Fleece Weight Research Articles

Combined genomic evaluation of Merino and Dohne Merino Australian sheep populations.

The Dohne Merino sheep was introduced to Australia from South Africa in the 1990s. It was primarily used in crosses with the Merino breed sheep to improve on attributes such as reproduction and carcass composition. Since then, this breed has continued to expand in Australia but the number of genotyped and phenotyped purebred individuals remains low, calling into question the accuracy of genomic selection. The Australian Merino, on the other hand, has a substantial reference population in a separate genomic evaluation (MERINOSELECT). Combining these resources could fast track the impact of genomic selection on the smaller breed, but the efficacy of this needs to be investigated. This study was based on a dataset of 53,663 genotypes and more than 2 million phenotypes. Its main objectives were (1) to characterize the genetic structure of Merino and Dohne Merino breeds, (2) to investigate the utility of combining their evaluations in terms of quality of predictions, and (3) to compare several methods of genetic grouping. We used the 'LR-method' (Linear Regression) for these assessments. We found very low Fst values (below 0.048) between the different Merino lines and Dohne breed considered in our study, indicating very low genetic differentiation. Principal component analysis revealed three distinct groups, identified as purebred Merino, purebred Dohne, and crossbred animals. Considering the whole population in the reference led to the best quality of predictions and the largest increase in accuracy (from 'LR-method') from pedigree to genomic-based evaluations: 0.18, 0.14 and 0.16 for yearling fibre diameter (YFD), yearling greasy fleece weight (YGFW) and yearling liveweight (YWT), respectively. Combined genomic evaluations showed higher accuracies than the evaluation based on the Dohne reference only (accuracies increased by 0.16, 0.06 and 0.07 for YFD, YGFW, and YWT, respectively). For the combined genomic evaluations, metafounder models were more accurate than Unknown Parent Groups models (accuracies increased by 0.04, 0.04 and 0.06 for YFD, YGFW and YWT, respectively). We found promising results for the future transition of the Dohne breed from pedigree to genomic selection. A combined genomic evaluation, with the MERINOSELECT evaluation in addition to using metafounders, is expected to enhance the quality of genomic predictions for the Dohne Merino breed.

Genetic improvement and conservation of goats in tropic

Goats indeed have a significant historical and contemporary importance in human civilization, particularly in the realm of agriculture and food production. Their adaptability and widespread distribution have made them crucial for various societies across the world. Goats have played a central role in the Neolithic agricultural revolution, aiding in the spread of human civilization globally. Their adaptability allowed them to thrive in diverse environments, contributing to the sustenance and expansion of human settlements. Goats are highly adaptable and are found in a wide range of geographical regions. Their presence spans across continents, from tropical to temperate climates, showcasing their ability to thrive in various environmental conditions. There is diversity in the production performance of goats based on the region of the world and the specific breeds. Genetic improvement programs aim to enhance economically important traits such as milk production, growth rates and fiber production, thereby increasing productivity and income for goat farmers. Understanding the genetic parameters such as heritabilities and repeatabilities for various traits is crucial for designing effective breeding programs. These parameters provide insights into the genetic potential of goats for traits like milk production, growth and fiber quality. Heritability estimates for reproductive traits, body weight, daily gain and direct and maternal heritability are important for implementing selective breeding strategies aimed at improving overall productivity and efficiency in goat farming. Genetic improvement programs have been implemented in tropical environments to enhance milk production traits in goats. Genetic improvements have also targeted fiber production in goats, with a focus on traits such as grease fleece weight and average fiber diameter. These efforts aim to enhance the quality and quantity of fiber produced by goats for various commercial purposes. Despite the importance of conserving goat breeds with unique characteristics, planned conservation programs in tropical regions are often neglected. It’s emphasized that preserving indigenous goat breeds in their native habitats is essential for maintaining genetic diversity and ensuring future resilience in goat farming.

Variation in the Exon 3-4 Region of Ovine KRT85 and Its Effect on Wool Traits.

