Finishing lambs on a chicory-plantain mixture or a temperate grass-based pasture: live weight gain and gastrointestinal parasitism
Abstract Improved plantain (Plantago lanceolata L.) and chicory (Cichorium intybus L.) are attractive forage species for finishing lambs and contain compounds that might protect sheep from gastrointestinal nematodes. This study compared the live weight gain and parasite burden of weaned lambs finished on a plantain-chicory mix (Pl-C) or a permanent grass-based pasture (PP) and treated with or without an endectocide. From mid-November, weaned lambs (n=72, average live weight 32 kg) were distributed into three paddocks per sward type for 30 d. Half of the lambs were initially treated with ivermectin. Fecal egg counts (FEC), larvae genera and the presence of infective larvae (L3) in pastures were evaluated. No differences (P>0.05) were obtained between the pastures for the initial (ca. 80 epg) or final FEC (322 epg) or type of eggs (Strongylid- or Nematodirus-type). Ivermectin treatment reduced (P<0.01) the total FEC (482 vs. 158 epg) and the Strongylid- (418 vs. 148 epg) and Nematodirus-type eggs (64 vs. 9 epg). No significant effects (P>0.05) of pasture type or anthelmintic treatment and no interactions were detected on the cultured larvae genera, except for Cooperia, which decreased with the anthelmintic treatment. By day 30, the number of L3 recovered from the pastures increased (P<0.05) in the PP (62 to 280 L3 kg-1 DM), while the number was unchanged (P>0.05) in the Pl-C (average 63 L3 kg-1 DM). The parasite load estimated by the FEC reached low infection levels (<400 epg), preventing clinical signs. The live weight gain of lambs was similar (P>0.05) among treatments (average 173 g d-1), reflecting an adequate nutritional quality of both pastures and a moderate parasitism status of the lambs.