New Zealand Journal of Agricultural Research abstracts
Effect of sward density and size of faecal deposit on the
development and persistence of third-stage Trichostrongylid larvae of
sheep
R. A. Moss
New Zealand Pastoral Research Institute
PO Box 60
Lincoln 7640, New Zealand
A. R. Bray
Meat and Wool New Zealand
PO Box 121
Wellington 6140, New Zealand
Abstract Ryegrass swards of low and high density
were established to which lamb faeces containing nematode eggs were
uniformly applied. This was done as either large or small deposits with
all plots receiving the same quantity. Herbage was cut at 15 mm above
ground level on five occasions over the following 29 weeks and nematode
larvae extracted. The lower sward density plots produced less dry
matter during the first 12 weeks after establishment but subsequently
out-yielded those sown at the high density. When assessed over 36 weeks
post-sowing, initial density had no effect on production. Overall,
larval recovery equated to less than 0.5% of eggs applied. Numbers
peaked between 67 and 147 days after application then declined and were
extremely low by Day 200. Compared to low density, high density swards
yielded the highest number of larvae overall. Sward density during the
first 67 days after faeces were deposited had a greater effect on
larval development, survival and persistence than subsequent
differences in sward characteristics. The larger faecal deposits
resulted in higher numbers of larvae. Effects of increasing sward
density and faecal deposit size were cumulative.
Keywords endoparasites; larvae; nematodes; sward
density; faecal deposits; microclimate; herbage mass; sheep
A05040; Online publication date 26 October 2006 Received 20
September 2005; accepted 29 September 2006
New Zealand Journal of Agricultural Research, 2006, Vol. 49:
475–481
0028–8233/06/4904–0475 © The Royal Society of New Zealand
2006
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