Productivity and Reproductive Performance of Mixed-Age Ewes across 20 Years of Selection for Ultrafine Wool in Uruguay

Ramos, Zully; Blair, Hugh T.; Barbieri, I. De; Ciappesoni, Gabriel; Montossi, F.; Kenyon, P. R.

doi:10.3390/agriculture11080712

Cited by 3 publications

(2 citation statements)

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“…The data were derived from a Uruguayan Merino nucleus flock involved in a genetic program, as described by Ramos et al [21,22]. The selection objectives, nutritional conditions and management of this flock were previously reported by Ramos et al [22]. Phenotypic records of these six traits were obtained from approximately 2000 mixed-age ewes born between 1999 and 2018.…”

Section: Phenotypic and Pedigree Datamentioning

confidence: 99%

“…The traits evaluated were the adult fiber diameter and clean fleece weight at late-pregnancy shearing (A_FD and A_CFW, respectively); live weight and body condition score at mating (LWM and BCSM, respectively); pregnancy rate (PR: pregnant or non-pregnant); and lambing potential (LP: the number of ultrasoundscanned fetuses per ewe combined: 0, 1 or ≥2). Details of the trait measurements were described by Ramos et al [21,22]. The complete pedigree included 7168 animals.…”

Section: Phenotypic and Pedigree Datamentioning

confidence: 99%

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Genomic Regions Associated with Wool, Growth and Reproduction Traits in Uruguayan Merino Sheep

Ramos

Garrick

Blair

et al. 2023

Genes

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The aim of this study was to identify genomic regions and genes associated with the fiber diameter (FD), clean fleece weight (CFW), live weight (LW), body condition score (BCS), pregnancy rate (PR) and lambing potential (LP) of Uruguayan Merino sheep. Phenotypic records of approximately 2000 mixed-age ewes were obtained from a Merino nucleus flock. Genome-wide association studies were performed utilizing single-step Bayesian analysis. For wool traits, a total of 35 genomic windows surpassed the significance threshold (PVE ≥ 0.25%). The proportion of the total additive genetic variance explained by those windows was 4.85 and 9.06% for FD and CFW, respectively. There were 42 windows significantly associated with LWM, which collectively explained 43.2% of the additive genetic variance. For BCS, 22 relevant windows accounted for more than 40% of the additive genetic variance, whereas for the reproduction traits, 53 genomic windows (24 and 29 for PR and LP, respectively) reached the suggestive threshold of 0.25% of the PVE. Within the top 10 windows for each trait, we identified several genes showing potential associations with the wool (e.g., IGF-1, TGFB2R, PRKCA), live weight (e.g., CAST, LAP3, MED28, HERC6), body condition score (e.g., CDH10, TMC2, SIRPA, CPXM1) or reproduction traits (e.g., ADCY1, LEPR, GHR, LPAR2) of the mixed-age ewes.

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Section: Phenotypic and Pedigree Datamentioning

confidence: 99%

Section: Phenotypic and Pedigree Datamentioning

confidence: 99%

Genomic Regions Associated with Wool, Growth and Reproduction Traits in Uruguayan Merino Sheep

Ramos

Garrick

Blair

et al. 2023

Genes

Self Cite

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Genetic and phenotypic relationships between ewe reproductive performance and wool and growth traits in Uruguayan Ultrafine Merino sheep

