Estimating genetic differences in natural resistance in Rhön and Merinoland sheep following experimental Haemonchus contortus infection

Gauly, Matthias; Kraus, Matthias H.; Vervelde, Lonneke; Leeuwen, M. A. W. Van; Erhardt, G.

doi:10.1016/s0304-4017(02)00028-6

Cited by 61 publications

(42 citation statements)

References 20 publications

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“…In December the highest FEC (6516) coincided with the high number of specimens of Haemonchus contortus (2814) and the smallest number of C. curticei (2167). In a similar case, a high correlation between worm burdens and FEC (0.64 to 0.73) in Rhön sheep infected with H. contortus was recorded (Gauly et al 2002). Also, a high correlation (0.85 to 0.91) between pre-slaughter FEC and total trichostron- …”

Section: Discussionsupporting

confidence: 48%

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Variability in the fecal egg count and the parasitic burden of hair sheep after grazing in nematode infected paddocks

2013

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Pesq. Vet. Bras. 33(4): 469-475, abril 2013 469 INTRODUCTIONThe frequent and continuous use of chemical anthelmintic drugs for deworming sheep flocks has resulted in the presence of lateral and multiple anthelmintic resistance in the parasites. This resistance leads to a concerning ineffectiveness of anthelmintics with large economic losses in sheep productivity (Coles et al. 2006, Papadopoulos 2008, Sargison 2011. Twenty-four countries have reported the presence of nematodes resistant to several anthelmintics (Jabbar et al. 2006). This situation has motivated workers around the world to search for alternative strategies to Variability in the fecal egg count and the parasitic burden of hair sheep after grazing in nematode infected paddocks 1Roberto González-Garduño 2 *, Pedro Mendoza-de Gives 3 and Glafiro Torres-Hernández 4ABSTRACT.-González-Garduño R., Mendoza- This study aimed to evaluate the variability in the fecal egg count (FEC) and the parasitic burden of naive hair sheep after grazing in nematode infected paddocks. The research was carried out in Tabasco, Mexico, during two periods (August and December). In each period 32 lambs were grazed for one month on African star grass (Cynodon plectostachyus) contaminated with gastrointestinal parasitic nematodes. FEC, packed cell volume (PCV) and body weight (BW) were recorded. Gastrointestinal worms were recovered at necropsy. Data were analyzed with the MIXED procedure of SAS using a model of repeated measurements over time. A higher number of Haemonchus contortus worms was found in December (2814±838) than in August (1166±305). The opposite occurred with Cooperia curticei (2167±393 and 3638±441, respectively). The FEC and correlation coefficient in respect to the worm burden were higher in December (6516 ± 1599, r=0.83, respectively) than in August (4364±771, r=0.44, respectively). A high variability in resistance-susceptibility to gastrointestinal nematodes (GIN) occurred in Katahdin × Pelibuey lambs after grazing.

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Section: Discussionsupporting

confidence: 48%

“…In other studies, PCV and FEC values were observed in Rhön sheep. A correlation range of r= -0.21 to -0.34 (Gauly & Erhardt 2001, Gauly et al 2002, which was lower than those observed in the present study, was found. This can probably be explained because these authors evaluated only the PCV values.…”

Section: Second Periodcontrasting

confidence: 56%

Variability in the fecal egg count and the parasitic burden of hair sheep after grazing in nematode infected paddocks

2013

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“…Mean FEC-6 (5596 6 3078) was lower (P , 0.05) when compared with mean FEC-4 (8134 6 3698; Table 3). This observation agrees with those reported earlier in GM lambs (Gauly et al, 2002). The peak of eggs excretion of H. contortus was observed in the 4th and 5th weeks post-infection in two different breeds (Shakya, 2007).…”

Section: Resultssupporting

confidence: 93%

Is the establishment rate and fecundity of Haemonchus contortus related to body or abomasal measurements in sheep?

Idris

Moors

Budnick

et al. 2011

Animal

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The relationship among parasitological parameters, abomasal size and body size measurements was investigated in lambs following an experimental infection with Haemonchus contortus. In total, 100 lambs from five different genotypes (German Merino (GM), Texel 3 GM, Suffolk 3 GM, German Blackhead Mutton 3 GM and Ile de France 3 GM) were experimentally infected with 5000 infective third stage larvae of H. contortus at the time of weaning at 12 weeks of age. Four and six weeks after infection, individual faecal samples were collected for estimation of faecal egg counts (FECs). Furthermore, wither height, shoulder width, heart girth, loin girth and body length were taken at 18 weeks of life. Lambs were slaughtered and necropsied 7 weeks post-infection, and worm counts, abomasal volume and surface area were determined. Positive correlations were found between different body size parameters, body weight and abomasal sizes. FEC and worm counts were not significantly correlated either with body size parameters or with abomasal size. The mean worm burden was higher in GM than in crossbred lambs. There was no significant difference in abomasal size between GM and crossbred lambs. The results suggest that the variations between animals in worm burden following an experimental infection with H. contortus (worm resistance) are not influenced by body size parameters or abomasal sizes. Therefore, other factors, including genetic-based differences in resistance, must cause these findings between and within breeds.

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“…Worm length is also another valuable parameter to assess the resistant potential of small ruminant flocks and has been used by different workers (Gauly et al, 2002;Saddiqi et al, 2010b). It is the main factor that influences egg production as well as the number of eggs in utero possibly due to IgA (Strain and Stear, 2001).…”

Section: Worm Lengthmentioning

confidence: 99%

Markers/parameters for the evaluation of natural resistance status of small ruminants against gastrointestinal nematodes

Saddiqi¹,

Sarwar

Iqbal

et al. 2012

Animal

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The high prevalence of anthelmintic-resistant gastrointestinal nematodes (GINs) throughout the world has led to the need for alternative worm control strategies. One of the possible substitutes to reduce the problems of drug resistance and residue is the evaluation/breeding of small ruminants for greater resistance to the GINs (organically produced), which in turn would be a helpful tool to predict the performance of an animal. At present, the existing diversity in the genetic potential to resist/tolerate GINs infection both within and between breeds has been validated. Successful selection of animals to define the genotype and identified resistance is related to the employed markers. A number of phenotypic traits such as faecal egg count (FEC), worm burden, serum antibodies, peripheral eosinophilia, packed cell volume, live weight, serum protein and albumin concentrations have been used for this purpose both in natural and artificial infections. Relatively resistant/tolerant animals have also been found to have mastocytosis, globule leucocytes, high levels of histamine and immunoglobulin (Ig) A and IgE concentrations. Of these traits, the principal and most practical measurement used to assess resistance status in animals undergoing similar parasite challenges is FEC. FEC has a positive/negative correlation with other biochemical, cellular and immunological parameters; however, the reliability of individual trial is often questioned and valuable information regarding the genetic makeup can be obtained from pooled data of a large number of trials and parameters. This paper covers all the aspects reported in the literature on various parameters considered to evaluate the resistance status of a range of small ruminant breeds.

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Estimating genetic differences in natural resistance in Rhön and Merinoland sheep following experimental Haemonchus contortus infection

Cited by 61 publications

References 20 publications

Variability in the fecal egg count and the parasitic burden of hair sheep after grazing in nematode infected paddocks

Variability in the fecal egg count and the parasitic burden of hair sheep after grazing in nematode infected paddocks

Is the establishment rate and fecundity of Haemonchus contortus related to body or abomasal measurements in sheep?

Markers/parameters for the evaluation of natural resistance status of small ruminants against gastrointestinal nematodes

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