α-keratins are structural proteins in the cortex of wool fibres and assemble in an organized fashion into keratin intermediate filaments. Variation in these keratin proteins affects the structure and characteristics of wool fibre, making keratin genes ideal candidates for the development of gene markers that describe variations in wool traits. A region of KRT85 spanning exon 3-4 (including the entire exon 3, intron 3, exon 4 and part of intron 4) was investigated. Two banding patterns defining two variant sequences (A and B) were observed in this region, and these were characterised by the presence of two single nucleotide polymorphisms. The effect of this variation in the exon 3-4 region of KRT85 on wool traits was investigated in 463 Merino × Southdown-cross lambs. The frequencies of these two variants in these sheep were 55.6% and 44.4%, respectively. Three different genotypes were observed with frequencies of 32.6%, 46.1% and 21.3% for AA, AB and BB, respectively. The presence of A was associated with an increase in greasy fleece weight and clean fleece weight, while the presence of B was associated with an increased wool prickle factor. These findings should be replicated in a broader range of sheep breeds to determine whether the associations are robust and to clarify whether the observed effects are attributable to breed differences or to gene effects themselves.

THE EFFECT OF SUB-CLINICAL INFECTION WITH HAEMONCHUS CONTORTUS ON PRODUCTION PERFORMANCE IN THE ‎PREGNANT EWES

Fourteen Bulgarian pregnant ewes (three months of gestation), were used and divided in two groups, one group was inoculated with 500 infective larvae /kg. body weight, the other group remained non-infected control. Productive parameters, blood changes were recorded and faecal egg counts were examined weekly. Marked reduction in food intake was recorded in infected ewes, especially during prelambing period. No obvious differences were noted between both groups after lambing. Slight differences in body weight gain were recorded between both groups until labour, while after lambing, the weight losses of infected ewes were highly significant 1%. No effect of infection has been seen on fleece weight, while significant depression in the haemoglobin and packed cell volum of infected group during the pre-parturient period, and the high reduction occured at week (7). Generally the results indicated that there were variations in resistance of ewes or its susceptibility to parasitic infection.

Examining across year genotype by environment interactions for production and reproduction traits in Merino sheep

Variation in feed resource availability within production systems can cause genotype by environment interactions that change the ranking of the best animals to select between environments. Mediterranean environments have high variation in pasture growth between years that could cause genetic by environment interactions for sheep production traits. Therefore, we estimated heritabilities for live weight, fleece weight, fibre diameter and number of lambs weaned in six years from 2000 to 2005 and correlations between years comparing multivariate analysis and random regression analysis. We compared 3 methods: 1 multivariate analysis estimating (co)variances for traits in each year, 2 Random regression estimated (co)variances for intercept and slope for traits as repeated measurements fitted against average pasture growth in each year and 3. Random regression fitted against corrected average performance of animals in each year. Random regression was estimated with an order of polynomial of one for additive genetic variance and zero for permanent environmental effects. This combination of polynomials was the best fit based on Bayesian information criterion. We estimated heritabilities for each year and correlations between years using records from 3299 pedigreed Merino ewes managed at Katanning in Western Australia. There were 4651 records for adult live weight, 6750 for adult clean fleece weight, 6965 for adult fibre diameter, and 7774 for number of lambs weaned across all 6 years. Number of lambs weaned had more genotype by environment interactions than other traits, with fibre diameter and fleece weight having genotype by environment interactions between only a few years. Based on Bayesian information criterion values, multivariate analysis fit the data better for live weight, fleece weight and fibre diameter. Additionally, random regression estimated higher genetic correlations between years than multivariate analysis suggesting there was not enough flexibility in the random regression analysis, which used only first order polynomials, to fit differences between years. Pasture growth across years did not explain differences in performance for traits across years. Therefore, for number of lambs weaned, random regression using corrected average performance was a better fit than average pasture growth. For other traits, more years or a better indicator of variation in performance within and between years are required to use random regression for genotype by environment interactions.

Ovine KRT81 Variants and Their Influence on Selected Wool Traits of Commercial Value.

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.

