RESUMO
Biomarkers are specific molecular, histological, or physiological characteristics of normal or pathogenic biological processes and are promising in the diagnosis of gastrointestinal nematodes (GINs). Although some biomarkers have been validated for infection by Ostertagia sp. in cattle raised in temperate regions, there is a lack of information for tropical regions. The aim of this project was to assess potential biomarkers and validate the most promising. In the first study, 36 bovines (Nelore breed) naturally infected by GINs were distributed into two groups: infected (not treated with anthelmintic) and treated (treated with fenbendazole on days 0, 7, 14, 21, 28, 42, and 56). The variables of interest were live weight, fecal egg count, hemogram, serum biochemical markers, phosphorus, gastrin, and pepsinogen. In the second step, pepsinogen was assessed in cattle of the Nelore breed distributed among three groups: infected (not treated with anthelmintic), MOX (treated with moxidectin), and IVM + BZD (treated with ivermectin + albendazole). In the first study, no difference between groups was found for weight, albumin, hematocrit (corpuscular volume [CV]), erythrocytes, or hemoglobin. Negative correlations were found between pepsinogen and both CV and albumin, and albumin was negatively correlated with the percentage of Haemonchus sp. in the fecal culture. Among the biomarkers, only pepsinogen differentiated treated and infected (beginning with the 28th day of the study). In the second study, a reduction in pepsinogen was found after anthelmintic treatment. Therefore, pepsinogen is a promising biomarker of worms in cattle naturally infected by the genera Haemonchus and Cooperia in tropical areas.
Assuntos
Biomarcadores , Doenças dos Bovinos , Fezes , Infecções por Nematoides , Clima Tropical , Animais , Bovinos , Doenças dos Bovinos/parasitologia , Doenças dos Bovinos/tratamento farmacológico , Biomarcadores/sangue , Infecções por Nematoides/veterinária , Infecções por Nematoides/parasitologia , Infecções por Nematoides/tratamento farmacológico , Fezes/parasitologia , Contagem de Ovos de Parasitas , Anti-Helmínticos/uso terapêutico , Nematoides/isolamento & purificação , Nematoides/classificação , Nematoides/efeitos dos fármacos , Gastroenteropatias/parasitologia , Gastroenteropatias/veterinária , Enteropatias Parasitárias/veterinária , Enteropatias Parasitárias/parasitologia , Fenbendazol/uso terapêuticoRESUMO
BACKGROUND: The occurrence of higher winter temperatures in Brazilian areas with tropical and highland climates may result in a fifth peak of tick populations during winter in addition to the four generations previously described. Therefore, a strategic control protocol was developed with treatments in two seasons with the objective of controlling the generations of ticks that occur in spring/summer and those that occur in autumn/winter. METHODS: The study was conducted in Mato Grosso do Sul, Brazil, from the beginning of the rainy season, November 2020, to October 2021. In a randomized block design, 36 calves were distributed into three groups: (i) negative control; (ii) traditional strategic control in one season (SC1S), at the beginning of the rainy season; and (iii) strategic control in two seasons (SC2S), at the beginning and end of the rainy season. The SC1S strategic control group was treated on day 0, November 2020, and twice more with intervals of 42 days. The SC2S group received three more treatments beginning on day 182, May 2021, with intervals of 42 days. All treatments consisted of 5% fluralaner (Exzolt® 5%) delivered via a pour-on dose of 1 mL/20 kg body weight. Counts of semi-engorged female ticks were performed on day 3 and every 14 days thereafter, and the animals were weighed at the same time. RESULTS: Fluralaner showed a mean efficacy of more than 95% up to day 294. The two treated groups showed a decrease (P < 0.05) in the average number of ticks on day 3. In the SC2S group, the means were close or equal to zero throughout the study, while in the SC1S group, the means did not differ (P > 0.05) from those of the control group from day 231 onward. The final mean weight gain of each group was 76.40 kg, 98.63 kg, and 115.38 kg for the control, SC1S, and SC2S groups, respectively, differing (P < 0.05) from each other. CONCLUSIONS: Therefore, three applications of fluralaner, with one application every 42 days from the beginning of the rainy season in the middle spring, resulted in effective tick control for 224 days. When three additional treatments were given in autumn/winter with intervals of 42 days between applications, tick counts were reduced throughout the year. This strategic control approach may be indicated in years with climatic conditions that allow that population peaks are expected to occur in the autumn/winter period.
