Oral and Poster Abstracts

Results: On D0, the animals included in both experiments showed
no statistical difference in their initial body weight and weight gains.
On D90 in the Exp.1, animals treated with the combination of 2.25%
ivermectin + 1.25%abamectin showed higher gain in body weight
than those treated with moxidectin (35.6kg vs. 31.3kg). Similarly, on
D100 in the Exp.2, in the animals treated with 2.25% ivermectin +
1.25% abamectin the weight gain was higher on average by 7.45kg
than in animals treated with 10% moxidectin. In the same
experiment on D100 no statistically significant difference was found
in the weight gains between the group medicated with moxidectin
and the non medicated control group.
Conclusions: Treatment of pasture-kept Nelore calves with a
combination of 2.25% ivermectin and 1.25% moxidectin proved to
have positive effect on the body weight gain of medicated animals as
compared to a non treated control group. Moreover this positive
effect was statistically higher than the effect of 10% moxidectin
(p>0.05).
1184 Comparative Evaluation of Anthelmintic Action of Different
Long Acting Avermectins in Calves and Their Effect on
Body Weight
W. Lopes 1 , C. Buzzulini 1 , R. Mendonca 1 , C. Sakamoto 1 , R. Lima 1 ,
T. Arantes 2 , 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 evaluate the efficacy of
three long acting formulations containing 2.25% ivermectin + 1.25%
abamectin (Solution 3,5%, LA, Intervet), 3.15% ivermectin (Ivomec ®
Gold, Merial) and 3.5% ivermectin (Megamectin, 3.5%, Novartis) in
the control of gastrointestinal nematodes and the effect of the treatment
on the weight gain in calves.
Materials and Methods: The study was performed as two separate
experiments with 104 calves. The animals used in the study showed
no difference in respect to the parasite load (Exp. 1) and body weight
(Exp. 2). Exp.1: On Day 0 the animals (n=24, 6 per group) were
treated with either of the three long acting formulations: 2.25%
ivermectin+1.25% abamectin (Solution 3,5%, LA, Intervet), 3.15%
ivermectin (Ivomec, Gold, Merial) or 3.5% ivermectin (Megamectin,
3.5%, Novartis) administered subcutaneously according to
producers recommendations. On D14 post treatment all calves were
euthanized and necropsy was performed to assess the parasites load.
Exp. 2: In order to monitor the changes in the weight gain in treated
animals all calves (n=20) were individually weighted on D-30, D0
and D60. On D0 the animals were treated as in the Exp. 2. In each
evaluation period weight gain was recorded for each individual
animal.
Results: In the Exp. 1 the following nematode species were identified:
H. placei, C. punctata, C. spatulata, C. pectinata, O. radiatum and T.
discolor. The treatment with 2.25% ivermectin+1.25% abamectin
showed higher anthelmintic efficacy than the remaining two
formulations. Evaluation of body weight gains in Exp. 2 demonstrated
the overall weight gain differences of 10.0kg, 14.5kg and 21.15kg for
3.15% ivermectin, 3.5% ivermectin and 2.25%ivermectin+1.25%
abamectin combination above the control group, respectively.
Conclusions: Long acting formulation containing 2.25% ivermectin
and 1.25% abamectin was demonstrated to have higher anthelmintic
efficacy than 3.15% ivermectin or 3.5% ivermectin and lead to
higher weight gain in treated calves. All treatments groups showed
significant weight gain in comparison to non treated control animals.
1185 Anthelmintic Activity and Effect on Body Weight of a 2.25%
Ivermectin + 1.25% Abamectin Combination in Comparison
to other Endectocides in Calves
R. Mendonca 1 , C. Sakamoto 1 , R. Lima 1 , W. Lopes 1 , C. Buzzulini 1 ,
H. Silva 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 compare the
anthelmintic efficacy and effect on body weight of a formulation
containing 2.25 %ivermectin + 1.25% abamectin and other
endectocides in cattle.
