Oral and Poster Abstracts

T. Arantes 2 , C. Buzzulini 1 , W. Lopes 1 , R. Mendonca 1 ,
C. Sakamoto 1 , R. Lima 1 , G. Oliverira 1 , A. Costa 1
1 CPPAR/FCAV/UNESP, Animal Health Research Center,
Jaboticabal, Brazil
2 Intervet Schering-Plough, Desenvovimento, Sâo Paulo, Brazil
Introduction: The aim of this study was to determine the efficacy of a
pour on formulation containing 12% chlorpyrifos base against flies and
ticks in naturally infested cattle.
Materials and Methods: The study was carried out as four
experiments. In the Exp. 1, 2 and 3, focusing on the activity against
Haematobia irritans, 45 naturally infested animals were selected on
the basis of the entire body hornfly count performed on D-2 and D-1
in respect to the treatment day. The animals were treated with a 12%
chlorpyrifos base pour on formulation (Expert, pour-on, Intervet) or
12.5% diazinon (Neocidol, pour-on, Novartis) according to the
producers recommendations. In each treated animal the fly count
was performed on D3, D7 and subsequently on weekly interval post
treatment until no therapeutic effect of the products was observed. In
the Exp. 4, focusing on the activity against Ripicephalus (Boophilus)
microplus, 30 animals of Holstein-Zebu cross were selected on the
basis of three consecutive counts of female R. microplus (5.4-8.0mm
in length) present on the left side of the animal, performed on D-3,
D-2 and D-3 in respect to the treatment day. The animals were
treated with a 12% chlorpyrifos base pour on formulation (Expert,
pour-on, Intervet) or 1% fipronil (Topline, pour-on, Merial)
according to the producers recommendations. The post-treatment
tick count was carried out on D1, D3, D7 and subsequently on
weekly basis until D35 post treatment.
Results: Formulation containing 12% chlorpyrifos base showed
higher efficacy against H. irritans than 12.5% diazinon, reaching
100% efficacy on D3 post administration. The duration of activity
against R. microplus of 12% chlorpyrifos pour on proved to be
shorter than of 1% fipronil, however no difference in the efficacy for
these two products was demonstrated until D14 post treatment. The
efficacy of 12% chlorpyrifos against ticks was above 95% between
D7 and D21 post administration.
Conclusions: The results of this study indicated high efficacy of a pour
on formulation containing 12% chlorpyrifos base against H. irritans
flies and R. microplus ticks in naturally infested cattle.
1181 Efficacy of 50%Chlorpyrifos + 50%Amitraz Combination
against R. microplus in Experimentally and Naturally
Infected Cattle
C. Buzzulini 1 , R. Mendonca 1 , C. Sakamoto 1 , R. Lima 1 ,
W. Lopes 1 , W. Garcia 1 , G. Oliverira 1 , T. Arantes 2 , A. Costa 1
1 CPPAR/FCAV/UNESP, Animal Health Research Center,
Jaboticabal, Brazil
2 Intervet Schering-Plough, Desenvovimento, Sâo Paulo, Brazil
Introduction: The aim of this study was to evaluate the efficacy of a
formulation containing 50% chlorpyrifos + 50% amitraz against ticks
Ripicephalus (Boophilus) microplus in experimentally and naturally
infected cattle.
Materials and Methods: The study was conducted as two separate
experiments. In the Experiment 1, after the acclimatization period,
the animals (n=10) were infected with 5,000 larvae of R. microplus,
aged 14-21 days. The animals were then divided into two
experimental groups (n=5, each) on the basis of the number of
female parasites collected on D-3, -2 and -1 in respect to the
treatment date. The animals were then treated with a combination of
50% chlorpyrifos+50% amitraz (Amiphós, Intervet) according to
producer’s recommendations. In the Experiment 2, twenty animals
of Holstein breed naturally infected with the R. microplus ticks were
divided into two groups using the count of R. microplus females
(4.5-8.0mm in length) present on the left side of the animal on D -3,
D-2 and D-1 in respect to the treatment date. Animals in Exp. 2 were
treated similarly to those in Exp.1. The efficacy was measured
through the assessment of the average number of R. microplus on the
animals in treated and control group according to procedure
standardized by World Association for the Advancement of
Veterinary Parasitology (WAAVP).
Results: In the Exp.1 efficacy above 90% was demonstrated for the
tested formulation between D3 and D35 post treatment. At each check
time point until D35 the efficacy of the product proved to be above
95%. The efficacy rapidly decreased as from D35 (