Resistance to experimental infections  with Haemonchus contortus  in Romanov sheep

Luffau, G.; Khang, J. Wu Tien; Bouix, J.; Nguyen, Thanh N.; Cullen, P.; Ricordeau, G.; Carrat, C.; Eychenne, F.

doi:10.1051/gse:19900205

Cited by 3 publications

(3 citation statements)

References 16 publications

(18 reference statements)

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“…1998). However, this relationship has not been confirmed by other studies ( Luffau et al. 1990; amongst others).…”

Section: Discussioncontrasting

confidence: 59%

Structure of European ovine populations from directional autocorrelations between proteins

Ordás

2004

J Animal Breeding Genetics

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The allele frequencies of haemoglobin, esterase, albumin and transferrin in European ovine populations were analysed by directional autocorrelation. The correlograms of the haemoglobin B and transferrin D show that these alleles have north/northeast-south/southwest and northeast-southwest clines in Europe, respectively. The clines observed may be the result of selection or ovine population expansion since domestication. ZusammenfassungDie Struktur europä ischer Schafpopulationen ermittelt durch direktionale Autokorrelation zwischen Proteinen Die Allelfrequenzen von Hämoglobin, Esterase, Albumin und Transferrin in europäischen Schafpopulationen wurden mit Hilfe von direktionaler Autokorrelation analysiert. Die Korrelogramme von Hämoglobin B und Transferrin D zeigen, dass diese Allele ein Nord/Nordost-Sü d/Sü dwest-bzw. ein Nordost-Sü dwest-Gefälle aufweisen. Die gefundenen Gefälle kö nnten das Ergebnis von Selektion oder von Ausdehnung der Schafpopulationen seit der Domestikation sein.

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“…1998). However, this relationship has not been confirmed by other studies ( Luffau et al. 1990; amongst others).…”

Section: Discussioncontrasting

confidence: 59%

Structure of European ovine populations from directional autocorrelations between proteins

Ordás

2004

J Animal Breeding Genetics

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“…Some of these studies have been summarized in Table 7 . Polymorphisms within the ovine MHC complex were associated with resistance to T. colubriformis ( Douch and Outteridge, 1989 ), T. circumcincta ( Schwaiger et al, 1995 ), and H. contortus ( Luffau et al, 1990 ; Outteridge et al, 1996 ). However, Cooper et al (1989) , Blattman et al (1993) and Hulme et al (1993) did not find evidence of an association between polymorphisms in the ovine MHC locus and resistance or susceptibility to H. contortus .…”

Section: Discussionmentioning

confidence: 99%

Fecal egg counts for gastrointestinal nematodes are associated with a polymorphism in the MHC-DRB1 gene in the Iranian Ghezel sheep breed

et al. 2015

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Genetic variation among sheep breeds in resistance to gastrointestinal nematodes (GIN) has been demonstrated in several production environments. Relationships between the ovine major histocompatibility complex and resistance to GIN have been studied, but few studies have systematically examined this issue in less-developed and semi-arid regions. The aim of the current study was to explore associations between fecal worm egg counts (FEC) for several GIN and polymorphisms in the DRB1 gene. One hundred male lambs were selected at 4–6 months of age from weaned animals in five flocks (n = 20 per flock). Body weights were determined, FAMACHA scores based on color of the ocular mucous membranes were assigned as an indicator of anemia, and blood and fecal samples were collected twice to evaluate FEC and blood packed cell volume (PCV) and for DNA isolation. A repeated-measures analysis of variance was used to test effects of genotype on FEC. The model included fixed effects of flock, genotype, time of measurement (1 or 2), and flock × time and genoype × time interactions, and a random (repeated) effect of lamb. Two genotypes (A1A1 and A1A2) were observed following digestion of Region 1 of Ovar-DRB1 with PstI. Genotypic frequencies were 0.73 for A1A1 and 0.27 for A1A2. FEC differed between Ovar_DRB1 genotypes A1A1 and A1A2 for Marshallagia marshalli, Strongyle, and total nematode FEC. Observed FEC were 30–41% lower for genotype A1A1. Differences among genotypes were consistent across measurement times, with no effect of genotype × measurement time interaction for any parasite class (P ≥ 0.34). A significant association was observed between FAMACHA scores and lamb PCV, and the residual correlation between these two variables was -0.51 (P < 0.001). FAMACHA scores can thus be used to detect differences among lambs in PCV, and polymorphic markers of Ovar-DRB1 have potential value as an indicator of parasite resistance in applied animal breeding programs on sheep farms in this region.

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“…These changes in the pattern of egg excretion were probably due to the fenbendazole treatment. Benitez-Usher et al [5] and Luffau et al [22] have shown that thiabendazole treatment prevents the expression of immunity acquired by previous contact with Haemonchus contortus. Cabaj et al [8] also found changes in the immune system of sheep that had been drenched with fenbendazole.…”

Section: Discussionmentioning

confidence: 99%

A short-term divergent selection for resistance to Teladorsagia circumcincta in Romanov sheep using natural or artificial challenge

et al. 2004

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This experiment was conducted to assess the efficiency of selection on the basis of response to artificial challenges in order to breed sheep resistant to natural infection. A shortterm divergent selection process was designed to estimate the genetic parameters of these two traits. Two flocks, including 100 Romanov ram lambs each, were challenged in 1990 when they were 6 months old. One flock received three artificial infections with 20 000 third-stage Teladorsagia circumcincta larvae, at intervals of 7 weeks. Faecal egg counts (FEC) were performed on Days 22, 25 and 28 post infection (p.i.) and the animals were drenched on Day 28 p.i. The other flock was grazed for 5 months on a pasture contaminated with the same species. Faecal samples were taken from the lambs at similar ages. About 5 rams with the lowest FEC and 5 with the highest FEC were selected in each flock and mated with unselected ewes. Their offspring (200 animals) were challenged in 1992, half in the same way as their sires, and the other half by the other method. Because of a drought in the summer of 1990, it was necessary to repeat part of the experiment, and in 1992 the 5 and 8 rams with the lowest and highest FEC, respectively, were selected from the offspring challenged on the pasture in 1992 and were mated with unselected ewes. Their progeny (about 80 animals) were challenged in 1994, half by natural infection, half by artificial infection. The mean FEC of the flock increased from the first to the third artificial infection. The natural infection was highly variable in different years, reflecting the difficulty of assessing resistance using this mode of challenge. Genetic parameters were estimated using animal models and REML solutions. The repeatabilities of the FEC following

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Resistance to experimental infections with Haemonchus contortus in Romanov sheep

Cited by 3 publications

References 16 publications

Structure of European ovine populations from directional autocorrelations between proteins

Structure of European ovine populations from directional autocorrelations between proteins

Fecal egg counts for gastrointestinal nematodes are associated with a polymorphism in the MHC-DRB1 gene in the Iranian Ghezel sheep breed

A short-term divergent selection for resistance to Teladorsagia circumcincta in Romanov sheep using natural or artificial challenge

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