286 XXV. Jubilee World Buiatrics Congress 2008
Materials and Methods: The study was conducted in Brazil as two
experiments with a total number of 84 calves naturally infected with
gastrointestinal parasites. In the Exp. 1, the animals (n=24, 6 per
group) were treated with three long acting formulations: 2.25%
ivermectin + 1.25% abamectin (Solution 3.5% LA, Intervet), 3.15%
ivermectin (Ivomec, Gold, Merial) and 3.5% ivermectin
(Megamectin 3.5%, Novartis) according to the producers
recommendations. On D14 post treatment all the calves were
euthanized and the parasitic load was assessed at necropsy. In the
Exp. 2, the animals (n=60, 15 per group) were administered either
with 2.25% ivermectin + 1.25% abamectin (Solution 3.5% LA,
Intervet) or 1% moxidectin (Cydectin 1%, Fort Dodge) or 1%
doramectin (Dectomax 1%, Pfizer). Individual body weight
measures were conducted for all animals on D-30, D0 (treatment
day), D60 and D120 in respect to the time of treatment.
Results: In the Exp. 1 no statistically significant difference was
found between the calves treated with three tested products in
respect to the presence of: H. similis, C. pectinata, T. axei, T.
colubribormis, O. radiatum, O. ostertagii and O. lyrata. The
formulation containing 2.25% ivermectin + 1.25% abamectin was
however statistically more effective than the other two products
against H. placei and C. punctata, the two most prevalent species in
Brazil. In the Exp.2 calves treated with the product containing 2.25%
ivermectin + 1.25% abamectin showed statistically significant
advantage as compared to the animals that received 1% moxidectin
(weight gain difference 12.4kg) and 1% doramectin (weight gain
difference 12.54kg).
Conclusions: The results of the study indicated that formulation of
2.25% ivermectin + 1.25% abamectin showed significantly higher
activity against H. placei and C. punctata than 3.15% or 3.5%
ivermectin. Moreover medication with the first formulation resulted in
superior gains in body weight as compared to 1% moxidectin or 1%
doramectin.
1186 Efficacy of an Avermectin Association against
Gastrointestinal Helminths Resistant to Ivermectin and
Doramectin in Cattle
V. Rangel 1 , R. Leite 1 , G. Almada 2 , T. Arantes 3 , J. Costa 1 ,
E. Santos 4 , P. Oliveira 1
1 UFMG, Dept. Escola de Veterinária, Belo Horizonte, Brazil
2 UVV, Dept. Bioagrárias, Vila Velha, Brazil
3 Intervet Schering-Plough, Desenvovimento, Sâo Paulo, Brazil
4 Intervet Schering-Plough, Int. Marketing, Boxmeer, Netherlands
Introduction: Anthelmintic resistance is becoming a serious
problem in cattle world wide, especially in countries like Brazil. The
aim of this study was to assess the efficacy of an avermectin
association against gastrointestinal helminths resistant to ivermectin
and doramectin.
Materials and Methods: The study was conducted in Brazil on a
beef cattle farm with reported lack of efficacy for ivermectin and
doramectin. Fecal egg reduction test confirmed low efficacy of these
substances, but not of abamectin. Egg samples were used to produce
larvae for controlled infection. Calves (n=54) were infected with
larvae of H. placei, C. punctata and O. radiatum (dose: 11.000,
11.000 and 48.000 larvae respectively). After 46 days, 48 calves
were selected and evenly distributed into 8 groups. Four treatments
were used, 2 groups per treatment: T1 - Control group, untreated, T2
- doramectin 1% (Dectomax, Pfizer), T3 - ivermectin 3,15%
(Ivomec, Gold, Merial) and T4 - ivermectin 2.25% + abamectin
1.25% (Solution 3.5% LA, Intervet). The products were
administered according to the manufacturers recommendations.
Necropsies were conducted to determine the efficacy of the
treatments. In order to evaluate the persistence of efficacy, 4
experimental groups were evaluated at 14d and other 4 groups at 28d
after treatment. The study was carried out according to the
recommendations of the World Association for the Advancement of
Veterinary Parasitology (WAAVP).
Results: The efficacy of the treatments at 14d post administration
and calculated as geometric mean was T2: 73%, 74% and 0%; T3:
24%, 37% and 0%; and T4: 67%, 96% and 86%, against H. placei, C.
punctata and O. radiatum, respectively. The 28d efficacy was T2:
38%, 79% and 16%; T3: 44%, 65% and 0%; and T4: 90%, 97% and
94%, against H. placei, C. punctata and O. radiatum, respectively.
Conclusions: The results demonstrated that strains of H. placei, C.
punctata and O. radiatum resistant to ivermectin and doramectin