Genetic parameters for nematode resistance in periparturient ewes and post-weaning lambs in Uruguayan Merino sheep

Goldberg, Virginia; Ciappesoni, Gabriel; Aguilar, Ignácio

doi:10.1016/j.livsci.2012.05.003

Cited by 26 publications

(26 citation statements)

References 15 publications

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“…Alternatively, if G ij r = 0.7, then observed correlations of 0.09 and 0.05 correspond to heritability estimates of 0.26 and 0.14, respectively. These hypothetical values for E i h , L j h , and G ij r are reasonably consistent with the literature (Safari et al, 2005;Goldberg et al, 2012;Brown and Fogarty, 2016), given the limited number of observations available in this study.…”

Section: Discussionsupporting

confidence: 91%

“…Results of Woolaston (1992) support the concept that similar mechanisms control parasite resistance in periparturient ewes and growing lambs and that information from both classes of animals can be combined to enhance selection responses in overall parasite resistance in the flock. However, results in Merino ewes in Uruguay indicated that heritabilities of FEC were considerably higher in lambs than in periparturient ewes and that indirect selection based on lamb FEC would be more effective than direct selection based on ewe FEC in limiting the periparturient rise (Goldberg et al, 2012).…”

Section: Discussionmentioning

confidence: 93%

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Factors affecting fecal egg counts in periparturient Katahdin ewes and their lambs

Notter¹,

Burke²,

Miller³

et al. 2017

Journal of Animal Science

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Selection for low fecal egg counts (FEC) can be used to genetically enhance resistance to gastrointestinal nematode parasites in growing lambs, thereby reducing the frequency of use of anthelmintics, facilitating marketing of organic lamb, and reducing the risk of development of anthelmintic resistance by the parasite. Recording of FEC in lambs has, therefore, been incorporated into several national sheep genetic evaluation programs. Ewes in late gestation and early lactation are also vulnerable to parasite infection and commonly experience a periparturient rise in FEC. This study was designed to assess factors associated with the periparturient rise in FEC in Katahdin ewes and associated changes in FEC in their lambs. Data came from 1,487 lambings by 931 Katahdin ewes from 11 farms in the Eastern United States. Fecal egg counts were measured in ewes at approximately 0, 30, and 60 d postpartum and in their lambs at approximately 60, 90, and 120 d of age. Approximately 1,400 lambs were evaluated at each measurement age. Data were analyzed separately for ewes and lambs and also initially analyzed separately for each measurement time. Repeated-measures analyses were then used to evaluate responses across measurement times. In ewes, FEC peaked at approximately 28 d postpartum, and we concluded that informative periparturient FEC could be obtained from 1 wk before until approximately 5 wk after lambing. Yearling ewes had higher FEC than adult ewes ( < 0.01), and ewes that nursed twin or triplet lambs had higher FEC than ewes that nursed single lambs ( < 0.01). In lambs, FEC increased through approximately 120 d of age. Lambs from yearling ewes and lambs nursed in larger litters were, like their dams, at greater risk of parasitism ( < 0.05). Ewes and lambs in these groups would benefit from enhanced monitoring of parasite loads at lambing and in early lactation. Correlations () between FEC in lambs at 90 d of age and FEC in ewes at 0, 30, and 60 d postpartum of 0.05 to 0.09 ( ≤ 0.05) support the presence of a genetic relationship between these 2 indicators of parasite resistance.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 93%

Factors affecting fecal egg counts in periparturient Katahdin ewes and their lambs

Notter¹,

Burke²,

Miller³

et al. 2017

Journal of Animal Science

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“…; Goldberg et al . ), and FEC was determined on each sample. The SBF population comprised growing lambs facing natural (mixed species) challenge at pasture; the MBR comprised growing lambs facing deliberate Haemonchus contortus challenge; and the SAR population comprised lactating ewes facing natural (mixed species) challenge at pasture.…”

Section: Methodsmentioning

confidence: 99%

“…Faecal samples were collected from the rectum of the animals at different ages for the different populations, assuming that FEC at different ages is genetically correlated (Bishop et al 1996;Goldberg et al 2012), and FEC was determined on each sample. The SBF population comprised growing lambs facing natural (mixed species) challenge at pasture; the MBR comprised growing lambs facing deliberate Haemonchus contortus challenge; and the SAR population comprised lactating ewes facing natural (mixed species) challenge at pasture.…”

Section: Phenotypic Measurementsmentioning

confidence: 99%

A joint analysis to identify loci underlying variation in nematode resistance in three European sheep populations