Evaluation and use of recently introduced sheep breeds to Uruguay

Sheep numbers in Uruguay have declined over the last 30 years. In the north and northeast there are extensive wool and dual-purpose systems, respectively, where both wool and meat impact on income. In the south, small-scale family sheep meat production systems have flourished. In this thesis I report work pertaning to production systems in the south (1) and northeast (2) regions. Corriedale (C) is the predominant breed in the country. Milchschaf (M) has been disseminated in the south but C still prevails in the northeast. There is a paucity of rigorous evaluations of these breeds or alternatives that could be more profitable, such as Highlander (H) for the south and Dohne Merino (DM) for the northeast. I experimentally assessed: in 1), wool production, reproduction and growth in C, H and M, and in 2), wool quality and body traits in ewe hoggets from rotational crossbreeding between C and DM. In 1), wool production was better in C, but H and M outperformed C in live weight and reproductive performance. In 2), genotypes with greater proportions of DM produced lower fleece weight, and those with greater proportions of C produced coarser fibre diameter, with no differences in wool quality or morphological traits related to meat aptitude. Gross margins (GM) integrate physical performance with product values and costs, allowing monetary comparison between genotypes. I calculated GMs for a number of production and market scenarios. In 1), most often GM was greatest for H, followed by M. The differences in favor of H and M over C decreased when I considered higher feed requirements for H and M. The GM of H and M increased by assuming they were wool-less (the cost of harvesting exceeds the value of the wool produced). In 2), I considered low and high prices for wool of different fibre diameter. GM was greatest for ¾DM and ⅝DM at low prices, and for ¾DM and ½DM at high prices. C had the lowest GM in all scenarios. I recommend H for southern systems and research on hair sheep breeds. In extensive dual-purpose systems, rotational crossbreeding between C and DM allows for improved wool income without losing meat potential. I formulate recommendations about future genotype evaluations, integrating them with current within breed genetic evaluations.

78 Estimates of genetic parameters for weight, wool, and carcass traits of Rambouillet sheep

Abstract The Rambouillet sheep breed is the foundation to most western range sheep in the U.S. Through the National Sheep Improvement Program (NSIP), Rambouillet breeders seek to improve economically relevant traits. However, the parameters used in the NSIP genetic evaluation were last estimated two decades ago. Our aim was to re-estimate genetic parameters for body weight (BW), carcass, and wool traits. Data were provided by NSIP, which included BW at birth (BWT; n = 28,817), weaning [WWT; n = 5,633; age: 68 (SD 16) day], early post-weaning [PWTE; n = 23,303; 128 (SD 22) d], late post-weaning [PWTL; n = 7,689; 201 (SD 45) d] and as yearlings [YWT; n = 5,830; 375 (SD 33) d]. Yearling ultrasound scans of 12th rib backfat depth (YCF; n = 2,447) and eye muscle depth (YEMD; n = 2,457) were also available. Yearling wool traits were fiber curvature (YFC; n = 6,009), fiber diameter (YFD; n = 9,880), fiber diameter coefficient of variation (YFDCV; n = 8,803), greasy fleece weight (YGFW; n = 11,859) and staple length (YSL; n = 11,270). The pedigree consisted of 36,297 individuals. Animals with phenotypic records were progeny of 333 sires and 1,727 dams. A succession of univariate animal models was fitted. The most comprehensive model included direct and maternal additive genetic effects, their genetic covariance, and maternal permanent environmental and residual effects. Phenotypes were pre-adjusted for birth-rearing type category and, as covariates, dam age and age at recording. Contemporary group—a concatenation of flock, year, season, management group, sex, and, excluding BWT, recording date—was the only fixed effect fitted in the model. Model selection was based on the log-likelihood ratio test, and Akaike and Bayesian information criteria. The data structure, namely dams and their daughters and granddaughters contributing data, allowed reliable testing of the maternal effect terms. The direct-maternal genetic covariance did not explain variation for any trait (P > 0.18). The most parsimonious model for BW traits included direct and maternal additive genetic, and maternal permanent environmental, effects. For carcass and wool traits, only direct additive genetic effects were included in the final model. Such was unsurprising, as maternal effects often diminish as animals age. For the final models fitted (Table 1), direct heritabilities (± SE) for body weights ranged from 0.14 ± 0.01 (BWT) to 0.38 ± 0.04 (PWTL); the maternal heritabilities ranged from 0.04 ± 0.02 (PWTL; YWT) to 0.13 ± 0.01 (BWT). For carcass traits, direct heritabilities were 0.13 ± 0.04 (YCF) and 0.31 ± 0.05 (YEMD). For wool traits, they ranged from 0.37 ± 0.02 (YSL) to 0.58 ± 0.02 (YFD). These re-estimated parameter values are consistent with those used by NSIP, with the exception of PWTL (greater) and YSL (lower). With genomic data accumulating in Rambouillet, further refinements in parameter estimation are planned.