Assuntos
Rhipicephalus , Feminino , Bovinos , Animais , Isoxazóis/farmacologia , Brasil , ChuvaRESUMO
A possible synergistic effect of macrocyclic lactones' (MLs) combination has been previously described against resistant gastrointestinal nematodes of cattle. In addition to synergism, drug-drug interactions between MLs can also result in additive or antagonistic effect, considering the different MLs pharmacokinetics, pharmacodynamics, and interactions with molecular mechanisms of resistance. Therefore, the aim of the current work was evaluated the effect of different MLs combinations against Haemonchus contortus. Infecting larvae of two isolates (one susceptible and one resistant to ivermectin) were used in the larval migration inhibition test. After estimating the half maximal effective concentration of abamectin (ABA), eprinomectin, (EPR), ivermectin (IVM), and moxidectin (MOX) for both isolates, combinations were delineated by a simplex-centroid mixture experiment, and the mixture regression analysis was applied to the special cubic model. A synergistic effect was found for the EPR + MOX against the susceptible isolate as well as the EPR + MOX, IVM + MOX, and ABA + EPR + IVM against the resistant isolate. An antagonistic effect of ABA + IVM + MOX was found against the susceptible isolate. For the susceptible isolate, a higher inhibition was found with greater proportions of EPR and lower proportions of the other drugs compared to the reference mixture. For the resistant isolate, inhibition greater than that of the reference mixture was found with higher proportions of IVM as well as lower proportions of the other drugs. The synergistic and antagonistic effects were dependent on the following: (a) parasite drug resistance profile, (b) the composition of the combination, and (c) the proportions used, with EPR and IVM exerting a greater impact on these effects.
Assuntos
Anti-Helmínticos , Haemonchus , Animais , Bovinos , Ivermectina/farmacologia , Lactonas/farmacologia , Interações Medicamentosas , Resistência a Medicamentos , Anti-Helmínticos/farmacologia , Anti-Helmínticos/uso terapêuticoRESUMO
Studies on the rearing of ewe lambs in the Cerrado are scarce, so the objective was to evaluate the effects of protein-energy supplementation with 1.6 and 2.4% BW on the productive and reproductive performance of ewe lambs raised on pastures of Brachiaria brizantha cv. Marandu. Twenty-four Texel ewe lambs, with a mean age of 5 months, were distributed in two treatments with provision of energy protein supplementation at levels of 1.6 and 2.4% BW, formulated for average daily gains of 150 and 200 g/day for ewe lambs weighing 20 kg, respectively. The experimental delineation adopted was the completely randomized design, with fifteen repetitions per treatment. The performance of the ewe lambs was evaluated by weight at the beginning and end of the breeding season (BS), average daily gain (ADG), and total weight gain (TWG). The count of fecal eggs was performed monthly. The evaluation of the ewe lambs reproductive organs took place at 8 months of age. The fertility of the ewe lambs was detected by transrectal ultrasonography at the end of the BS. The supplementation level of 2.4% BW was higher for ADG and TWG; however, it did not influence the other performance characteristics. There was no effect of supplementation on the reproductive characteristics, parasite load, and nutrients of the pasture. Pasture nutrients were influenced by the month of use. Supplementation levels were not effective to ensure the reproductive success of 8-month-old ewe lambs.
