Phenotypic Responses to Selection for Ultrafine Wool in Uruguayan Yearling Lambs

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

doi:10.3390/agriculture11020179

Cited by 4 publications

(14 citation statements)

References 33 publications

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“…Each year, ewes were managed as a single flock under the same health and nutritional conditions, as recommended for commercial flocks [27,28]. Ewes grazed on native pastures (6-15% of crude protein and 7.5-9.2 MJ/kg metabolizable energy) [29], with access to improved pastures or supplements as described by Ramos et al [24].…”

Section: Animals Nutrition and Managementmentioning

confidence: 99%

“…Each year ewes were inseminated with either imported frozen semen or fresh semen from nucleus-born rams [24]. Estrus was synchronized using intravaginal sponges impregnated with progesterone (Intervet ® , Montevideo, Uruguay, SFGA 40 mg) for 12-14 days followed by a single intramuscular injection of equine chorionic gonadotropin (Folligon ® , Intervet, Montevideo, Uruguay, 200-300 UI/a) at the time of sponge removal.…”

Section: Animals Nutrition and Managementmentioning

confidence: 99%

“…Additionally, approximately one month prior to lambing, all pregnant ewes were group fed 400 g of grain/ewe/day (sorghum or commercial rations). Ewe and newborn lamb management at lambing time is described in Ramos et al [24].…”

Section: Animals Nutrition and Managementmentioning

confidence: 99%

“…Internal parasite control was done by oral drench with an effective anthelmintic prior to mating (March to April), lambing (July to August), at lamb marking (September to November) and weaning (December to February). In addition to these internal parasite control treatments, fecal egg counts were monitored as described by Ramos et al [24].…”

Section: Animals Nutrition and Managementmentioning

confidence: 99%

“…Between 1999 and 2020, two combined research projects entitled the Fine Merino Project (FMP) and the Regional Consortium for Innovation in Ultrafine Wool (CRILU) were developed in Uruguay, as described by Ramos et al [24]. Briefly, the FMP (1999-2010) focused on FD reduction (19 µm or finer), whereas during the CRILU period (2011-2020), the selection objective was to reduce FD (15.5 µm or finer) and to increase both CFW and live weight (LW).…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2021

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This study reports the phenotypic trends for wool, growth, and reproductive traits in mixed-age ewes after twenty years of genetic selection. Data were obtained from the Merino nucleus flock in Uruguay between 1999 and 2020. Overall, the aim of this selection flock was to reduce the fiber diameter (FD) and increase both the clean fleece weight (CFW) and live weight (LW). Data on ewe wool traits, LW, body condition score (BCS), the total number of lambs weaned (TLW), and the total LW of lambs weaned (TWW) across all lambing opportunities (1–8 mating seasons) were analyzed. Between 1292 and 2063 ewes were measured, depending on the trait considered. Ewe FD decreased by approximately 3 µm (19–16 µm), whereas greasy fleece weight (GFW) increased by 0.2 kg. This improvement in wool traits was accompanied by increases in LW at mating (3 kg), decreases in BCS at mating (approximately by 1 unit), and a small positive change in TWW across years. This study demonstrated that increasing farmer income by selecting for finer wool, heavier fleeces, and heavier animals can be obtained without compromising ewe lifetime reproduction.

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Section: Animals Nutrition and Managementmentioning

confidence: 99%

Section: Animals Nutrition and Managementmentioning

confidence: 99%

Section: Animals Nutrition and Managementmentioning

confidence: 99%

Section: Animals Nutrition and Managementmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

et al. 2021

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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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Relationship between skin structure and wool traits for Ultrafine and Dohne Merino sheep of Uruguay

Adriana¹,

Daniel²,

Ramos³

et al. 2021

World J. Adv. Res. Rev.

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The demand in the world market for high quality fine and superfine wool is increasing, responding to greater wool textile industry demands and price incentives. There are few research studies focused on hair follicle population in fine and superfine Merino sheep in Uruguay. This study evaluates the association between wool follicle population and the most relevant economical wool traits. This work was carried out on Ultrafine Australian Merino (UAM) and Dohne Merino (DM) animals (lambs and rams). Phenotypic correlations between the secondary/primary follicles (S/P) and other wool traits (fiber diameter, staple length, clean fleece weight, scoured yield, coefficient of variation of fiber diameter and comfort factor parameter, were performed using histological skin cuts. Two skin samples were extracted from each lamb at two and nine months of age. These were processed at the skin histology laboratory to obtain a histological preparation for further biopsy, being able to differentiate the structures obtained to be evaluated. The results showed in the UAM group, S/P ratio in nine-month-old lambs was greater than two-month-old lambs (31.08 vs 23.12 P< 0.05). For DM group, there were no differences in the S/P ratio between age groups. Phenotypic correlations for wool characteristics obtained were of low to medium or null magnitude in both genotypes.

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Phenotypic Responses to Selection for Ultrafine Wool in Uruguayan Yearling Lambs

Cited by 4 publications

References 33 publications

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

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

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

Relationship between skin structure and wool traits for Ultrafine and Dohne Merino sheep of Uruguay

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