CONTROLE ESTRATÉGICO DE ENDO E ECTOPARASITOS EM BOVINOS DE CORTE NA FASE DE RECRIA

Abstract

Effective control of endo and ectoparasites in cattle plays a crucial role in livestock production. Endoparasites, such as gastrointestinal nematodes (GINs), can compromise digestive health, while ectoparasites, such as ticks and horn flies, cause discomfort and harm livestock performance. Although there are several strategic measures to control ecto- and endoparasites in isolation, the occurrence of co-infection highlights the need to validate the field, a calendar that aims to simultaneously control endo and ectoparasites. The objective of the present work was to evaluate a strategic protocol for the control of endo- and ectoparasites in cross-bred beef cattle raised on pasture in the tropical region, based on anthelmintic treatments in the dry season and endectocides/ectoparasiticides in the rainy season, and compare it to usual practices in the field. The study was carried out on a rural property located in the municipality of Aquidauana/MS, between May 2022 and March 2023. Using a randomized block design, 60 crossbred cattle (Nelore x Angus) naturally parasitized were divided into two groups: strategic control of gastrointestinal worms, ticks and flies (C3E) and traditional control (CT). The following treatment protocols were evaluated: C3E – May (doramectin 3.5%), August (moxidectin 1%), October (doramectin 3.5%, fluazuron 2.5% and diazinon 45%), December (doramectin 1% and fluazuron 2.5%) and February (fluazuron 2.5%); CT – May (Ivermectin 4%), July (fipronil 1%), October (ivermectin 4% and fipronil 1%) and February (fipronil 1%). In the CT group, the times of ectoparasiticidal treatments (fipronil 1%) were determined by criteria usually adopted on the rural property where the study was carried out and which were representative of usual practices in Brazil. Every 28 days, flies, ticks and fecal eggs (FEC) were weighed and counted. Average daily gain (ADG), live weight gain (LWG) and economic options were determined. Throughout the entire experimental period, no statistically significant differences (p≤0.05) were identified between the OPG means of the C3E and CT groups. However, it is noteworthy that the administration of 1% moxyctin during the dry season contributed to a better performance of the members of the C3E group after this period. Regarding horn flies, cattle subjected to the C3E protocol exhibited lower mean counts (p≤0.05) than those subjected to the traditional protocol in two of the eleven count data (D252 and D280). As for ticks, the mean counts of the C3E group were significantly lower (p≤0.05) than those of the CT group in six of the eleven count data (D28, D112, D196, D224, D252, D280). Thus, the administration of endectocides during critical periods of infestation by endo- and ectoparasites, combined with the use of long-acting ectoparasiticides during the rainy season, proved at the end of the study a better productive performance for the C3E group, evidenced by the superiority in the average gain of final weight of approximately 22.0 kg compared to cattle in the traditional group. Despite the increase in deworming costs by US$3.28 with the C3E protocol, the estimated difference in gross profit was US$35.26, corresponding to an increase in profitability of 12.46% in relation to the traditional system. Furthermore, the return on investment of the C3E group was 10.73 times compared to the CT group. These results validate, under field conditions, the effectiveness of strategic control of endo- and ectoparasites with specific treatments based on the population dynamics and seasonality of NGIs, R. microplus and H irritans in crossbred beef cattle raised on pasture in a tropical region.