English   español  
Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/144487
Share/Impact:
Statistics
logo share SHARE logo core CORE   Add this article to your Mendeley library MendeleyBASE

Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL
Exportar a otros formatos:

Title

Implementation of an extended ZINB model in the study of low levels of natural gastrointestinal nematode infections in adult sheep

AuthorsAtlija, M.; Prada, J. M.; Gutiérrez Gil, Beatriz; Rojo Vázquez, Francisco Antonio ; Stear, M. J.; Arranz, Juan José; Martínez Valladares, María
KeywordsIgA
ZINB
Prevalence
Sheep
Gastrointestinal nematodes
Egg count
Issue Date2016
PublisherBioMed Central
CitationBMC Veterinary Research 12 (2016)
AbstractBackground: In this study, two traits related with resistance to gastrointestinal nematodes (GIN) were measured in 529 adult sheep: faecal egg count (FEC) and activity of immunoglobulin A in plasma (IgA). In dry years, FEC can be very low in semi-extensive systems, such as the one studied here, which makes identifying animals that are resistant or susceptible to infection a difficult task. A zero inflated negative binomial model (ZINB) model was used to calculate the extent of zero inflation for FEC; the model was extended to include information from the IgA responses. Results: In this dataset, 64 % of animals had zero FEC while the ZINB model suggested that 38 % of sheep had not been recently infected with GIN. Therefore 26 % of sheep were predicted to be infected animals with egg counts that were zero or below the detection limit and likely to be relatively resistant to nematode infection. IgA activities of all animals were then used to decide which of the sheep with zero egg counts had been exposed and which sheep had not been recently exposed. Animals with zero FEC and high IgA activity were considered resistant while animals with zero FEC and low IgA activity were considered as not recently infected. For the animals considered as exposed to the infection, the correlations among the studied traits were estimated, and the influence of these traits on the discrimination between unexposed and infected animals was assessed. Conclusions: The model presented here improved the detection of infected animals with zero FEC. The correlations calculated here will be useful in the development of a reliable index of GIN resistance that could be of assistance for the study of host resistance in studies based on natural infection, especially in adult sheep, and also the design of breeding programs aimed at increasing resistance to parasites.
Description9 páginas, 4 Figuras, 1 Tabla.
Publisher version (URL)http://dx.doi.org/10.1186/s12917-016-0723-7
URIhttp://hdl.handle.net/10261/144487
DOI10.1186/s12917-016-0723-7
ISSN1746-6148
Appears in Collections:(IGM) Artículos
Files in This Item:
File Description SizeFormat 
Atlija et al_ BMC Veterinary Research (2016).pdf1,36 MBAdobe PDFThumbnail
View/Open
Show full item record
Review this work
 

Related articles:


WARNING: Items in Digital.CSIC are protected by copyright, with all rights reserved, unless otherwise indicated.