Endectocide activity of a new long-action formulation containing 2.25% ivermectin+1.25% abamectin in cattle

The present work aimed to evaluate the endectocide activity of a new injectable long-action formulation, containing ivermectin (IVM) and abamectin (ABA). In each one of the four experiments performed, the following groups were formed: group I: 2.25% IVM (450 mu g/kg) + 1.25% ABA (250 mu g/kg), group II: 3.15% IVM (630 mu g/kg) and group III: control. Eighteen bovine naturally infected by gastrointestinal nematoda were selected for anthelmintic evaluation and necropsied on posttreatment day (PTD) 14 to estimate the total parasitic burden. For the Rhipicephalus (Boophilus) microplus field trial, 30 bovine were selected by means of counts of semi-engorged R. (B.) microplus and the therapeutic and residual efficacy evaluated by tick counts on PTDs 1, 3, 7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, 84 and 91. In the stall test, 15 calves were artificially infested with 5000 R. (B.) microplus (Mozzo strain) larvae three times a week and daily collections of all the engorged female ticks detached from each calf were performed until the PTD 80. Forty bovine naturally infected with Dermatobia hominis larvae were selected and the number of larvae was counted by visual and tactile inspection on PTDs 3, 7, 14, 28, 35, 49, 63, 77, 91 and 105. In this trial, a formulation containing 1% doramectin (200 mu g/kg) was also used. IVM + ABA formulation and 3.15% IVM eliminated four of the eight species of nematode identified. The anthelmintic efficacy of the avermectins association against Haemonchus placei, Cooperia spatulata and C. punctata was 89.64%, 98.84% and 97.69%, while 3.15% IVM achieved 30.98%, 84.79% and 75.56%, respectively. The two formulations evaluated showed reduced acaricide action on the PTD I and 3, reaching high efficacy percentages from PTD 14 onward. The IVM + ABA showed efficacy above 95% in the period between PTDs 21 and 49. In the stall test, it observed no difference (P > 0.05) between the two formulations regarding the R. (B.) microplus counts during the entire evaluation period. IVM + ABA reduced the number of ticks from the PTD 1 to 77 (P < 0.05) and 3.15% IVM reduced (P < 0.05) the tick number from PTD 4 up to PTD 80. The three endectocides showed no difference (P > 0.05) regarding the number of D. hominis larvae and prevented this parasite reestablishment until PTD 105. These results indicate that the IVM + ABA association showed higher anthelmintic activity and similar efficacy against arthropods to the formulation containing 3.15% IVM. (C) 2008 Elsevier B.V. All rights reserved.

Farmacocinética e eficácia endectocida de uma nova formulação contendo doramectina 3,5% em bovinos

Pós-graduação em Medicina Veterinária - FCAV

Parâmetros farmecocinéticos e atividade endectocida de uma nova formulação contendo avermectinas, via tópica (pour-on), em bovinos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Atividade endectocida, segurança clínica e farmacocinética de resíduos de uma nova alternativa terapêutica (Fluazuron + Abamectina) em bovinos

Pós-graduação em Medicina Veterinária - FCAV

Acaricidal effects of fluazuron (2.5 mg/kg) and a combination of fluazuron (1.6 mg/kg) + ivermectin (0.63 mg/kg), administered at different routes, against Rhipicephalus (Boophilus) microplus parasitizing cattle

The present study aimed to evaluate the acaricidal efficacy of fluazuron (2.5 mg/kg), administered as a pour-on, in comparison to an injectable formulation containing fluazuron (1.6 mg/kg) + ivermectin (0.63 mg/kg), against Rhipicephalus (Boophilus) microplus in naturally and experimentally infested cattle. Two studies were conducted with different tick strains, one with artificial infestations (Stall Test, using leight animals per group) and one with natural infestations (utilizing ten animals per group): In both studies, the animals were randomized, according to average tick counts performed on days -3, -2 and -1, into four groups: T01, negative control (saline solution); T02, pour-on fluazuron (2.5 mg/kg); T03: subcutaneous fluazuron (1.6 mg/kg) + ivermectin (0.63 mg/kg); and T04 subcutaneous ivermectin (0.63 mg/kg). Based on obtained results, and considering the utilized tick strains, it was possible to conclude that the pour-on fluazuron (2.5 mg/kg) formulation demonstrated high acaricidal efficacy, with protection periods ranging from 49 to 77 days against Rhipicephalus (Boophilus) microplus. On the other hand, for the injectable fluazuron (1.6 mg/kg) + ivermectin (0.63 mg/kg) formulation, it was not possible to observe elevated anti-R. (B.) microplus effect on both artificial and experimental infestation studies. Results observed for this combination were similar or inferior to those obtained by subcutaneous ivermectin (0.63 mg/kg). Future studies with this formulation containing fluazuron (1.6 mg/kg) + ivermectin (0.63 mg/kg), regarding pharmacokinetic and/or bioavailability profiles, or even studies analyzing both this active principles separately, are needed, seeking to better understand the effects of such combination against Rhipicephalus (Boophilus) microplus parasitizing cattle. (C) 2015 Elsevier Inc. All rights reserved.

