A comparison of internal parasitism in fleeceweight-selected and
control Romney sheep
S.W. Howse, H.T. Blair, D.J. Garrick, W.E. Pomroy
Department of Animal Science, Massey University, Palmerston
North, New Zealand
Proceedings of the New Zealand Society of Animal Production.
1992, 52: 57-60
This trial was designed to test the hypothesis that increased
faecal egg counts (FEC) of fleeceweight-selected (FW) lambs over
control (C) lambs represented a decreased resistance to internal
parasitism in FW lambs. Measurements were recorded over a 42 day period
from late February 1991 using August-born lambs from the Massey
University FW and C flocks. All lambs were drenched with ivermectin on
day 0. Lambs of each sex and flock were randomly allocated within sire
(4 per flock) to receive an albendazole controlled release capsule
(+ALB). Ewes and rams were run separately. Midside wool growth,
liveweight, and FEC were recorded, and estimates of dry matter intake
were inferred from chromate analyses.
The FW lambs had consistently higher FEC's than C lambs. Significant
differences were observed by flock and ALB treatment in both wool
production and liveweight gain, but no significant flock-by-ALB
interaction were detected. Trends in production traits indicated that
the superiority of FW lambs may have increased in situations where the
development of adult worm burdens was continually suppressed. However,
no clear evidence was found to show that FEC is a reliable indicator of
a sheep's resistance to production losses arising out of internal
parasitism.
Keywords: NZSAPAB;
Lambs; internal parasites; faecal egg count; liveweight gain;
wool production.
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Last Updated 25-01-1997
