Please use this identifier to cite or link to this item:
|Title:||Worm egg count is not associated with greasy fleece weight in sheep phenotypically different for resistance or resilience to gastrointestinal nematodes||Contributor(s):||Kelly, Gareth Andrew (author); Kahn, Lewis (author) ; Walkden-Brown, Steve W (author)||Publication Date:||2011||Handle Link:||https://hdl.handle.net/1959.11/8900||Abstract:||A two-year cross-over experiment investigated phenotypic resistance and resilience to gastrointestinal nematodes (worms) on production characteristics in grazing sheep. On six farms, two mobs (yearling or mixed age) of 300 or more Merino ewes were chosen at shearing in 2007. Within each mob, animals were randomly allocated to receive either normal management (challenged, n=60) or worm-free treatment (n=60) involving suppressive control using combination long acting anthelmintics. Faecal worm egg count (WEC) was measured individually every two months and greasy fleece weight (GFW) at each shearing. Treatments were swapped at shearing in 2008 and continued until shearing 2009. Sheep were placed into quartiles based on either WEC(1/3) (resistance) or GFW (resilience) distributions within their treatment groups when challenged. The effect of resistance (WEC quartile) on challenged and worm-free GFW was analysed using an appropriate general linear model followed by Tukey's HSD test while the effect of resilience (GFW quartile) was analysed by intra-quartile comparison of GFW under worm-free and normal management. More resistant sheep will have a lower requirement for anthelmintic treatment but do not exhibit higher GFW in a challenged environment (Table 1). When worm-free, the most resistant quartile had lower GFW compared to the most susceptible quartile. Increased resilience was not associated with higher WEC. Phenotypic selection for high fleece weight will not increase the need for anthelmintic treatment and improve resilience without adverse effects on worm control.||Publication Type:||Conference Publication||Conference Name:||ICOPA XII: 12th International Congress of Parasitology, Melbourne, Australia, 15th - 20th August, 2010||Conference Details:||ICOPA XII: 12th International Congress of Parasitology, Melbourne, Australia, 15th - 20th August, 2010||Source of Publication:||Proceedings of the XII International Congress of Parasitology (ICOPA)||Publisher:||Medimond||Place of Publication:||Bologna, Italy||Field of Research (FOR):||070708 Veterinary Parasitology
070203 Animal Management
|HERDC Category Description:||E3 Extract of Scholarly Conference Publication||Other Links:||http://www.medimond.com/proceedings/moreinfo/20100815.htm||Statistics to Oct 2018:||Visitors: 176
|Appears in Collections:||Conference Publication|
Files in This Item:
checked on Dec 29, 2018
Items in Research UNE are protected by copyright, with all rights reserved, unless otherwise indicated.