Simulated Cattle Fever Tick Infestations in Rotational Grazing Systems

Abstract

Prior simulation analysis of cattle fever tick population dynamics has indicated that fixed rotation, short duration grazing (SDG) systems could mediite the spread of ticks among pastures if rest periods were greater than 100 to 150 days. A question arose whether variable rotations with rest periods approaching 35-70 days could mediate the spread of ticks within these rapid, rotational grazing systems. An 8-pasture:l-herd extensive (26-34 days:182-238 days graze:rest) and intensive (5-10 days: 35-70 days graze:rest) short duration grazing system was simulated over a 2-year period after a spring and fall introduction of infested animals using a model depicting both temporal and spatial processes involved in host-parasite-landscape interactions. The extensive SDG system was infested for 639 and 424 days for spring and fall introductions, respectively. The intensive SDG system was continuously infested throughout the 24-month simulation. Although the intensive SDG system was continuously reinfested, there were more frequent tick-free periods in the fall introduction than the spring introduction. These simulations indicate that rest periods exceeding 150 days are necessary to minimii the rate and extent of spread of ticks in variable rotational grazing systems. These. considerations are pertinent to the goals of both control and eradication strategies.

Quantitative models of Rhipicephalus (Boophilus) ticks: historical review and synthesis

“…They later adapted it to simulate rotational grazing strategies (Teel et al. , ), acaricide treatments (Corson et al. ), and inspection of cattle for ticks under continuous (Teel et al.…”

“…During this period, researchers from Texas A&M University (TAMU) developed a new model focusing specifically on daily habitat influences on R. microplus and R. annulatus populations in south Texas (Teel et al 1996). They later adapted it to simulate rotational grazing strategies (Teel et al 1997(Teel et al , 1998, acaricide treatments (Corson et al 2001), and inspection of cattle for ticks under continuous ) and rotational grazing. Hern andez-Arrieta et al (2000) adapted the original TAMU model to simulate R. microplus in rotational grazing systems in Venezuela.…”

Tick-borne pathogens, transmission rates and climate change

“…The models did not take into account the effects of habitat fragmentation, or host availability and movement at the scale necessary to evaluate these factors. A quantitative improvement has been achieved with development of a model for the cattle tick that is based on population processes, and includes habitat structure, and host availability and movement (7,8).…”