Integrated Tick Management of the Winter Tick, Dermacentor albipictus (Acari: Ixodidae), in Grazing Cattle Systems
Abstract
The winter tick, Dermacentor albipictus Packard (Acari: Ixodidae), is a one-host tick species that parasitizes large ungulate hosts during fall and winter months when annual forage quality and quantity are low. Larvae remain inactive in clusters through the summer months to avoid unfavorable environmental conditions, a critical link in year-to-year infestations. Dermacentor albipictus is a biological vector of Anaplasma marginale Theiler, causal agent of bovine anaplasmosis, an important disease of Texas beef cattle. Tick control through Integrated Pest Management (IPM) strategies include habitat and wildlife management, grazing rotations, and cattle treatments with acaricides. Near infrared reflectance spectroscopy of bovine feces (fNIRS) may offer a non-invasive, economical, and efficient means of detecting tick infested animals. Investigations were conducted to 1) determine if artificial infestations of D. albipictus could be detected in cattle using fNIRS and if detection capability was sensitive to size of tick infestation and phase of on-host stage-specific tick development, 2) assess producer adoption of near infrared reflectance spectroscopy (NIRS) technology in grazing cattle systems, and 3) compare survivorship of D. albipictus larvae exposed to different saturation deficit environments in long-day and short-day photoperiods.
Cattle with D. albipictus infestations arising from as few as 1000 larvae were identified by fecal chemistry changes using fNIRS technology. In two separate trials, three animal pairs were infested with one of three treatment levels of D. albipictus larvae in a repeated measures experimental design. Significantly different fecal sample-cluster shifts occurred between two periods of pre-infestation, three stages of tick development, and a post-tick recovery period. Results from beef cattle producers surveyed at extension workshops over three years characterized the enterprises of audience participants and found willingness for potential adoption of NIRS technology. Larval survivorship was highly associated with saturation deficit. As saturation deficit decreased, survivorship increased regardless of photoperiod treatment. Collectively, these results may guide future studies to determine the best IPM strategies for control of D. albipictus and the use of fNIRS to detect tick infestations in grazing cattle systems. Results may also guide extension program development to demonstrate best practices on new approaches and technologies that improve tick control.
Citation
Hays, Samantha Rae (2021). Integrated Tick Management of the Winter Tick, Dermacentor albipictus (Acari: Ixodidae), in Grazing Cattle Systems. Doctoral dissertation, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /195788.