Assuntos
Óvulo , Melhoramento Vegetal , Animais , Suplementos Nutricionais , Feminino , Reprodução , Ovinos , Carneiro DomésticoRESUMO
Southern cattle tick resistance to pour-on and injectable acaricides has yet to be evaluated on a broader scope, and the paucity of information on the subject may hinder efforts to control this parasite. The objective of this study was to evaluate the resistance profile of ten populations of Rhipicephalus microplus to the acaricides fluazuron, fipronil and ivermectin in cattle herds in Mato Grosso do Sul, Brazil. The larval immersion test (LIT) was used to evaluate susceptibility to ivermectin and fipronil and the adult immersion test (AIT) was performed to evaluate fluazuron. Samples were randomly obtained in ten farms, and in general, we found resistance in five samples to fluazuron and in four samples to ivermectin and fipronil. Six samples showed incipient resistance to ivermectin and fipronil. Five of the ten evaluated samples showed resistance and/or incipient resistance to all the active ingredients, and the other five to two active ingredients. Among the samples classified as resistant, the average resistance ratio for ivermectin was 2.75 and 3.26 for fipronil. These results demonstrate the advanced status of resistance to the most modern chemical groups for the control of R. microplus in the state of Mato Grosso do Sul.
Assuntos
Acaricidas , Doenças dos Bovinos , Resistência a Medicamentos , Rhipicephalus , Infestações por Carrapato , Acaricidas/farmacologia , Animais , Brasil , Bovinos , Doenças dos Bovinos/parasitologia , Ivermectina/farmacologia , Compostos de Fenilureia/farmacologia , Pirazóis/farmacologia , Rhipicephalus/efeitos dos fármacos , Infestações por Carrapato/parasitologia , Infestações por Carrapato/veterináriaRESUMO
The objective of this study was to evaluate the therapeutic efficacy of 1 % injectable doramectin to control Dermatobia hominis in naturally infested beef cattle in a farm with history of clinical parasitism after avermectin use. The study was conducted in a commercial beef cattle farm in Brazil. Twenty crossbred cattle (Nellore x Angus) were selected based on the minimum number of 10 live larvae. Assessment of infestation was performed based on tactile-visual inspection of the entire body of the animals. The animals were allocated to two experimental groups of ten animals each: treated group - dosed with doramectin 200⯵g/kg live weight (LW), and control group - dosed with saline solution 1â¯mL/50â¯kg LW. Both treatments were administered subcutaneously in a single dose. After treatment, larval counts were performed at 1, 3, 7 and 14 days post-treatment (DPT). For the treatment to be considered efficient, it should reach an efficacy greater than or equal to 90 % by the 10th DPT and the average larval count in the treated animals should be statistically lower than the average larval count in the control group. The geometric means of larval counts at the beginning of the study were 27.2 and 26.3 for the control and treated groups, respectively. After 72â¯h of treatment, there was a significant reduction (pâ¯<â¯0.01) in the larvae counts of the treated group, extending to the 14th DPT, at which point maximum efficacy for doramectin (86.3 %) was obtained. After treatment, 90 % of the animals remained parasitized with live larvae on the 7th DPT and 70 % on the 14th DPT, while in the control group, all animals were infested on all dates. The administration of injectable doramectin was not effective in controlling D. hominis in naturally infested cattle.
