Abstract The objective of this study was to evaluate high-concentrate diets and two energy sources on intake, performance and meat quality parameters of feedlot Nellore heifers. Twenty-eight heifers (200 ± 22.5 kg BW) were randomly assigned to four treatments in a 2×2 factorial arrangement: two concentrate levels (70 and 80%) and two energy sources (corn and corn germ meal). At the end of day 112, heifers were slaughtered. There was no interaction (P>0.05) of concentrate levels and energy sources for dry matter intake, unlike crude protein (CP) and neutral detergent fiber (NDF) intakes. The concentrate level of 80% and corn, allowed the highest CP (1.17 kg/day) and NDF (4.05 kg/day) intakes. Final BW (P<0.05) and daily gain (P<0.01) were influenced just by energy source. The carcass composition represented by muscle and fat was affected by concentrate level (P<0.05). Treatments affected (P<0.01) carcass fat deposition, global preference and texture of Longissimus muscle (P<0.05). It was concluded that high proportions of concentrate containing corn as energy source provided the best performance in heifers, and that the total replacement of corn with corn germ meal in high-concentrate diets is not recommended for performance Nellore heifers, but provided good sensory quality to the meat.

RESUMO Objetivou-se com este estudo avaliar a eficácia do princípio ativo oxfendazole e da associação deste com o levamisol, na redução de ovos por gramas de fezes (OPG) e de larvas de helmintos nas fezes de cabras sem padrão racial definido (SPRD) criadas em pasto sob pastejo contínuo de Capim Colonião (Panicum maximum), bem como o tempo de ação após a aplicação dos medicamentos. Os tratamentos experimentais foram: animais não desverminados (ND); animais desverminados com oxfendazole (DO); e animais desverminados com associação de oxfendazole e levamisol (DOL). Entre os grupos tratados, o grupo em que as cabras foram submetidas à associação dos princípios ativos (DOL) mostrou-se 16,75% mais eficaz comparado ao grupo tratado com oxfendazole (DO). Houve um pico de redução de larvas de Haemonchus eTrichostrongylus no terceiro e nono dia, respectivamente, após a aplicação do anti-helmíntico, em relação ao dia da vermifugação. Apesar disso, até o nono dia não foi observado eficácia acima de 95%, podendo considerar uma provável resistência aos princípios utilizados. Embora não tenha atingido a eficácia esperada, esta associação foi mais eficaz na redução de larvas do gênero Trichostrongylus, quando comparado à utilização do composto químico isolado, podendo ser uma alternativa à recomendação da associação de anti-helmínticos no controle de infecções gastrintestinais em cabras criadas em regime de pasto.

SUMMARY This study aimed to evaluate the effectiveness of the active ingredient oxfendazole and the association of this with levamisol, reduction of eggs per gram of feces (EPG) and larvae of helminths in the feces of goats without defined breed (SPRD) created pasture under continuous grazing grass (Panicum maximum), and the action time after application of medicines. The treatments were: no animals wormed (ND); animals wormed with oxfendazole (DO); and animal wormed with oxfendazole association and levamisole (DOL). Between the treated groups, the group where the goats were submitted to association of active ingredients (DOL), was shown to be 16.75% more efficient compared to the group treated with oxfendazole (DO). A peak reductionTrichostrongylus and Haemonchus larvae at 3th and 9th days, respectively, after application of an anthelmintic in relation to worming day. Nevertheless, until the 9th day was not observed efficacy above 95%, can be considered a likely resistance to the principles used. Although it has not reached the expected efficacy, this combination was more effective in reducing larvae of Trichostrongylus genus, when compared to isolated use of the drug. Could be an alternative to the recommendation of anthelmintics association in the control of gastrointestinal infections in goats raised on pasture.