Riggio

Pong‐Wong

Sallé

et al. 2014

J Animal Breeding Genetics

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Gastrointestinal nematode infections are one of the main health/economic issues in sheep industries, worldwide. Indicator traits for resistance such as faecal egg count (FEC) are commonly used in genomic studies; however, published results are inconsistent among breeds. Meta (or joint)-analysis is a tool for aggregating information from multiple independent studies. The aim of this study was to identify loci underlying variation in FEC, as an indicator of nematode resistance, in a joint analysis using data from three populations (Scottish Blackface, Sarda × Lacaune and Martinik Black-Belly × Romane), genotyped with the ovine 50k SNP chip. The trait analysed was the average animal effect for Strongyles and Nematodirus FEC data. Analyses were performed with regional heritability mapping (RHM), fitting polygenic effects with either the whole genomic relationship matrix or matrices excluding the chromosome being interrogated. Across-population genomic covariances were set to zero. After quality control, 4123 animals and 38 991 SNPs were available for the analysis. RHM identified genome-wide significant regions on OAR4, 12, 14, 19 and 20, with the latter being the most significant. The OAR20 region is close to the major histocompatibility complex, which has often been proposed as a functional candidate for nematode resistance. This region was significant only in the Sarda × Lacaune population. Several other regions, on OAR1, 3, 4, 5, 7, 12, 19, 20 and 24, were significant at the suggestive level.

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“…Hay dos grandes líneas principales en ese sentido, aunque sean incipientes o estén en etapa experimental inicial. Una vinculada a la selección genética de ovinos resistentes a los parásitos gastrointestinales (Ciappesoni et al, 2009;Goldberg, 2011;Goldberg et al, 2012). La otra pasa por el uso de forrajes bioactivos (aquellos con compuestos secundarios que ejercen algún efecto de control sobre éstos parásitos, como por ejemplo Lotus pedunculatus y L. corniculatus) o por la administración de taninos condensados desde otras fuentes (por ejemplo extracto de Quebracho -Shinopsis spp.-) para el control parasitario (Mederos & Banchero, 2013).…”

Section: D) Falta De Investigación Hacia Un Manejo De Base Agroecológicaunclassified

¿Resistencia o propuesta? Situación y perspectivas de la producción ovina agroecológica en la Región Metropolitana de Uruguay

Ferreira

2018

Desenvolv. Meio Ambiente

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Nos últimos anos, a produção de ovinos mostrou sinais de crescimento na Região Metropolitana (RM) do Uruguai e aparece como possibilidade para os agricultores familiares na Região. Em particular, a produção de ovinos baseada no manejo agroecológico aparece como alternativa para esses agricultores. Este estudo analisa a situação da produção de ovinos na RM, especialmente aquela de base agroecológica, visando identificar e avaliar essa proposta como uma possível alternativa de resistência para agricultores familiares na Região. Para isso, suas principais possibilidades e limitações foram analisadas. Pesquisa documental e bibliográfica foram realizadas para analisar as transformações da realidade agrária e na produção de ovinos na Região nos últimos anos. Entrevistas com técnicos e produtores com ligação e experiência com o tema foram implementadas, assim como um grupo de discussão. Em nosso trabalho fica evidente que o crescimento da produção de ovinos nos últimos quinze anos na RM esteve especialmente baseado nos pequenos agricultores familiares locais, em contraste com o desenvolvimento histórico dessa produção no país. Em relação à produção agroecológica de ovinos, existem experiências incipientes que geram interesse em consumidores e alguns produtores, mas seu espaço é quase nulo na pesquisa e nas políticas públicas, com pouco conhecimento acumulado sobre o assunto. Fomentar a pesquisa, formação e, principalmente, o debate sobre a necessidade de mudanças em modelos tecnológicos no interior das organizações de agricultores familiares aparecem como movimentos necessários para tornar a produção agroecológica de ovinos uma alternativa viável.

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Genetic parameters for nematode resistance in periparturient ewes and post-weaning lambs in Uruguayan Merino sheep

Cited by 26 publications

References 15 publications

Factors affecting fecal egg counts in periparturient Katahdin ewes and their lambs

Factors affecting fecal egg counts in periparturient Katahdin ewes and their lambs

A joint analysis to identify loci underlying variation in nematode resistance in three European sheep populations

¿Resistencia o propuesta? Situación y perspectivas de la producción ovina agroecológica en la Región Metropolitana de Uruguay

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