ESTABLISHMENT AND FECUNDITY OF OSTERTAGIA-CIRCUMCINCTA AND TRICHOSTRONGYLUS-COLUBRIFORMIS IN LAMBS FED LOTUS (LOTUS-PEDUNCULATUS) OR PERENNIAL RYEGRASS (LOLIUM-PERENNE)

Forty four 12-14 week old Polled Dorset ram lambs, raised helminth fre e from birth, were used to investigate the effects of condensed tannin s (CT) in lotus (Lotus pedunculatus) on lamb growth and gastrointestin al nematode establishment and fecundity. Condensed tannins bind to pro teins in the rumen and increase the flow of protein to the intestines. Lambs were allocated to either a ryegrass (Lolium perenne) or lotus d iet fed ad libitum, with or without twice daily drenching of polyethyl ene glycol (PEG) which binds with and deactivates the CT. One week aft er allocation to the diets, each lamb was infected per os with 10 000 Ostertagia circumcincta and 10 000 Trichostrongylus colubriformis larv ae and slaughtered 28 or 29 days later. Lambs fed lotus had lower faec al egg counts (P<0.0001) and lower O. circumcincta burdens (P<0.001), fewer female O. circumcincta (P<0.001) and higher faecal dry matter (P <0.001) than lambs fed ryegrass, but numbers of T. colubriformis nemat odes were not affected. This trial did not ascribe beneficial effects of L. pedunculatus to CT per se and the use of PEG does not seem appro priate to studies of parasitology. (C) 1998 Elsevier Science B.V.