Internal parasites and lamb production - a role for plants containing
condensed tannins?
J.H. Niezen, T.S. Waghorn, G.C. Waghorn, W.A.G. Charleston
AgResearch, Flock House Agricultural Centre, Private Bag 1900, Bulls,
New Zealand
Proceedings of the New Zealand Society of Animal Production. 1993,
53: 235-238
Three experiments were undertaken to investigate the possibility that
forages containing condensed tannins (CT) may affect nematode parasite
burdens and their significance in lambs. In the first trial, lambs were infected
with a single dose of 15000 Ostertagia circumcincta and 15000
Trichostrongylus colubriformis infective lavae. Those fed Lotus
pedunculatus with or without polyethylene glycol (PEG) had lower faecal
egg counts, higher liveweight gains and higher faecal dry matters than lambs
fed ryegrass with or without PEG (P<0.05). In the second experiment, lambs
with a low, mixed natural worm burden were grazed on sulla
(Hedysarium coronarium), a CT containing legume, or lucerne, for 28
days. Lambs drenched with anthelmintic and fed sulla grew faster than those
fed lucerne (321 v 215 g/day P<0.05) whilst undrenched lambs had similar
growth rates on both species (250 v 220 g/day). In the third experiment,
heavily parasitized lambs sired by rams selected for low faecal egg count
(resistant) or conventional rams (non-resistant) were grazed on lucerne or
sulla for 28 days. When anthelmintic drenches were withheld, the non-
resistant sired lambs grew faster on sulla than lucerne (231 v 28 g/day;
P<0.0001), as did the resistant sired lambs (181 v 72 g/day; P<0.001)
respectively. Drenched non-resistant sired lambs grew faster on the sulla than
on lucerne and faster than the resistant sired lambs.
These results suggest that forages containing condensed tannins may have an
important role to play in developing lamb production systems with less
reliance on anthelmintic use for parasite control.
Keywords: NZSAPAB;
Lambs; parasitism; nutrition; condensed tannins.
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Last Updated 25-01-1997