A comparison of three different methodologies for evaluating Rhipicephalus (Boophilus) rnicroplus susceptibility to topical spray compounds

This study aimed to compare three different methodologies (Adult Immersion Tests, field trials with naturally infected animals, and a Stall Test using artificially infested cattle) to evaluate the efficacy of two topical formulations that we administered as whole body sprays (15% Cypermethrin + 30% Chlorpyriphos + 15% Fenthion-Colosso (R) FC 30, Ouro Fino Agronegocios; and 60% Dichlorvos + 20% Chlorpyriphos-Ectofos (R), Vallee Saude Animal Ltd.), against a susceptible strain of Rhipicephalus (Boophilus) microplus. To achieve this objective, two natural infestation trials were conducted, as well as two artificial infestation trials (Stall Tests) and two Adult Immersion Tests (AIT). The AIT results showed that both spray formulations achieved 100% efficacy against R. (B.) micro plus fully engorged females. However, when observing results obtained by field trials (natural infestations) and Stall Tests, none of these topically applied compounds reached 100% efficacy or affected the reproductive capacity of the fully engorged female ticks. Additional studies must be conducted to compare these in vivo methodologies with different in vitro techniques, such as the Larval Packet Test. However, based on results obtained here, we can conclude that depending on the spray formulations used, the AIT can overestimate acaricidal efficacy and values of reproductive efficiency of such compounds against R (B.) micro plus. Specifically, when dealing with spray formulations in the Stall Tests, the period of residual action can increase because these animals are sheltered from contact with environmental factors that might interfere with the efficacy of the products tested. It may be necessary to take in vivo trial results into consideration (such as field trials with naturally infested animals or Stall Tests) to standardize a specific in vitro assay, such as the Adult Immersion Test. (C) 2014 Elsevier B.V. All rights reserved.

Effect of a spray formulation on the reproductive parameters of a susceptible population of Rhipicephalus (Boophilus) microplus

The number of studies emphasizing the possible damage that acaricidal spray formulations can cause on engorged female ticks'reproductive parameters is small. The present study evaluated the deleterious effects of a spray formulation (dichlorvos 60% + chlorpyrifos 20%) on the reproductive parameters of a susceptible population of Rhipicephalus (B.) microplus females, using the Stall Test. The ticks were allocated randomly to treatments according to the mean numbers of females detached from each cow on days -3, -2 and -1 and the cattle pen location. The numbers of engorged female ticks that naturally detached from the cattle were counted daily from day 1 to day 30. For each group, 20 detached engorged female ticks or the available number collected daily were evaluated regarding reproductive parameters. Associations of organophosphates demonstrated elevated acaricidal efficacy, as well as deleterious effects on the reproductive parameters of R. (B.) microplus females. The engorged female weight (days 1 to 7), weight of egg masses (days 5 to 10) and larval hatching percentage (days 5 to 19) were decreased (P <= 0.05). It is possible that a formulation can lead to deleterious effects on R. (B.) microplus females when the tick population analyzed shows elevated sensitivity towards a particular formulation. However, further studies need to be conducted.

Questionnaire-based study to assess the association between management practices and mastitis within tie-stall and free-stall dairy housing systems in Switzerland.

BACKGROUND Prophylactic measures are key components of dairy herd mastitis control programs, but some are only relevant in specific housing systems. To assess the association between management practices and mastitis incidence, data collected in 2011 by a survey among 979 randomly selected Swiss dairy farms, and information from the regular test day recordings from 680 of these farms was analyzed. RESULTS The median incidence of farmer-reported clinical mastitis (ICM) was 11.6 (mean 14.7) cases per 100 cows per year. The median annual proportion of milk samples with a composite somatic cell count (PSCC) above 200,000 cells/ml was 16.1 (mean 17.3) %. A multivariable negative binomial regression model was fitted for each of the mastitis indicators for farms with tie-stall and free-stall housing systems separately to study the effect of other (than housing system) management practices on the ICM and PSCC events (above 200,000 cells/ml). The results differed substantially by housing system and outcome. In tie-stall systems, clinical mastitis incidence was mainly affected by region (mountainous production zone; incidence rate ratio (IRR) = 0.73), the dairy herd replacement system (1.27) and farmers age (0.81). The proportion of high SCC was mainly associated with dry cow udder controls (IRR = 0.67), clean bedding material at calving (IRR = 1.72), using total merit values to select bulls (IRR = 1.57) and body condition scoring (IRR = 0.74). In free-stall systems, the IRR for clinical mastitis was mainly associated with stall climate/temperature (IRR = 1.65), comfort mats as resting surface (IRR = 0.75) and when no feed analysis was carried out (IRR = 1.18). The proportion of high SSC was only associated with hand and arm cleaning after calving (IRR = 0.81) and beef producing value to select bulls (IRR = 0.66). CONCLUSIONS There were substantial differences in identified risk factors in the four models. Some of the factors were in agreement with the reported literature while others were not. This highlights the multifactorial nature of the disease and the differences in the risks for both mastitis manifestations. Attempting to understand these multifactorial associations for mastitis within larger management groups continues to play an important role in mastitis control programs.

A Novel Range Test

In a range test, one party holds a ciphertext and needs to test whether the message encrypted in the ciphertext is within a certain interval range. In this paper, a range test protocol is proposed, where the party holding the ciphertext asks another party holding the private key of the encryption algorithm to help him. These two parties run the protocol to implement the test. The test returns TRUE if and only if the encrypted message is within the certain interval range. If the two parties do not conspire, no information about the encrypted message is revealed from the test except what can be deduced from the test result. Advantages of the new protocol over the existing related techniques are that it achieves correctness, soundness, °exibility, high e±ciency and privacy simultaneously.