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Title: Immune-mediated responses account for the majority of production loss for grazing meat-breed lambs during 'Trichostrongylus colubriformis' infection
Contributor(s): Dever, M L (author); Kahn, Lewis  (author)orcid ; Doyle, Emma  (author)orcid ; Walkden-Brown, Steve W  (author)orcid 
Publication Date: 2016
DOI: 10.1016/j.vetpar.2015.11.017
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Abstract: The hypothesis tested in this experiment was that 'Trichostrongylus colubriformis' infection would reduce growth rates of grazing meat-breed lambs; however production loss would be reduced by suppression of the host immune response. The experiment had a 3 × 2 factorial design using 6-7 month old meatbreed lambs which remained uninfected or infected (IFY) with 2000 or 4000 'T. colubriformis' L3/week for 12 weeks and were immunosuppressed (SUPY) using methylprednisolone acetate once weekly or remained non-immunosuppressed (SUPN). Immunosuppression increased worm egg counts (WEC) of infected lambs (SUPY 2421 eggs per gram (epg), SUPN 1154 epg on day 84, p < 0.05) and 'T. colubriformis' burdens (p < 0.05-0.10) and reduced circulating eosinophils (p < 0.05 on days 11, 42, 56 and 84) and intestinal total antibody titres (p < 0.02). There was a significant (p < 0.05) interaction between the main effects of infection and immunosuppression with infection having a larger negative effect on the liveweight of nonimmunosuppressed lambs. The immunological response of the host to 'T. colubriformis' infection accounted for 75% of the overall cost of infection (3.1 kg) with the majority of this cost occurring during the first 35 days of infection. In contrast, most of the cost associated with the direct effect of infection occurred after day 35. These results confirm in grazing meat-breed lambs that the host's immunological response to 'T. colubriformis' infection is the major component of production loss.
Publication Type: Journal Article
Source of Publication: Veterinary Parasitology, v.216, p. 23-32
Publisher: Elsevier BV
Place of Publication: Netherlands
ISSN: 1873-2550
Fields of Research (FoR) 2008: 070708 Veterinary Parasitology
070205 Animal Protection (Pests and Pathogens)
Fields of Research (FoR) 2020: 300909 Veterinary parasitology
300304 Animal protection (incl. pests and pathogens)
Socio-Economic Objective (SEO) 2008: 830310 Sheep - Meat
830311 Sheep - Wool
Socio-Economic Objective (SEO) 2020: 100412 Sheep for meat
100413 Sheep for wool
Peer Reviewed: Yes
HERDC Category Description: C1 Refereed Article in a Scholarly Journal
Appears in Collections:Journal Article
School of Environmental and Rural Science

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