Caracterización del ovino criollo en las comunidades del distrito de Lambrama (Apurímac, Perú)

The study was carried out with Creole sheep in flocks from the communities of Cruzpata and Siusay, both in the Lambrama district, Apurímac, Peru. The study aimed to characterize its productive capacity for meat and wool. Samples were taken from 60 sheep from two flocks to determine live weight, carcass weight, carcass yield, fleece weight and lock length. In addition, using 187 sheep from six flocks from the same area, samples of rib wool (10 g) were taken for analysis using OFDA 2000 equipment. The phenotype of the Creole sheep presents an angular body covered with fleece of various colours; bare face, belly and long legs, which grazes the puna, in an extensive system and without technical support from the State. Live weight, carcass weight and carcass yield are low, mainly affected by age, with variations like what occurs in other places in the mountains; Measurements of fleece weight and lock length are affected by age and sex, and by the lack of periodic shearing. The textile characteristics of the wool show medium fineness, with high variability, with relatively high comfort and spinning fineness indexes; better on the fleece of two-toothed females. The most important correlations were between fibre diameter (DM) and comfort factor (FH) (r=-0.5925); between DM and fineness of yarn (FH) (r=0.5857) and between FC and FH (r=-0.8767), which would indicate that the wool from the Lambrama area is of good quality for the textile industry.

Polymorphism of growth hormone (GH) gene and its association with performance and body conformation of Harnali sheep.

The present study was carried out to study the polymorphism in the GH gene and its association with various performance and body conformation traits, viz., birth weight (B-WT), weaning weight (W-WT), six-month body weight (6M-WT), one-year body weight (Y-WT), annual greasy fleece weight (AGFW), body length (BL), body height (BH), heart girth (HG) and paunch girth (PG) in 138 Harnali sheep. PCR-RFLP was performed to identify polymorphism in the targeted region of the GH gene. The PCR product of 422bp size of the GH gene was amplified encompassing partial exon 2 and inton 3 in Harnali sheep. The PCR product was digested with HaeIII restriction enzyme for the detection of Single nucleotide polymorphism (SNP). The digested products revealed the presence of two genotypes, i.e. AA and AB in the studied population. A > G mutation (A781G) was observed in our resource population. The AA genotype was found to be the predominant genotype (0.62). Chi square value revealed that resource population was not under Hardy-Weinberg equilibrium with respect to target locus. Period of birth was found to have significant effect on W-WT, Y-WT, BL, BH and PG. Sex of animal was found to have significant (P < 0.05) effect on W-WT and highly significant (P < 0.01) effect on 6M-WT, Y-WT and AGFW in Harnali sheep. The effect of genotype was found to be significant (P < 0.05) on annual greasy fleece weight. AB genotype was found to be associated with higher annual greasy fleece weight and can be used as a potential candidate marker in selection criteria for improving greasy fleece weight in Harnali sheep.

