Can the strategies for endoparasite control affect the productivity of lamb production systems on pastures?

ABSTRACT The objective of this study was to evaluate the productivity and carcass traits of unweaned Suffolk lambs finished on pasture and subjected to three strategies for endoparasite control: prophylactic treatment of all animals every 28 days; treatment of animals with a cut off number of nematode fecal egg count (FEC) ≥ 700; and treatment of animals using the FAMACHA scores ≥ 3. Average daily weight gain (ADG) and FEC were evaluated every 14 days for 112 days. Body condition scores and carcass characteristics were assessed before and after slaughter, respectively. Animal productivity was calculated based on animal stocking rate, ADG, and weight variation per area. Animal productivity, pasture, and carcass characteristics did not differ among strategies of parasite control. Parasite control strategies did not affect the productivity of lambs on pasture or carcass characteristics. Thus, the use of selective treatments can be considered advantageous due to decreased selection pressure for resistant parasite populations and lower use of drugs.