Uso do tratamento seletivo como método de controle das parasitoses gastrintestinais de caprinos no Brejo paraibano.

Abstract

For decades, anthelmintics have been used efficiently to control gastrointestinal parasites in goats and sheep, however, the natural consequence of the indiscriminate use of these compounds has led to the development of anthelmintic resistance. In the UFPB Caprinoculture Sector, problems with gastrointestinal parasites have been recurring. This information led to the suspicion that errors were occurring in relation to antiparasitic management, demonstrating the need to conduct a study to evaluate the measures used and install a form of selective treatment as an auxiliary measure in the control. Information on antiparasitic management was obtained through visits to the sector. To evaluate the occurrence of anthelmintic resistance and to identify the active ingredient that would be used in selective treatment, effectiveness tests were performed. The animals were evaluated over a

period of 15 months. The study herd consisted of 40 adult Saanen goats, raised in a semi- intensive manner. During the day the animals grazed in paddocks of Brachiaria decumbens.

Four paddocks of around 1 hectare each were made available, with rotation being made according to the availability of the grass. Most evaluations followed intervals of 30 days. There were no outbreaks of parasites and animal deaths in the period. The study identified that pastures are likely to be important sources of contamination for animals, that excessive use of worms was occurring and that there was multiple resistance to anthelmintics. In the first parasitological exams performed, to evaluate the effectiveness of the active ingredients, it was possible to identify that 22 (55%) of the animals had a parasitic load above 500 OPG of feces, with animals with up to 6250 OPG being identified. In the co-culture, the predominance of the genera Haemonchus (80%), Trichostrongylus (12%), Oesophagostomum (6%) and Cooperia (2%) was found. The test to reduce the egg count per gram of feces performed to assess the efficacy of the drugs identified 44% efficacy for albendazole, 31% for levamisole, 53% for doramectin and no efficacy for ivermectin. The principle used in selective treatment was doramectin. During the evaluation period, 4 (11%) animals received 1 dose, 6 (17%) received 2 doses, 2 (5.5%) received 3 doses, 3 (8.3%) received 4 doses, 3 (8, 3%) received 5 doses, 3 (8.3%) received 6 doses, 4 (11%) received 7 doses, 4 (11%) received 8 doses and 2 (5.5%) received 9 doses. In the first year of the study, there was a 61.2% reduction in the use of vermifuge. It is concluded that the lack of an integrated parasite control favors the occurrence of gastrointestinal parasites in the studied herd, that the selective treatment allowed an important reduction in the use of vermifuge and prevented outbreaks of gastrointestinal parasites and deaths. However, the choice of the active ingredient to be used in selective treatment must be very careful, and further studies are needed to clarify the behavior of drugs in herds that already show some resistance.