Effect of pre-and post-partum feed supplementation of Maraz does on the productive performance of their offspring

The purpose of this experiment was to investigate the impact of maternal pre-and post-partum feed supplementation, under farm conditions, on goat kid's growth, follicle traits and fiber production. The design of experiment was supplementation from 2 months pre-partum to 2 months post-partum with 3 nutritional groups (8 does each). The first does group (GI) was fed black barley at 250 g/doe/day (traditional farmer’s practice), whereas does of the second (GII) and third (GIII) groups were fed concentrate diet at 500 and 750 g/doe/day, respectively. Results revealed that birth weight from GII and GIII was significantly (P&lt;0.05) higher by 22% (2.3 vs. 1.8 kg) than that of GI. Weaning weight and marketable live weight traits, growth rates, follicle traits except primary follicles, and fiber characteristics were significantly (P&lt;0.05) higher in (GIII) followed by (GII) and then (GI). Moreover, goat kids of the GIII attained significantly (P&lt;0.05) 37% (16.9 vs. 10.7 kg) and 26% (16.9 vs. 12.5 kg) more marketable live weight compared with GI and GII, respectively. Also, goat kids of the GIII produced 32% (813.3 vs. 553.3 g; P&lt;0.05) and14% (813.3 vs. 703.3 g; P&gt;0.05) higher fleece weight than that of GI and GII, respectively. Additionally, body weight traits, growth rates, and fiber characteristics were significantly (P&lt;0.05) affected by sex of birth. In conclusion, supplementation with an increased level of feeding concentrate pre-and post-partum of Maraz goats showed a significant (P&lt;0.05) positive effect on productive performance of their kids in comparison to the traditional farmer’s practice.

Wool production and quality traits of pure- and crossbred Merino-type sheep

Very little information is available on the quality of wool produced by terminal crosses out of wool producing dam lines. This study was therefore undertaken to elucidate the wool quality traits of four crossbred lines relative to Merinos and Dohne Merinos, which served as dam lines. Each dam line was mated to rams of their own breed as well as to Dormer or Ile de France rams to create four crossbred lines, namely, Dohne x Dormer, Dohne x Ile de France, Merino x Dormer, and Merino x Ile de France, in addition to the purebred Dohne Merino and Merino lines. Four rams and four ewes from each of these lines were reared up to one year of age under optimal growth conditions and shorn at the end of that time. Fleeces were weighed and samples collected for analysis. Neither sex nor genotype influenced clean fleece weight or clean yield percentage, but fibre diameter differed between genotypes. Purebred Merino had the finest wool (18.26 μm) and the Merino x Dormer cross the coarsest (26.01 μm). However, all lines still produced wool that could be used in manufacturing clothing, while fleeces showed good uniformity. The two purebred lines had the highest comfort factor (> 98%). The crossbred lines produced a similar quantity of wool as the purebreds, although of poorer quality. All genotypes except Merino x Dormer appear to produce wool that could be processed into garments, although the crossbred wool would only be suitable for outerwear.

Características productivas y tecnológicas de la fibra de alpacas Suri del Centro Experimental Chuquibambilla, Puno

This study seeks to determine the productive and technological characteristics of Suri alpaca fiber at the Chuquibambilla Experimental Center. Samples were taken from 110 alpacas during the 2022 shearing campaign, analyzed in the laboratory of INIA’s Quimsachata Experimental Station. The results showed a dirty fleece weight of 2118.64 ± 387.82 g, similar until four years and with a significant decrease from five years (P ≤ 0.05). The average wick length was 88.00 ± 16.13 mm, also similar up to four years. The mean fiber diameter (DMF) was 20.61 ± 0.33 μm, increasing with age (P ≤ 0.05), and the standard deviation of the DMF (DSDMF) was 4.74 ± 0.08 μm, with an age-related increase (P ≤ 0.05). The coefficient of variation of the DMF was 23.06%, with no significant differences between ages (P &gt; 0.05). The comfort factor (HR) was 94.27%, decreasing with age (P ≤ 0.05). Fineness at yarn (FH) averaged 20.46 ± 0.37 μm, increasing with age (P ≤ 0.05), and the curvature index was 15.24 ± 0.37 °/mm, with a significant decrease (P ≤ 0.05). It is concluded that age influences the technological characteristics of the fiber, with positive and negative correlations of high magnitude between the variables analyzed.