Assuntos
Doenças dos Bovinos/parasitologia , Dípteros/efeitos dos fármacos , Inseticidas/farmacologia , Ivermectina/análogos & derivados , Miíase/veterinária , Animais , Bovinos , Resistência a Inseticidas , Ivermectina/farmacologia , Miíase/parasitologiaRESUMO
Southern cattle tick resistance to pour-on and injectable acaricides has yet to be evaluated on a broader scope, and the paucity of information on the subject may hinder efforts to control this parasite. The objective of this study was to evaluate the resistance profile of ten populations of Rhipicephalus microplus to the acaricides fluazuron, fipronil and ivermectin in cattle herds in Mato Grosso do Sul, Brazil. The larval immersion test (LIT) was used to evaluate susceptibility to ivermectin and fipronil and the adult immersion test (AIT) was performed to evaluate fluazuron. Samples were randomly obtained in ten farms, and in general, we found resistance in five samples to fluazuron and in four samples to ivermectin and fipronil. Six samples showed incipient resistance to ivermectin and fipronil. Five of the ten evaluated samples showed resistance and/or incipient resistance to all the active ingredients, and the other five to two active ingredients. Among the samples classified as resistant, the average resistance ratio for ivermectin was 2.75 and 3.26 for fipronil. These results demonstrate the advanced status of resistance to the most modern chemical groups for the control of R. microplus in the state of Mato Grosso do Sul.(AU)
A resistência do carrapato-do-boi a acaricidas com modo de aplicação "pour-on" e injetáveis é pouco avaliada em estudos mais abrangentes, e essa escassez de informação pode resultar falhas no seu controle. Este estudo teve como objetivo avaliar o perfil de resistência em dez populações de Rhipicephalus microplus aos acaricidas fluazuron, fipronil e ivermectina, em rebanhos bovinos em Mato Grosso do Sul, Brasil. A caracterização fenotípica da resistência foi realizada por meio do teste de imersão de adultos (AIT) para o fluazuron, e teste de imersão de larvas (LIT) para fipronil e ivermectina. As amostras foram obtidas aleatoriamente em dez fazendas, sendo diagnosticada resistência em cinco amostras ao fluazuron e em quatro amostras à ivermectina e fipronil. Seis amostras apresentaram resistência incipiente à ivermectina e fipronil. Cinco das dez amostras avaliadas apresentaram resistência e / ou resistência incipiente a todos os princípios ativos, e as outras cinco a dois princípios ativos. Entre as amostras classificadas como resistentes, a média do fator de resistência para ivermectina foi de 2,75 e de 3,26 para fipronil. Esses resultados demonstram o avançado estado de resistência aos mais modernos grupos químicos para o controle de R. microplus em Mato Grosso do Sul.(AU)
Assuntos
Rhipicephalus/imunologia , Rhipicephalus/parasitologia , Ivermectina/efeitos adversos , Ivermectina/análise , Acaricidas/imunologiaRESUMO
Plant extracts are a potential source of new compounds for nematode control and may be an excellent alternative for the control gastrointestinal nematodes that are resistant to conventional anthelmintics. However, research involving natural products is a complex process. The main challenge is the identification of bioactive compounds. Online analytical techniques with universal detectors, such as high-performance liquid chromatography-mass spectrometry (HPLC-MS), together with metabolomics could enable the fast, accurate evaluation of a massive amount of data, constituting a viable option for the identification of active compounds in plant extracts. This study focused on the evaluation of the ovicidal activity of ethanol extracts from 17 plants collected from the Pantanal wetland in the state of Mato Grosso do Sul, Brazil, against eggs of Haemonchus placei using the egg hatchability test. The ethanol extracts were obtained using accelerated solvent extraction. The data on ovicidal activity, mass spectrometry and metabolomics were evaluated using HPLC-DAD-MS, partial least squares regression analysis (PLS-DA) and a correlation map (univariate correlation analyses) to detect compounds that have a positive correlation with biological activity. Among the ten metabolites with the best correlation coefficients, six were phenylpropanoids, two were triterpene saponins, one was a brevipolide, and one was a flavonoid. Combinations of metabolites with high ovicidal action were also identified, such as phenylpropanoids combined with the triterpene saponins and the flavonoid, flavonoids combined with iridoid and phenylpropanoids, and saponins combined with phenylpropanoid. The positive correlation between classes of compounds in plants belonging to different genera and biological activity (as previously identified in the literature) reinforces the robustness of the statistical data and demonstrates the efficacy of this method for the selection of bioactive compounds without the need for isolation and reevaluation. The proposed method also enables the determination of synergism among the classes, which would be impracticable using traditional methods. The present investigation demonstrates that the metabolomic technique was efficient at detecting secondary metabolites with ovicidal activity against H. placei. Thus, the use of metabolomics can be a tool to accelerate and simplify bioprospecting research with plant extracts in veterinary parasitology.
