Haemonchus contortus and Trichostrongylus colubriformis are the most important gastrointestinal nematodes causing serious losses in sheep production of tropical and subtropical regions. Prophylaxis of gastrointestinal nematode infections is based on anthelmintics use, but their frequent administration selects multiple-resistant parasites. To evaluate how the situation has changed over the last decades, the anthelmintic resistance status of gastrointestinal nematodes in sheep flocks was assessed in the current study and compared to previous surveys. In each one of the 15 flocks evaluated, animals (n ≥ 7) were allocated into at least five groups and treated as follows: 1) untreated control; 2) albendazole; 3) levamisole; 4) ivermectin; and 5) monepantel. If more animals were available, two additional groups were included: 6) closantel, and 7) moxidectin. The faecal egg count reduction test (FECRT) was carried out to evaluate the pre- and post-treatment using the SHINY tool. Haemonchus spp. was the most prevalent nematode from faecal cultures. The mean efficacy of albendazole was 40%. Only in two farms, levamisole presented a relatively high percentage of reduction in the FECRT about 90%, while ivermectin and moxidectin presented the worst mean efficacy of 34% and 21% among all farms, respectively. Like other anthelmintics, closantel demonstrated low efficacy (63%) across all farms evaluated. Monepantel presented an overall mean efficacy of 79%, but it was the only anthelmintic that presented efficacy ≥95%, in five farms. The results revealed that gastrointestinal nematodes with multiple anthelmintic resistance were prevalent in all 15 sheep herds. The research suggests that nematodes are becoming more and more resistant to various anthelmintic compounds, which has made the problem worse. This circumstance highlights the necessity to put into practice sustainable and long-lasting methods to prevent gastrointestinal nematode infections in sheep husbandry.

This study aimed to evaluate the potential benefits and feasibility of adding dried and ground grape pomace to the concentrate fed to lambs experimentally infected with Haemonchus contortus. Eighteen male Santa Inês lambs, recently weaned, were housed in individual pens and were allocated into two groups based on their body weight. The lambs in the supplemented group (n = 9) initially received a diet composed of 50% ground hay and 50% concentrate. Subsequently, these animals were gradually adapted to grape pomace until its final inclusion in the concentrate reached 20%. The lambs in the control group received a concentrate without grape pomace. Both groups of lambs were artificially infected with 4000 infective larvae of H. contortus, and 28 days later, the lambs were euthanized for quantification of the nematodes present in the abomasum. The following variables showed no statistical differences (p > 0.05) between the groups: worm burden, packed cell volume, total plasma protein, blood eosinophil count, and daily weight gain. Regarding anti-Haemonchus IgG plasma levels, there was a significant time * treatment interaction (p = 0.0099) with higher values in the supplemented group. At the two final samplings, the supplemented group showed significantly lower values of eggs per gram of feces than the control group (p < 0.05). The supplemented group showed female worms shorter and with less eggs in utero than those of the control group, with significant difference for these variables (p < 0.05). In conclusion, grape pomace can be included in the diet, as it promotes more sustainable animal production, and, additionally, it can cause a reduction in H. contortus fecundity, benefiting haemonchosis prophylaxis.

This study evaluated the feasibility of including grape pomace in the diet of Santa Inês ewes during lactation, aiming to reduce the effects of gastrointestinal nematode (GIN) infections and improve productive performance. Grape pomace, which contains phenolic compounds and tannins, was provided as a dietary supplement, replacing 20% of the concentrate over 28 days of lactation, starting on day 7 after lambing. A total of 18 ewes were used, divided into two groups: supplemented (n = 8) and control (n = 10). The supplemented group showed significant reduction in fecal egg count on day 14 of lactation (p < 0.05) in comparison with the control group. Lambs from the supplemented group had higher weaning weights (p < 0.05). Additionally, the supplemented group showed higher values for packed cell volume and circulating eosinophils, indicating greater resilience to infections. Analysis of anti-L3 IgG against Haemonchus contortus revealed no significant differences between the groups. It is concluded that grape pomace supplementation demonstrated potential to improve hematological and productive parameters in lactating ewes, with more evident effects during early lactation. Although the results suggest a possible complementary role in controlling gastrointestinal nematodes, future studies are needed to confirm and optimize this nutritional strategy.

Cattle ranching in Brazil has long been one of the main and most important sectors of the economy. Among the factors that negatively influence the rearing of production animals, the worm disease deserves prominence, because it is one of the most important problems of the Brazilian herd, being responsible for large losses in livestock activity. Worms are caused by helminths of different phyla, classes, genera and species, and can affect several animals, being extremely important in production animals. These parasites can cause losses and great economic losses due to the fall in animal production and costs with its control. The administration of anthelmintics in the correct dosage is of great importance, because its misuse is probably one of the causes that accelerate the emergence of resistant helminth populations. However, when done incorrectly and indiscriminately, it can lead to inefficiency of the drugs because with the wrong management of these drugs there is a selection of resistant parasites. In view of the above, the objective of this literature review was to gather information on ways to control helminthiases and some alternatives that have been studied to improve livestock production systems. Keywords: Anthelmintics; Helminths; Nematodes.

Anais do International Meeting of Agrarian Science and Technology (978-65-5941-383-6) - Eficácia Da Ivermectina Sob Diferentes Formulações E Vias De Administrações Em Equinos

Objetivou-se avaliar o grau de helmintose, ganho de peso e parâmetros hematológicos de bezerros Nelore, fêmeas e machos, oriundos de matrizes do mesmo rebanho previamente classificadas por diferentes níveis de infecção parasitária. Os animais foram divididos conforme a classificação de suas mães, sendo filhos de resistentes (G1), resilientes (G2) e susceptíveis (G3). As fezes foram coletadas a cada 28 dias para a contagem de ovos por grama de fezes (OPG), coprocultura e identificação das larvas. As pesagens foram realizadas a cada 28 dias, após o desmame e as coletas de sangue, no início e no término do experimento para determinar o volume globular, proteína plasmática total e contagem de eosinófilos do sangue. O resultado obtido para OPG demonstrou que não houve diferença significativa entre G1, G2 e G3. No período de três a oito meses de idade, o OPG dos bezerros machos também não apresentou diferença entre os grupos, já as bezerras filhas de vacas previa[i]mente classificadas como susceptíveis (G3) apresentaram um OPG superior em relação às filhas das resistentes e resilientes (G1 e G2). Em relação ao peso, houve diferença significativa no GPD geral (machos e fêmeas), onde os animais do G3 apresentaram um menor GPD em relação aos demais grupos, já o G1 e G2 não apresentaram diferença significativa. Nos parâmetros hematológicos não houve diferença nos parâmetros avaliados. Nas coproculturas, em todos os grupos foram encontradas larvas de Cooperia spp., Haemonchus spp. e Oesophagostomum spp.. Conclui-se que bezerras filhas de vacas susceptíveis podem sofrer influência de suas mães em relação a carga parasitária e assim, redução em seu desempenho produtivo. Já bezerros machos não sofreram influência de suas mães no grau de helmintose e desempenho.