Comparison of the Fleece Production of two Extensive French Sheep Genotypes

Sheep fleece became problematic Europe-wide for many reasons, including its very low price. From an animal welfare standpoint, the thick fleece may cause discomfort for the sheep as it can be a welcoming environment for parasites and may cause heat stress during hot summer days; therefore, annual shearing is necessary for most sheep genotypes. Physiologically, growing fleece and maintaining normal body temperature to decrease heat stress distract resources from producing valuable products such as meat. Thus, we aimed to compare the fleece production of two meat-type sheep genotypes from South-France, Berrichon du Cher (Berrichon) and Blanc du Massif Central (BMC), which have relatively little fleece production but thrive in the local Hungarian weather. Furthermore, we fill the gap by providing data on the fleece production of meat-type sheep in Hungary. A total of 180 sheep ewes were included in the data collection (N=99 Berrichon and N=81 BMC). Data was collected at the annual shearing by a digital scale measuring the weight of fleece originating from the back and shoulders. Student’s t test determined the differences in fleece weight between genotypes. Significance was set at P&lt;0.05. The average fleece production of BMC ewes was 1.66 kg, which was significantly (P=0.0001) less than that of Berrichon ewes (2.14 kg). Based on the results, further study is needed to study the performance of BMC ewes with little fleece and their lambs’ in order to improve performance indices and increase profit.

Wool shedding and lamb fleece weights: first-cross and backcross Wiltshire–Romney sheep scored at lamb, hogget and two-tooth ages

ABSTRACT With decreasing wool values, interest is increasing regarding shedding sheep. To investigate this, two long-term studies introducing Wiltshire genes into Romney flocks were initiated. Data from these two studies provide phenotypic relationships between a range of shedding scores at different ages. The data included shedding scores (on a 0–5 scale) repeated on lambs (∼5 months), hoggets (∼14–18 months) and two-tooths (∼27 months), and lamb fleece weights. Positive relationships between shedding scores on the same animals were observed. Lamb fleece weight was negatively correlated with all shedding scores. Lamb shedding score in February had a correlation of 0.54 (P < 0.001) with the February score as a hogget at Riverside farm. Scoring wool shedding is a laborious activity requiring individual animals to be scored in the shearing position. Therefore, lamb fleece weight was investigated for its relationship with shedding scores, as a potentially easier alternative. Lamb fleece weight had a greater correlation with February hogget shedding score than with the lamb shedding score (−0.76 vs −0.52, P < 0.001). This study indicated that February scores are an accurate predictor of future shedding phenotypes, and when used in conjunction with fleece weight, are a good predictor of phenotypes expressed at later ages.

Including genomic information in the genetic evaluation of production and reproduction traits in South African Merino sheep.