Assuntos
Antinematódeos/análise , Etanol/análise , Metabolômica/métodos , Plantas/química , Animais , Antinematódeos/farmacologia , Brasil , Cromatografia Líquida de Alta Pressão , Etanol/farmacologia , Flavonoides/análise , Flavonoides/farmacologia , Haemonchus/efeitos dos fármacos , Espectrometria de Massas , Compostos Fitoquímicos/análise , Compostos Fitoquímicos/farmacologiaRESUMO
Babesiosis is a tick-borne hemolytic disease caused by intraerythrocytic protozoan parasites of the genus Babesia. The present study describes epidemiological, clinical, and pathological features of cases of bovine babesiosis diagnosed over the last two decades in the state of Mato Grosso do Sul in central-western Brazil. Examination of a total of 5298 bovine samples resulted in a definitive or presumptive diagnosis of babesiosis in 41 cases from 33 outbreaks. Babesia bovis was the most common causal agent of bovine babesiosis, and animals of all ages were affected. Zebu cattle, which are more frequent in the study region than are taurine cattle, were the cattle most often affected. Although zebu cattle have been claimed to be highly tolerant, the present findings show that they can develop severe illness and die due to Babesia spp. infection. The disease was diagnosed almost every year over the time period covered in this study (1995-2017). However, the number of cases of bovine babesiosis diagnosed was low compared to the total number of cases reviewed. Veterinary practitioners that work on cattle farms should to be able to diagnose the disease in its early stages so that treatment can be initiated promptly and economic losses can be minimized.
Assuntos
Babesia bovis/fisiologia , Babesiose/epidemiologia , Doenças dos Bovinos/epidemiologia , Surtos de Doenças/veterinária , Animais , Babesiose/parasitologia , Brasil/epidemiologia , Bovinos , Doenças dos Bovinos/parasitologia , Estudos RetrospectivosRESUMO
This study aimed to analyze economically different control protocols for beef cattle gastrointestinal nematodes in Brazil. Field study data previously published was used to compare three groups: 1) non-dosed; 2) current deworming program with two doses - May and November; and 3) alternative strategic control program with three doses - May, August, and November. An economic sensitivity analysis was performed based on beef carcass price (BCP) variation, thus creating three economic scenarios: 1) more probable (M) using the mean BCP in the studied region; 2) optimistic (O) using the mean BCP plus standard deviation; and 3) pessimistic (P) using the mean BCP minus standard deviation. Stock valuation (SV), operational result (OP), and treatment differential (TD) were calculated for each scenario. Average BCP was US$ 2.93 kg-1 carcass (± US$ 0.27 kg-1 carcass). The mean annual cost of deworming per animal was US$ 5.43 and US$ 7.97 for protocols with two and three doses, respectively. The cost of anthelmintic treatment represented 0.63% and 0.74% of operating results, both in M scenario. TD ranged from 9.5% to 27.6% for the assessed protocols. Regardless of the scenario, the protocol with three annual dosages presented the highest SV and OP, which economically justifies its implementation in strategic control of gastrointestinal nematodes in grazing beef cattle in Central Brazil. These results also demonstrate the relevance of strategic anthelmintic treatments in weaned stocker calves in tropical and humid subtropical areas.
