Genetic parameters for strongyle and Nematodirus faecal egg counts in lambs and their relationships with performance traits

Wolf, B. T.; Howells, KM; Nakielny, C.; Haresign, W.; Lewis, R. M.; Davies, Owen; Davies, M.

doi:10.1016/j.livsci.2007.03.011

Cited by 12 publications

(7 citation statements)

References 34 publications

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“…However, positive and moderate to strong genetic correlations between Nematodirus and Strongyles FEC ranging from 0.49 to 0.93 have been reported , Morris et al, 2004, Wolf et al, 2008. This implies, therefore, some common genetic mechanisms responsible for resistance to Strongyles and Nematodirus; hence, it may be hypothesised that some SNPs or QTL underlying genetic variation in Nematodirus and Strongyles FEC may be in common.…”

Section: Discussionmentioning

confidence: 99%

Genome-wide association and regional heritability mapping to identify loci underlying variation in nematode resistance and body weight in Scottish Blackface lambs

et al. 2013

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The genetic architecture underlying nematode resistance and body weight in Blackface lambs was evaluated comparing genome-wide association (GWA) and regional heritability mapping (RHM) approaches. The traits analysed were faecal egg count (FEC) and immunoglobulin A activity against third-stage larvae from Teladorsagia circumcincta, as indicators of nematode resistance, and body weight in a population of 752 Scottish Blackface lambs, genotyped with the 50k single-nucleotide polymorphism (SNP) chip. FEC for both Nematodirus and Strongyles nematodes (excluding Nematodirus), as well as body weight were collected at approximately 16, 20 and 24 weeks of age. In addition, a weighted average animal effect was estimated for both FEC and body weight traits. After quality control, 44 388 SNPs were available for the GWA analysis and 42 841 for the RHM, which utilises only mapped SNPs. The same fixed effects were used in both analyses: sex, year, management group, litter size and age of dam, with day of birth as covariate. Some genomic regions of interest for both nematode resistance and body weight traits were identified, using both GWA and RHM approaches. For both methods, strong evidence for association was found on chromosome 14 for Nematodirus average animal effect, chromosome 6 for Strongyles FEC at 16 weeks and chromosome 6 for body weight at 16 weeks. Across the entire data set, RHM identified more regions reaching the suggestive level than GWA, suggesting that RHM is capable of capturing some of the variation not detected by GWA analyses.

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Section: Discussionmentioning

confidence: 99%

Genome-wide association and regional heritability mapping to identify loci underlying variation in nematode resistance and body weight in Scottish Blackface lambs

et al. 2013

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“…(Bishop et al, 2004;Davies et al, 2006;Salle G. and Bishop SC, 2007 unpublished results), although both types of FEC are heritable. Reported genetic correlations between Nematodirus and Strongyles FEC are invariably positive and moderate to strong, ranging from 0.49 to 0.93, across a range of environments and breeds (Bishop et al, 2004;Morris et al, 2004;Wolf et al, 2008). These estimated genetic correlations imply some common genetic mechanisms responsible for resistance to Strongyles and Nematodirus; hence, it may be hypothesised that some of the QTL underlying genetic variation in Nematodirus and Strongyles FEC may be in common.…”

Section: Discussionmentioning

confidence: 99%

Confirmation of two quantitative trait loci regions for nematode resistance in commercial British terminal sire breeds

Matika

Pong‐Wong

Woolliams

et al. 2011

Animal

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Sheep internal parasites (nematodes) remain a major health challenge and are costly for pasture-based production systems. Most current breeding programmes for nematode resistance are based on indicator traits such as faecal egg counts (FEC), which are costly and laborious to collect. Hence, genetic markers for resistance would be advantageous. However, although some quantitative trait loci (QTL) have been identified, these QTL are often not consistent across breeds and few breeding strategies for nematode resistance in sheep are currently using molecular information. In this study, QTL for nematode resistance on ovine chromosomes (OAR) 3 and 14, previously identified in the Blackface breed, were explored using commercial Suffolk (n 5 336) and Texel lambs (n 5 879) sampled from terminal sire breeder flocks in the United Kingdom. FEC were used as the indicator trait for nematode resistance, and these were counted separately for Nematodirus and Strongyles genera. Microsatellite markers were used to map the QTL and the data were analysed using interval mapping regression techniques and variance component analysis. QTL for Nematodirus and Strongyles FEC were found to be segregating on OAR3 at 5% chromosome region-wide significance threshold in both Suffolk and Texel sheep, and Nematodirus FEC QTL were segregating on OAR14 in both breeds. In addition, QTL for growth traits were also found to be segregating at 5% chromosome region-wide on OAR3 and OAR14. The confirmation that FEC QTL segregate in the same position in three widely used breeds widens their potential applicability to purebred Blackface, Suffolk and Texel sheep, with benefits likely to be observed in their commercial crossbred progeny.