Genomic selection (GS) has become common in sheep breeding programmes in Australia, New Zealand, France and Ireland but requires validation in South Africa (SA). This study aimed to compare the predictive ability, bias and dispersion of pedigree BLUP (ABLUP) and single-step genomic BLUP (ssGBLUP) for production and reproduction traits in South African Merinos. Animals in this study originated from five research and five commercial Merino flocks and included between 54,072 and 79,100 production records for weaning weight (WW), yearling weight (YW), fibre diameter (FD), clean fleece weight (CFW) and staple length (SL). For reproduction traits, the dataset included 58,744 repeated records from 17,268 ewes for the number of lambs born (NLB), number of lambs weaned (NLW) and the total weight weaned (TWW). The single-step relationship matrix, H, was calculated using PreGS90 software combining 2811 animals with medium density (~50 K) genotypes and the pedigree of 88,600 animals. Assessment was based on single-trait analysis using ASREML V4.2 software. The accuracy of prediction was evaluated according to the 'LR-method' by a cross-validation design. Validation candidates were assigned according to Scenario I: born after a certain time point; and Scenario II: born in a particular flock. In Scenario I, the genotyping rate for the reference population between 2006 and the 2013 cut-off point approached 7% of animals with phenotypes and 20% of their sires. For reproduction traits, about 20% of ewes born between 2006 and 2011 cut-off were genotyped, along with 15% of their sires. Genotyping rates in the validation set of Scenario I were 3.7% (production) and 11.4% (reproduction) for candidates and 35% of their sires. Sires were allowed to have progeny in both the reference and validation set. In Scenario I, ssGBLUP increased the accuracy of prediction for all traits except NLB, ranging between +8% (0.62-0.67) for FD and +44% (0.36-0.52) for WW. This showed a promising gain in accuracy despite a modestly sized reference population. In the 'across flock validation' (Scenario II), overall accuracy was lower, but with greater differences between ABLUP and ssGBLUP ranging between +17% (0.12-0.14) for TWW and +117% (0.18-0.39) for WW. There was little indication of severe bias, but some traits were prone to over dispersion and the use of genomic information did not improve this. These results were the first to validate the benefit of genomic information in South African Merinos. However, because production traits are moderately heritable and easy to measure at an early age, future research should be aimed at best exploiting GS methods towards genetic prediction of sex-limited and/or lowly heritable traits such as NLW. GS methods should be combined with dedicated efforts to increase genetic links between sectors and improved phenotyping by commercial flocks.

Genetic and environmental parameters for early growth and yearling traits of the Elsenburg South African Mutton Merino resource flock

The Elsenburg South African Mutton Merino (SAMM) resource flock has been maintained at the Elsenburg Research Farm in the Western Cape, South Africa since 1955. Early growth and lamb survival data (record numbers from 9512 for weaning weight or WW to 13101 for lamb survival LS) over the 66-year period from 1955 to 2020 and yearling weight and wool data (record numbers from 1351 the coefficient of variation of fibre diameter or CVFD to 3505 for clean yield or CY) over a 38-year period from 1983 to 2020 were used to estimate genetic and environmental parameters for the flock. The ASREML package was used to estimate fixed effects and genetic parameters. Birth year, sex, birth type and age of dam significantly (P < 0.001) influenced the weight traits and LS. The interaction between birth year and sex was evident in most early growth traits. Direct single-trait heritability estimates amounted to 0.11 ± 0.02 for birth weight (BW), 0.04 ± 0.01 for WW, 0.03 ± 0.01 for LS, 0.28 ± 0.04 for yearling weight (YW), 0.62 ± 0.04 for CY, 0.36 ± 0.04 for clean fleece weight (CFW), 0.33 ± 0.05 for staple length (SL), 0.56 ± 0.06 for CVFD, and 0.65 ± 0.04 for fibre diameter (FD). Maternal heritability estimates were 0.17 ± 0.02 for BW, and 0.06 ± 0.01 for WW. Maternal permanent environmental effects amounted to 0.08 ± 0.02 for BW, 0.04 ± 0.01 for WW, 0.04 ± 0.01, 0.07 ± 0.02 for YW and 0.05 ± 0.02 for CFW. Litter effects were 0.22 ± 0.01 for BW, 0.18 ± 0.02 for WW and 0.14 ± 0.01 for LS. Multi-trait heritability estimates compared well with the single-trait estimates. Genetic correlations for the weight traits in the three-trait analyses ranged from −0.23 ± 0.12 for BW and YW to 0.81 ± 0.09 for WW and YW. Genetic, environmental, and phenotypic correlations amongst yearling weight and wool traits in the six-trait analyses were low to moderate and mostly within the ranges from previous literature for wool breeds. It should be feasible to select for a balanced breeding objective based on economic considerations in the flock.

