Effects of daily larval challenge on the performance of breeding
ewes from late pregnancy to post weaning - Brief Communication
R.W. McAnulty, A.S. Familton, A.R. Sykes
Animal and Veterinary Sciences Group, Lincoln University,
Canterbury, New Zealand
Proceedings of the New Zealand Society of Animal Production.
1991, 51: 95-96
Five-year old Coopworth pregnant twin bearing ewes were
allocated to four periods of treatment which commenced either -4, 0, 6
or 12 weeks from lambing periods 1 to 4, respectively. Within each
period, pregnant ewes were further allocated to one of two groups (n+6)
one receiving 4000 Ostertagia(Teladorsagia)
circumcincta larvae per day for 30 days (MCI) or no infection
(NIC). All ewes were housed indoors and offered a pelleted diet.
Faecal egg counts, ewe liveweight, food intake, milk production and
serum pepsinogen were determined weekly. Wool growth, fibre diameter
and tensile strength were determined on wool grown within each
experimental period. Abomasal damage, as judged by serum pepsinogen,
occurred during all periods of infection. The magnitude of production
losses varied with time of challenge. Parasitism reduced milk
production by 10-59% (p<0.01) and wool staple strength by 29-44%
(p<0.01) with greatest effects on wool staple strength being recorded
during period 1. During lactation food intake (p<0.01) was reduced by
30% in period 1 by parasitic infection but little effect was seen prior
to parturition. These data confirm that significant production losses do
occur in breeding ewes. The effects on ewe production of any larval
challenge will depend on the timing of the challenge will depend on the
timing of the challenge and on the susceptibility of the ewe to
infection at that time.
Keywords: NZSAPAB;
Ostertagia; artificial; challenge; parturition; breeding
ewes; nematode; parasites; susceptibility; production loss; tensile
strength
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Last Updated 25-01-1997
