Dispersal and concentration of sheep gastrointestinal nematode larvae on tropical pastures Academic Article uri icon


  • 2019 Elsevier B.V. Knowledge of free-living stages of endoparasite population ecology may guide their control in domesticated ruminants. Our objective was to evaluate sheep gastro-intestinal nematode (GIN) L3 distribution in tropical pasture profiles (grass and legume). Three different swards (treatments) were compared: 1) grass-only (G), 2) legume-only (L), and 3) one half of the paddock with grass and another half with legume (GL). We assessed pasture larval counts (PLC) in upper, medium and bottom strata, each representing one third of the sward height. Lamb health and performance characteristics were also evaluated. The PLC per kg of herbage dry matter (DM) tended to be 129% greater (P = 0.08) in the upper pasture profile compared to the lower stratum in GL pasture. However, the largest PLC dispersed per area (PLC/m) was found (P < 0.01) in the lowest stratum in all pasture types. The overall PLC, averaged over strata, tended to be greatest (P = 0.09) in GL pasture (377 45 L3/kg DM) when compared to G or L pastures (178 13 L3/kg DM and 160 16 L3/kg DM, respectively). The PLC dispersion in the area (L3/m) was not different among pasture types (47.0 4.1 L3/m; P = 0.63). The PLC dispersion by area was negatively correlated with lamb average daily gain (ADG; r = -0.68, P < 0.01) and positively correlated with precipitation (r = 0.78; P < 0.01). No differences among treatments were detected for lamb performance (P = 0.19). All treatments showed high infection rates but L tended to have greater fecal egg counts (FEC; P = 0.062). The GL swards also tended to have 112 and 136% greater (P = 0.09) PLC per kilogram of DM compared to G and L, respectively. The dispersal of larvae by area showed to be an important measure to describe the pasture L3 contamination, it is highly correlated with lamb average daily gain.

published proceedings


author list (cited authors)

  • Tontini, J. F., Espirito Candal Poli, C. H., Hampel, V., Fajardo, N. M., Martins, A. A., Minho, A. P., & Muir, J. P.

citation count

  • 8

complete list of authors

  • Tontini, Jalise Fabiola||Espirito Candal Poli, Cesar Henrique||Hampel, Viviane da Silva||Fajardo, Neuza Maria||Martins, Anelise Afonso||Minho, Alessandro Pelegrine||Muir, James Pierre

publication date

  • May 2019