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

Published online by Cambridge University Press:  08 December 2011

H. A. Saddiqi ,
M. Sarwar ,
Z. Iqbal ,
M. Nisa  and
M. A. Shahzad
H. A. Saddiqi*
Affiliation:
Department of Zoology, GC University, Faisalabad 38040, Pakistan
M. Sarwar
Affiliation:
Institute of Animal Nutrition and Feed Technology, University of Agriculture, Faisalabad 38040, Pakistan
Z. Iqbal
Affiliation:
Department of Parasitology, University of Agriculture, Faisalabad 38040, Pakistan
M. Nisa
Affiliation:
Institute of Animal Nutrition and Feed Technology, University of Agriculture, Faisalabad 38040, Pakistan
M. A. Shahzad
Affiliation:
Institute of Animal Nutrition and Feed Technology, University of Agriculture, Faisalabad 38040, Pakistan
*
†E-mail: [email protected]
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Abstract

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.

Keywords

gastrointestinal nematodesresistance potentialsmall ruminantsevaluationparameters
Type
Full Paper
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animal , Volume 6 , Issue 6 , June 2012 , pp. 994 - 1004
Copyright
Copyright © The Animal Consortium 2011

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