Live Weight, Fleece Yield and Quality after Shearing in Hamdani and Karakaş Sheep

This study was carried out to determine some wool yield characteristics and post-shearing live weight of 35 head Hamdani and 40 head Karakaş sheep reared in fully extensive conditions in Central Budakli village of Hakkari province.In the study, the results for length (Hauter), length (Barbie), elasticity, fineness, strength, clean fleece percentage, greasy fleece weight and post-shearing live weight were found to be; 42.38 mm-40.51 mm-, 58.25 mm-54.64 mm, 32.34%-32.31%, 36.64 μ-37.62 μ, 36.15 cN tex -34.80 cN tex, 63.88%-65.94%, 2.12 kg-1.84 kg and 60.33 kg-48.55 kg respectively in Hamdani and Karakaş ewes.In Hamdani sheep, the correlation between elasticity and strength (0.499) and between greasy fleece weight and post-shearing live weight (0.599) was very significant (p

Combining host and rumen metagenome profiling for selection in sheep: prediction of methane, feed efficiency, production, and health traits

BackgroundRumen microbes break down complex dietary carbohydrates into energy sources for the host and are increasingly shown to be a key aspect of animal performance. Host genotypes can be combined with microbial DNA sequencing to predict performance traits or traits related to environmental impact, such as enteric methane emissions. Metagenome profiles were generated from 3139 rumen samples, collected from 1200 dual purpose ewes, using restriction enzyme-reduced representation sequencing (RE-RRS). Phenotypes were available for methane (CH4) and carbon dioxide (CO2) emissions, the ratio of CH4 to CH4 plus CO2 (CH4Ratio), feed efficiency (residual feed intake: RFI), liveweight at the time of methane collection (LW), liveweight at 8 months (LW8), fleece weight at 12 months (FW12) and parasite resistance measured by faecal egg count (FEC1). We estimated the proportion of phenotypic variance explained by host genetics and the rumen microbiome, as well as prediction accuracies for each of these traits.ResultsIncorporating metagenome profiles increased the variance explained and prediction accuracy compared to fitting only genomics for all traits except for CO2 emissions when animals were on a grass diet. Combining the metagenome profile with host genotype from lambs explained more than 70% of the variation in methane emissions and residual feed intake. Predictions were generally more accurate when incorporating metagenome profiles compared to genetics alone, even when considering profiles collected at different ages (lamb vs adult), or on different feeds (grass vs lucerne pellet). A reference-free approach to metagenome profiling performed better than metagenome profiles that were restricted to capturing genera from a reference database. We hypothesise that our reference-free approach is likely to outperform other reference-based approaches such as 16S rRNA gene sequencing for use in prediction of individual animal performance.ConclusionsThis paper shows the potential of using RE-RRS as a low-cost, high-throughput approach for generating metagenome profiles on thousands of animals for improved prediction of economically and environmentally important traits. A reference-free approach using a microbial relationship matrix from log10 proportions of each tag normalized within cohort (i.e., the group of animals sampled at the same time) is recommended for future predictions using RE-RRS metagenome profiles.

Longitudinal assessment of the impact of aging on wastage, productivity and welfare of ewes

Retention of aging ewes is a strategy producers may use to maintain or increase flock size. Older ewes can have a higher risk of mortality and health issues, but these may be minimised with early intervention and culling. This retrospective study examined the incidence and causes of mortality and culling in a flock of Merino ewes as they aged from 4.5 to 5.5 until 9.5 to 10.5 years. The annual rate of ewe mortality ranged from 6.2% to 9.9%, with lambing complications being the major source of reported loss. Annual culling rates ranged from 1.6% to 42.8%, the larger rates reflecting opportunistic replacement with younger ewes rather than essential culling to maintain welfare and productivity. The major reasons for culling were low condition score, worn or missing teeth or faulty udders. The incidence of other faults was low. Only 18.3% of ewes remained when aged 9.5-10.5 years and these were fertile (89% pregnant) with a high proportion of multiple fetuses (52%) in their final year, although fleece weight had declined. Younger ewes born in 2004/2005 tended to have lower annual mortality rates than the aged ewes, but 8%-12% were still culled annually. It is concluded that an annual inspection pre-joining of all ewes and preventative culling for health issues is necessary to minimise any increase in mortality and risk to ewe welfare from retaining aging ewes. More frequent inspection will be required as potential health issues develop during the year, as these may not be evident pre-joining.