Can integrated crop-livestock systems reduce tick infestation in cattle?

Abstract

High levels of cattle tick (Rhipicephalus microplus) infestation cause production losses and increase livestock costs. Based on the hypothesis that the space-time rotation characteristic of integrated crop-livestock systems (ICLS) decreases tick populations in pastures and, consequently, reduces cattle infestation, this study evaluated infestation score (IS), number of acaricide applications (NAA), and average daily weight gain (ADWG) of beef steers grazing under four ICLS. The study was carried out with Angus steers in southern Brazil over three consecutive years (2017-2020). Animals were managed under continuous stocking in four systems: crop-livestock (CL), livestock-forestry (LF), crop-livestock-forestry (CLF), and livestock only (L). Tick infestation was assessed fortnightly (IS 0-4), and ADWG was obtained every 28 days. Animals in CL and CLF showed 17.6% and 29.4% lower IS compared with L and LF, respectively, resulting in proportionally fewer individual acaricide applications. Despite differences in infestation, ADWG did not vary among production systems. Seasonal effects were evident, with higher IS and NAA in summer. Logistic regression indicated that steers with high IS (3-4) were 12.6 times more likely to lose weight than those with lower IS (0-2). A progressive reduction in ADWG occurred as IS increased, suggesting that intervention at IS = 2 (5-10 adult ticks on one body side) may prevent performance losses. Space-time rotation in ICLS disrupts the free-living phase of R. microplus, reducing infestation and chemical use without impairing cattle productivity. ICLS combined with selective treatment represents a sustainable strategy for tick control in grazing systems.