O objetivo deste estudo foi analisar diferentes protocolos de controle de nematodas gastrointestinais em bovinos de corte no Brasil. Dados de estudo de campo publicados anteriormente foram utilizados para comparar três grupos: 1) não dosificado; 2) o programa de desverminação utilizado atualmente com duas dosificações - maio e novembro; e 3) um programa de controle estratégico com três dosificações - maio, agosto e novembro. A análise de sensibilidade econômica foi realizada com base na variação do Preço da Carcaça Bovina (PCB), assim criando três cenários econômicos: mais provável (M), utilizando o PCB médio na região do estudo; Otimista (O), usando o PCB mais o desvio padrão e pessimista (P), usando o PCB menos o desvio padrão. Para cada cenário, a valorização de estoque (VE), o resultado operacional (OP) e o diferencial de tratamento (DT) foram calculados. O PCB médio foi de US$ 2.93 kg-1 de carcaça (± US$ 0.27 kg-1 de carcaça). O custo médio anual de desverminação por animal foi US$ 5.43 e US$ 7.97 no protocolo com duas e três doses, respectivamente, e o custo do anti-helmíntico representou 0.63% e 0.74% do resultado operacional, ambos no cenário M. Os diferenciais de tratamento dos protocolos avaliados variaram de 9.5% a 27.6%. Independentemente do cenário econômico simulado, o protocolo com três dosagens anuais apresentou a maior VE e OP entre os protocolos avaliados, justificando economicamente sua implementação para o controle estratégico de nematodas gastrointestinais de bovinos de corte criados em pastagem no Brasil Central e também demonstram a relevância de tratamentos anti-helmínticos estratégicos em bezerros desmamados em áreas subtropicais tropicais e úmidas.
Assuntos
Animais , Bovinos , Anti-Helmínticos/administração & dosagem , Anti-Helmínticos/economia , Criação de Animais Domésticos/economia , Gastroenteropatias/parasitologia , Gastroenteropatias/veterinária , Nematoides/efeitos dos fármacosRESUMO
This study aimed to analyze economically different control protocols for beef cattle gastrointestinal nematodes in Brazil. Field study data previously published was used to compare three groups: 1) non-dosed; 2) current deworming program with two doses - May and November; and 3) alternative strategic control program with three doses - May, August, and November. An economic sensitivity analysis was performed based on beef carcass price (BCP) variation, thus creating three economic scenarios: 1) more probable (M) using the mean BCP in the studied region; 2) optimistic (O) using the mean BCP plus standard deviation; and 3) pessimistic (P) using the mean BCP minus standard deviation. Stock valuation (SV), operational result (OP), and treatment differential (TD) were calculated for each scenario. Average BCP was US$ 2.93 kg-1 carcass (± US$ 0.27 kg-1 carcass). The mean annual cost of deworming per animal was US$ 5.43 and US$ 7.97 for protocols with two and three doses, respectively. The cost of anthelmintic treatment represented 0.63% and 0.74% of operating results, both in M scenario. TD ranged from 9.5% to 27.6% for the assessed protocols. Regardless of the scenario, the protocol with three annual dosages presented the highest SV and OP, which economically justifies its implementation in strategic control of gastrointestinal nematodes in grazing beef cattle in Central Brazil. These results also demonstrate the relevance of strategic anthelmintic treatments in weaned stocker calves in tropical and humid subtropical areas.(AU)
O objetivo deste estudo foi analisar diferentes protocolos de controle de nematodas gastrointestinais em bovinos de corte no Brasil. Dados de estudo de campo publicados anteriormente foram utilizados para comparar três grupos: 1) não dosificado; 2) o programa de desverminação utilizado atualmente com duas dosificações - maio e novembro; e 3) um programa de controle estratégico com três dosificações - maio, agosto e novembro. A análise de sensibilidade econômica foi realizada com base na variação do Preço da Carcaça Bovina (PCB), assim criando três cenários econômicos: mais provável (M), utilizando o PCB médio na