Analysis of doramectin in the serum of repeatedly treated pastured cattle used to predict the probability of cattle fever ticks (Acari: Ixodidae) feeding to repletion.

Analysis of doramectin concentration in blood serum of pastured cattle injected repeatedly (12 treatments) at two different dosage rates and 28-day intervals throughout the year was used to predict the probability that cattle fever ticks could successfully feed to repletion during the interval between any two consecutive treatments. Treatment at ~270 μg/kg indicated that serum doramectin concentration dropped below the baseline concentration estimated for tick survival (8 ppb) in 7 of the 12 treatments. However, the longest period between any two treatments during which the doramectin concentration remained below the 8 ppb baseline level for successful tick feeding was 15 days, making it virtually impossible for any ticks to reach ovipositional status prior to a subsequent treatment.

Efficacy and blood sera analysis of a long-acting formulation of moxidectin against Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) on treated cattle.

The therapeutic and persistent efficacy of a single subcutaneous injection of a long-acting formulation of moxidectin at a concentration of 1 mg/kg body weight was determined against Rhipicephalus (Boophilus) microplus (Canestrini), along with the concentration-time blood sera profile in treated cattle. The therapeutic efficacy against ticks of all parasitic stages on cattle at the time of treatment was >99.9%, and the mean tick number, index of fecundity, engorgement weight, and egg mass weight of ticks recovered from treated animals were all significantly lower than ticks from untreated animals.

Therapeutic and persistent efficacy of a long-acting (LA) formulation of ivermectin against Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) and sera concentration through time in treated cattle.

The concentration-time profile, therapeutic, and persistent efficacy of a single subcutaneous injection of cattle with a long-acting (LA) formulation of ivermectin at a concentration of 630microg/kg of body weight were determined against Rhipicephalus (Boophilus) microplus. Ivermectin sera concentration in treated cattle increased to 13.0ppb within 1d after treatment, and peaked at 26.

Release of piperonyl butoxide and permethrin from synergized ear tags on cattle and effects on horn fly mortality.

A study was conducted to determine the release rates of piperonyl butoxide (PBO) and permethrin from synergized insecticidal cattle ear tags and their effects on mortality of the horn fly, Hematobia irritans irritans (L.) (Diptera: Muscidae). PBO was released from the ear tags at a higher rate than permethrin in both winter and summer trials.

Efficacy of a single doramectin injection against adult female Boophilus microplus (Acari: Ixodidae) in the final stages of engorgement before detachment.

The efficacy of injectable doramectin applied at 200 microg/kg was evaluated against adult female Boophilus microplus (Canestrini) (Acari: Ixodidae) in the later stages of engorgement before detachment. Lethal levels of doramectin in the serum of treated cattle (9.7-36.

Repellency of permethrin-treated battle-dress uniforms during Operation Tandem Thrust 2001.

Successful feeding by mosquitoes through permethrin-treated battle-dress uniforms (BDUs) was observed in the Shoalwater Bay Training Area (SWBTA), Queensland, Australia, during Operation Tandem Thrust 1997 (TT97). Therefore, during Operation Tandem Thrust 2001, the repellency of permethrin-treated BDUs was evaluated. Washing permethrin-treated BDUs 1 time reduced the permethrin concentration by 60%, but permethrin concentration was not reduced further after subsequent washings (up to 20 times).