Vet Parasitol. 2016 Oct 15;229:1-8. doi: 10.1016/j.vetpar.2016.08.027. Epub 2016 Sep 17.
- 1Moredun
Research Institute, Pentlands Science Park, Bush Loan, Penicuik,
Midlothian, UK. Electronic address: dave.mcbean@moredun.ac.uk.
- 2Biomathematics
and Statistics Scotland, James Clerk Maxwell Building, The King's
Buildings, Peter Guthrie Tait Road, Edinburgh, UK.
- 3Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, Midlothian, UK.
Abstract
This
study aimed to investigate the effect of selection for low faecal egg
count (FEC) in Scottish Cashmere goats in comparison to a control line
of unselected goats grazing the same pasture. Goats from generations F2
through to F9 were monitored for FEC, bodyweight, peripheral
eosinophilia and IgG, IgA and IgE response against Teladorsagia
circumcincta from the end of their first grazing season, through winter
housing (during which a single artificial challenge dose of 10,000 drug
susceptible T. circumcincta was given) and the following full grazing
season. The study demonstrated that selected line animals excreted a
significantly lower number of parasite eggs (P<0.01) in the majority
of generations examined. Liveweight productivity was unaffected by
selection. Although selected line animals had greater numbers of
circulating eosinophils in many of the generations (four generations of
males and six generations of females, P<0.05), there was no direct
link between eosinophilia and reduced FEC. Immunoglobulin levels showed
no consistent difference between selected and control lines. IgG, IgA
and IgE levels were not different between lines over the whole dataset
(P>0.05), although the selected line had significantly elevated or
reduced levels (P<0.05) for all three within individual generations.
There were significant associations between increased IgG and reduced
FEC under artificial infection conditions (P=0.02). Increased IgA was
also significantly associated with elevated FEC during the second
grazing season (P<0.001). The study demonstrates that selection
produced a line of goats with consistently reduced FEC compared with
control animals, but did not identify a clear relationship between any
of the immune markers measured and faecal egg output.
Copyright © 2016 Elsevier B.V. All rights reserved.
KEYWORDS:
Gastrointestinal nematodes; Goats; Selection