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“…A possible effect of maternal undernutrition on offspring health was assessed through FEC determination in twin lambs. Twin lambs were expected to show greater effects of maternal undernutrition on subsequent parasitism than single lambs because twin lambs are usually more susceptible (Wolf et al, 2008). The pasture infectivity likely differed between the 2 yr, as FEC for other strongyle spp.…”

Section: Discussionmentioning

confidence: 99%

“…Nonparametric data (birth presentation, lamb survival) were analyzed using contingency tables and χ 2 test. Because twin lambs were selected for FEC, because of expected greater susceptibility to infection (Wolf et al, 2008), and because all pens could not be represented in the data set, FEC data were analyzed as follows. Fecal egg counts were square-root transformed before analysis.…”

Section: Statistical Analysesmentioning

confidence: 99%

Differential effects of maternal undernutrition between days 1 and 90 of pregnancy on ewe and lamb performance and lamb parasitism in hill or lowland breeds1

Rooke¹,

Houdijk²,

McIlvaney³

et al. 2010

Journal of Animal Science

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This study examined the hypothesis that responses of Scottish Blackface (BF, a hill breed) and Suffolk (SUF, a lowland breed) ewes to undernutrition between d 1 and 90 of pregnancy would differ. Over 2 consecutive breeding seasons, ewes (4 pens/treatment; 15 to 20 ewes/pen) were artificially inseminated and from d 1 to 90 after AI allocated to 0.75 (restricted; RES) or 1.0 (control; CON) energy requirements for ewe maintenance and fetal growth. From d 90 to term, all ewes were allocated feed to meet requirements for stage of pregnancy and expected litter size. On d 90, RES ewes had lighter BW (P = 0.001) and smaller BCS (P = 0.019) than CON ewes. Plasma NEFA concentrations were greater in RES than CON ewes (P = 0.048) at d 60 of pregnancy. Pregnancy length was longer for RES than CON ewes (P = 0.003). Lambs from SUF-RES ewes had lighter birth weights than SUF-CON lambs, but BF-RES lamb birth weights were not different from BF-CON lambs (interaction, P = 0.066). However, maternal undernutrition did not affect BW at weaning (P > 0.45). Between birth and 3 d of age, BF lambs maintained greater body temperatures (P < 0.001) and plasma concentrations of triiodothyronine (T3, P < 0.001) and thyroxine (P < 0.001) than SUF lambs. Lambs from RES ewes had greater concentrations of T3 (P = 0.026) than CON lambs, whereas these differences were greater between BF-RES and BF-CON lambs than between SUF-RES and SUF-CON lambs (interaction, P = 0.028). Maternal undernutrition did not affect lamb rectal temperature (P > 0.27). In yr 1 only, fewer lambs (P = 0.022) were reared to weaning by RES than CON ewes. Similarly, in yr 1 only, other strongyle fecal egg counts at weaning were greater in SUF-RES lambs than SUF-CON, BF-CON, or BF-RES lambs (interaction, P = 0.099). This experiment showed that lambs of a breed selected for lean tissue growth and normally maintained in a lowland environment were more affected by maternal undernutrition between d 1 and 90 of pregnancy than lambs of a hill breed managed in a more adverse environment.

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Genetic parameters for strongyle and Nematodirus faecal egg counts in lambs and their relationships with performance traits

Cited by 12 publications

References 34 publications

Genome-wide association and regional heritability mapping to identify loci underlying variation in nematode resistance and body weight in Scottish Blackface lambs

Genome-wide association and regional heritability mapping to identify loci underlying variation in nematode resistance and body weight in Scottish Blackface lambs

Confirmation of two quantitative trait loci regions for nematode resistance in commercial British terminal sire breeds

Differential effects of maternal undernutrition between days 1 and 90 of pregnancy on ewe and lamb performance and lamb parasitism in hill or lowland breeds1

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