–3, 3–6 and 6–12 months of age and greasy fleece weight at first, second and third clips were 0.17±0.06, 0.31±0.08, 0.33±0.09, 0.35±0.10, 0.59±0.14, 0.28±0.08, 0.23±0.07, 0.62±0.14, 0.52±0.11 and 0.32±0.10 and 0.11±0.09, respectively. Heritability estimates for all the growth traits was moderate to high, suggesting further scope for genetic improvement in the flock.