Parasitismo gastrintestinal em diferentes intensidades de pastejo no capim Tânzania, em caprinos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Alternativas para o controle de nematoides gastrintestinais de pequenos ruminantes

Sheep and goat farming requires an efficient management program, due to losses caused by parasites in susceptible animals. Many factors may collaborate to improve infection tolerance in the herd, such as: genetics, nutrition, physiological status, and age. The problem caused by resistance to antihelmintic agents has led to the spread of alternative techniques for parasite controls. The latest strategies include selective treatment with the FAMACHA method, phytotherapy, biological control with predatory fungi, and strategies that still await scientific confirmation, such as homeopathy, the dilution of resistance with the introduction of susceptible parasites, and the combination of drugs without antihelmintic effect. The main objective of these methods is to reduce the usage of antiparasitic agents, thus slowing the development of resistance and promoting the better use of effective products and newly released products. The objective of this article is to describe techniques for controlling nematodes in small ruminants, and it is aimed at technicians interested in increasing their knowledge about the mechanisms of resistance to antihelmintic agents as well as alternatives to the use of these products.

Fauna helmintológica de ovinos provenientes da microrregião de Jaboticabal, estado de São Paulo, Brasil

This study evaluated the prevalence and counting parasitism of different species of helminths of sheep from the micro-region of Jaboticabal of Sao Paulo state. For this, 66 animals naturally infected, four to 36 months of age, raised in pasture, were selected. The results of necropsy revealed the presence of seven genera and 12 species with the following prevalence and mean count: Haemonchus contortus: 100.0% (2947.2); Trichostrongylus colubriformis: 90.9% (3048.8); Cooperia curticei: 56.0% (256.5); Oesophagostomum columbianum: 48.4% (36.0); Cooperia punctata: 30.3% (94.5); Trichostrongylus axei: 22.7% (26.5); Strongyloides papillosus: 19.6% (83.0), Haemonchus contortus (L4): 7.5% (17.2), Cooperia pectinata: 10.6% (12.9), Trichuris ovis: 10.6 % (0.6); Cooperia spatulata 4.5% (0.3); Capillaria bovis: 4.5% (0.1). The mean parasitism of helminthswas 6524.7 per animal. Haemonchus contortus (adults and L4) and Trichostrongylus colubriformis corresponded to 45.4% and 46.7% of the average worm burden totally, respectively. Based in the results obtained in this study, can be concluded that the two most abundant species of helminths and important, the micro-region of Jaboticabal are Trichostrongylus colubriformis and Haemonchus contortus, and these two species amounted to 92.1% of the distribution percentage of helminths collected from all animals. These results demonstrate the importance of conducting a counts of eggs per gram of feces (EPG) in the herds of this region when FAMACHA is used on a particular property, since this method control does not allow to diagnostic the damage/clinical signs in animals infected by T. colubriformis, because this specie does not have hematophagism habit on animals.

Performance and parasite control of different genetic groups of lambs finished in irrigated pasture

The aim of this study was to compare the following four genetic groups of hair sheep: Santa Inês (SI), Morada Nova (MN), Brazilian Somali (BS), and the F1 1/2Dorper x 1/2Morada Nova crossbreed on traits related to growth and parasitic infection. Thirty-three male lambs of the same age and of simple birth, under the same pre-weaning management conditions were used in the experiment. After weaning the animals were housed in a completely randomized design in paddocks made of Panicum maximum cv. Tanzania. Along the course of the research, the performance of the four groups of sheep was observed to be negatively affected by gastrointestinal parasites, but there was a genotype effect to the average daily weight gain (ADWG), where the SI and F1 genotypes presented higher values. The effects of genotype, time and genotype x time interaction were significant in weight and corporal score (CS) measurements. The BS lambs had the highest CS values throughout the experiment despite not presenting greater weight gain when compared to the SI and F1 breeds. There were also significant effects of time and genotype x time interaction for packed cell volume (PCV) and FAMACHA© score (FAM) and only the time effect was significant in the total number of eggs per gram (EPG) and total plasma protein (TPP). The MN lambs showed higher PCV values and unlike the other groups, presented a FAMACHA© score below 3 and PCV above 23% even having a higher EPG tendency, especially in the initial phase, indicating a possible higher resilience to infection caused by gastrointestinal parasites.