região do estudo; Otimista (O), usando o PCB mais o desvio padrão e pessimista (P), usando o PCB menos o desvio padrão. Para cada cenário, a valorização de estoque (VE), o resultado operacional (OP) e o diferencial de tratamento (DT) foram calculados. O PCB médio foi de US$ 2.93 kg-1 de carcaça (± US$ 0.27 kg-1 de carcaça). O custo médio anual de desverminação por animal foi US$ 5.43 e US$ 7.97 no protocolo com duas e três doses, respectivamente, e o custo do anti-helmíntico representou 0.63% e 0.74% do resultado operacional, ambos no cenário M. Os diferenciais de tratamento dos protocolos avaliados variaram de 9.5% a 27.6%. Independentemente do cenário econômico simulado, o protocolo com três dosagens anuais apresentou a maior VE e OP entre os protocolos avaliados, justificando economicamente sua implementação para o controle estratégico de nematodas gastrointestinais de bovinos de corte criados em pastagem no Brasil Central e também demonstram a relevância de tratamentos anti-helmínticos estratégicos em bezerros desmamados em áreas subtropicais tropicais e úmidas.(AU)
Assuntos
Animais , Bovinos , Nematoides/efeitos dos fármacos , Anti-Helmínticos/administração & dosagem , Anti-Helmínticos/economia , Criação de Animais Domésticos/economia , Gastroenteropatias/parasitologia , Gastroenteropatias/veterináriaRESUMO
This study aimed to identify the frequency of occurrence of Eimeria species in Holstein (taurine dairy cattle) and Nelore (zebu beef cattle) on 12 farms in the state of Goiás, Brazil. A total of 2,601 animals were evaluated, and the cattle were divided into the following age-group categories: up to three months old, four to eight months old, nine to 16 months old and cows. Fecal samples were collected directly from the rectum of all animals. None of the cattle presented any clinical signs of eimeriosis during the survey. From the results obtained, it could be concluded that higher rates of infection by Eimeria spp. were observed in Holstein cattle between the 1st and 16 th months of age and in Nelore cattle between the 1st and 8th months of age. Twelve and nine Eimeria species were diagnosed in Holstein and Nelore cattle, respectively. However, Eimeria zuernii was more prevalent in animals up to three months old, while Eimeria bovis was more common in the remaining categories (cattle aged four months and over). Future studies on the epidemiology and/or seasonality of infection by Eimeria species in cattle, from birth onwards, are needed in order to better understand the dynamics of E. zuernii and E. bovis occurrences, especially in cattle under three months of age.
Assuntos
Doenças dos Bovinos/parasitologia , Bovinos/parasitologia , Coccidiose/veterinária , Eimeria/isolamento & purificação , Fatores Etários , Animais , Brasil/epidemiologia , Doenças dos Bovinos/epidemiologia , Coccidiose/epidemiologia , Indústria de Laticínios , Carne VermelhaRESUMO
This study aimed to identify the frequency of occurrence of Eimeria species in Holstein (taurine dairy cattle) and Nelore (zebu beef cattle) on 12 farms in the state of Goiás, Brazil. A total of 2,601 animals were evaluated, and the cattle were divided into the following age-group categories: up to three months old, four to eight months old, nine to 16 months old and cows. Fecal samples were collected directly from the rectum of all animals. None of the cattle presented any clinical signs of eimeriosis during the survey. From the results obtained, it could be concluded that higher rates of infection by Eimeria spp. were observed in Holstein cattle between the 1st and 16 th months of age and in Nelore cattle between the 1st and 8th months of age. Twelve and nine Eimeria species were diagnosed in Holstein and Nelore cattle, respectively. However, Eimeria zuernii was more prevalent in animals up to three months old, while Eimeria bovis was more common in the remaining categories (cattle aged four months and over). Future studies on the epidemiology and/or seasonality of infection by Eimeria species in cattle, from birth onwards, are needed in order to better understand the dynamics of E. zuernii and E. bovis occurrences, especially in cattle under three months of age.(AU)
