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ARS Home » Northeast Area » University Park, Pennsylvania » Pasture Systems & Watershed Management Research » Research » Publications at this Location » Publication #148895
Title: SIMULATING DETECTION OF CATTLE-FEVER TICK (BOOPHILUS SPP.) INFESTATIONS IN ROTATIONAL GRAZING SYSTEMS

Author
item Corson, Michael
item TEEL, P - TEXAS A&M
item GRANT, W - TEXAS A&M

Submitted to: Ecological Modeling
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/12/2003
Publication Date: 9/15/2003
Citation: Corson, M.S., Teel, P.D., Grant, W.E. 2003. Simulating detection of cattle-fever tick (Boophilus spp.) infestations in rotational grazing systems. Ecological Modeling. 167(3):277-286.

Interpretive Summary: Cattle-fever ticks, eradicated in the United States, sometimes return to the U.S. on cattle from Mexico. Detecting these ticks on cattle represents an important part of the programs that keep cattle-fever ticks from re-infesting U.S. rangelands. We modified a computer model to see how weather, vegetation, and rotational grazing strategies may affect the chance of detecting ticks on cattle in south Texas. Results indicate that probability of detecting infestations depends most on season of initial infestation; less heavily on rotational grazing strategy, habitat type, and number of cows inspected; and only moderately on initial number of infesting tick larvae. If adjusted for a specific climate and rotational grazing cycle, this model could be used to indicate when inspectors may have the best chances to detect cattle-fever-tick outbreaks.

Technical Abstract: To evaluate the relative influence of ecological and management factors on the probability of detecting cattle-fever tick (Boophilus microplus and B. annulatus) infestations in rotational grazing systems, we adapted a simulation model of Teel et al. (1998) that examines interactions among Boophilus ticks, cattle, and habitat type under rotational grazing systems developed for semi-arid shrublands of south Texas. We added a submodel that estimates probability of inspectors detecting Boophilus-tick infestations when examining 1, 20, 40, or 80 cows in a tick-infested herd of 80 cattle. Results indicate that probability of detecting infestations depends most on season of initial infestation; less heavily on rotational grazing strategy, habitat type, and number of cows inspected; and only moderately on initial number of infesting tick larvae. Results showed high detection probabilities ( 0.95) usually exist as temporal windows of opportunity during brief but definite periods; outside these windows, detection of existing infestations becomes poor. Each halving of the number of cows inspected tended to shorten duration of these windows by approximately 40%. Probability of detecting tick infestations, however, also depends strongly on inspector training, cow behavior, and weather, factors that we set as implicit constants. Models such as this one can indicate gaps in knowledge about the influence of biophysical and human factors on detection efforts in tick eradication or control programs, estimate magnitude and duration of Boophilus-tick infestations, and indicate potentially favorable inspection periods.