Ramos

Garrick

Blair

et al. 2023

Journal of Animal Science

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This study reports genetic parameters for yearling and adult wool and growth traits, and ewe reproductive performance. Data were sourced from an Uruguayan Merino flock involved in a long-term selection program focused on reduced fibre diameter (FD), and increased clean fleece weight (CFW) and live weight (LW). Pedigree and performance data from approximately 5,700 mixed-sex yearling lambs and 2,000 mixed-age ewes born between 1999 and 2019 were analysed. The number of records ranged from 1,267 to 5,738 for yearling traits, and from 1,931 to 7,079 for ewe productive and reproductive performance. Data on yearling and adult wool traits, LW and body condition score (BCS), yearling eye muscle area (Y_EMA), and fat thickness (Y_FAT), and several reproduction traits were analysed. The genetic relationships between FD and reproduction traits were not different from zero. Moderate unfavourable genetic correlations were found between adult CFW and ewe lifetime reproduction traits (-0.34 ± 0.08 and -0.33 ± 0.09 for total number of lambs weaned and total lamb live weight at weaning, respectively). There were moderate to strong positive genetic correlations between yearling LW and all reproduction traits other than ewe rearing ability (-0.08 ± 0.11) and pregnancy rate (0.18 ± 0.08). The genetic correlations between Y_EMA and reproduction traits were positive and ranged from 0.15 to 0.49. Moderate unfavourable genetic correlations were observed between yearling FD and Y_FAT and between adult FD and BCS at mating (0.31 ± 0.12 and 0.23 ± 0.07, respectively). The genetic correlations between adult fleece weight and ewe BCS at different stages of the cycle were negative, but generally not different from zero. This study shows that selection for reduced FD is unlikely to have any effect on reproduction traits. Selection for increased yearling LW and Y_EMA will improve ewe reproductive performance. On the other hand, selection for increased adult CFW will reduce ewe reproductive performance, whereas selection for reduced FD will negatively impact on body fat levels. Although unfavourable genetic relationships between wool traits and both FAT and ewe reproductive performance existed, simultaneous improvements in the traits would occur using appropriately designed indexes.

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Protective properties of the fleece of Taurian ewesof the Askanian fine fleece breed depending on the breeding differentiation rank

Tyrunskiy,

Bogdanova,

Lyutskanov

2023

Animal Science and Food Technology

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The study of factors affecting the humidity and contamination of the outer and inner zones of the staple, which further affects the yield of pure wool and its technological properties, is one of the current problems of fine-fleeced sheep breeding. Purpose of the study – evaluate the protective properties of wool fleece depending on the rank of breeding differentiation of sheep. The determination of ranks is based on the regularities of the normal distribution of animals in the population and herd reproduction indicators. 10 ranks were used. The paper presents the results of a laboratory study of the content of mineral impurities and the degree of contamination of the staple. Sheep were divided into 10 ranks of breeding differentiation. The regularities of the normal distribution of animals in the population are considered. The obtained data indicate that the variety of sheep in terms of the content of mineral impurities in wool is very large. The coefficient of variation is 35% with a variation in the ranks of breeding differentiation from 13.7 to 38.4%. With an increase in the group of the total value of sheep for breeding purposes, the value of the coefficient of variation decreases (rs=-0.871±0.245). With an increase in the ranks of breeding differentiation, the average absolute indicators of contamination of the outer zone of the staple tend to increase (rs = +0.257 ± 0.483), and the relative values decrease (rs =-0.600 ± 0.400). The average absolute contamination rate of the inner zone of the staple is 3.02 cm with a range of ranks from 2.83 to 3.29 cm. According to the relative degree of contamination, these indicators are 32.5% and from 31.0 to 35.2%, respectively. With an increase in the breeding differentiation rank of sheep, the absolute indicators of contamination of the length of the inner zone of the staple increase (rs = +0.600 ± 0.400), and relative values tend to decrease (rs =-0.486 ± 0.437). The individual variety of ewes in terms of the degree of contamination of the inner zone of the staple is quite high. The coefficients of variation for absolute and relative indicators of this feature are 28.5 and 30.4%, respectively. The value of the coefficients of variation decreases slightly with an increase in the ranks of breeding purposes of animals. The rank correlation is -0.371 ± 0.464 in absolute terms and -0.543 ± 0.420 in relative terms. Breeding differentials of the leading groups of ewes are low. Using this rank technique allows controlling the system of sheep valuation, supplementing it with the value of breeding differentials at the final stages of analysis and selection; in production conditions allows forming technological groups of sheep to produce outstanding ram breeders

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Productivity and Reproductive Performance of Mixed-Age Ewes across 20 Years of Selection for Ultrafine Wool in Uruguay

Cited by 3 publications

References 38 publications

Genomic Regions Associated with Wool, Growth and Reproduction Traits in Uruguayan Merino Sheep

Genomic Regions Associated with Wool, Growth and Reproduction Traits in Uruguayan Merino Sheep

Genetic and phenotypic relationships between ewe reproductive performance and wool and growth traits in Uruguayan Ultrafine Merino sheep

Protective properties of the fleece of Taurian ewesof the Askanian fine fleece breed depending on the breeding differentiation rank

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