Field evaluation of integrated tick management strategies, including Allium sativum supplementation, for control of...

Resistance of Rhipicephalus microplus to acaricides is a growing problem for livestock farming, compromising the effectiveness of conventional treatments and increasing production costs. This study evaluated 3% Allium sativum (garlic) dietary supplementation combined with paddock rotation as a complementary strategy for tick control in naturally infested beef cattle under commercial farming conditions in Uruguay. The beef cattle (n = 518; < 2 years old; 245 ± 44.7 kg) were sequentially allocated to six groups, three of which did not have the garlic supplement: ivermectin (IVM, 600 μg/kg, subcutaneous (SC), 3.15%, n = 29), fluazuron (FLU; 2.5 mg/kg, pour- on, 2.5%, n = 30), IVM/FLU (200 μg/kg, 1% + 2.5 mg/kg, SC, 12.5%, n = 278), and three others were moved to a new paddock an administered the garlic supplement (treatments plus): IVM_plus (n = 16), FLU_plus (n = 17), and IVM/FLU_plus (n = 147). An immersion bath using amitraz was applied to all animals 49 days lateR. Tick infestation scores were evaluated over 70 days using an ordinal scale and analyzed via Cumulative Link Mixed Models (CLMM), complemented by in vitro bioassays. Body weight gains and consumption of nutritional blocks were also monitored in the experiment. Up to day 27 in the treatments plus the temporary change in pasture resulted in a reduction of tick infestation and null tick score (range 53% to 82%); however, by day 49, significant reinfestation was observed in all groups, with moderate to high infestation scores (range 40% to 60%). Nevertheless, the predicted probabilities in the treatment of the original paddock increased at low infestation level on 27 and 49 days (range 36% to 46%). Following the application of amitraz, all animals exhibited a null level of infestation, with rates exceeding 97%. The body weight gain was 0.295 kg/day with a mean daily intake of 1.3 g/animal/day of A. sativum. The inclusion of 3% A. sativum supplementation combined with pasture rotation did not demonstrate a clear additional effect for R. microplus control compared to conventional chemical strategies alone.