O presente trabalho teve como objetivo identificar a frequência das espécies de Eimeria spp. em bovinos holandeses (bovinos de leite) e Nelore (bovinos de corte) em 12 propriedades no Estado de Goiás. Foi avaliado um total de 2.601 animais, e em cada propriedade, os bovinos foram divididos nas seguintes categorias conforme a idade: até 3 meses, 4 a 8 meses, 9 a 16 meses e vacas. Amostras de fezes foram coletadas diretamente da ampola retal dos animais. Com base nos resultados obtidos pode-se concluir que em holandeses e Nelores, o maior número de bovinos infectados por Eimeria spp. foi observado do 1º ao 16º e do 1º ao 8º meses de idade, respectivamente. Não houve nenhum caso de eimeriose clínica durante a pesquisa. Doze e nove espécies de Eimeria foram diagnosticadas em holandeses e Nelores, respectivamente. As duas espécies mais frequentes foram Eimeria bovis e Eimeria zuernii, entretanto, E. zuernii foi mais prevalente em animais até os 3 meses de idade, enquanto que E. bovis foi a mais frequente nas demais categorias de bovinos, a partir dos 4 meses de idade. Futuros estudos relacionados à epidemiologia e/ou de sazonalidade da infecção por espécies Eimeria spp., em bovinos desde o seu nascimento, são necessários, a fim de melhor entender a dinâmica de ocorrência de E. zuernii e E. bovis principalmente em bezerros com até 3 meses de idade.(AU)
Assuntos
Animais , Bovinos , Eimeria/isolamento & purificação , Coccidiose/diagnóstico , Coccidiose/veterinária , Coccidiose/epidemiologia , Eimeriidae , Brasil/epidemiologiaRESUMO
Abstract This study aimed to identify the frequency of occurrence of Eimeria species in Holstein (taurine dairy cattle) and Nelore (zebu beef cattle) on 12 farms in the state of Goiás, Brazil. A total of 2,601 animals were evaluated, and the cattle were divided into the following age-group categories: up to three months old, four to eight months old, nine to 16 months old and cows. Fecal samples were collected directly from the rectum of all animals. None of the cattle presented any clinical signs of eimeriosis during the survey. From the results obtained, it could be concluded that higher rates of infection by Eimeria spp. were observed in Holstein cattle between the 1st and 16 th months of age and in Nelore cattle between the 1st and 8th months of age. Twelve and nine Eimeria species were diagnosed in Holstein and Nelore cattle, respectively. However, Eimeria zuernii was more prevalent in animals up to three months old, while Eimeria bovis was more common in the remaining categories (cattle aged four months and over). Future studies on the epidemiology and/or seasonality of infection by Eimeria species in cattle, from birth onwards, are needed in order to better understand the dynamics of E. zuernii and E. bovis occurrences, especially in cattle under three months of age.
Resumo O presente trabalho teve como objetivo identificar a frequência das espécies de Eimeria spp. em bovinos holandeses (bovinos de leite) e Nelore (bovinos de corte) em 12 propriedades no Estado de Goiás. Foi avaliado um total de 2.601 animais, e em cada propriedade, os bovinos foram divididos nas seguintes categorias conforme a idade: até 3 meses, 4 a 8 meses, 9 a 16 meses e vacas. Amostras de fezes foram coletadas diretamente da ampola retal dos animais. Com base nos resultados obtidos pode-se concluir que em holandeses e Nelores, o maior número de bovinos infectados por Eimeria spp. foi observado do 1º ao 16º e do 1º ao 8º meses de idade, respectivamente. Não houve nenhum caso de eimeriose clínica durante a pesquisa. Doze e nove espécies de Eimeria foram diagnosticadas em holandeses e Nelores, respectivamente. As duas espécies mais frequentes foram Eimeria bovis e Eimeria zuernii, entretanto, E. zuernii foi mais prevalente em animais até os 3 meses de idade, enquanto que E. bovis foi a mais frequente nas demais categorias de bovinos, a partir dos 4 meses de idade. Futuros estudos relacionados à epidemiologia e/ou de sazonalidade da infecção por espécies Eimeria spp., em bovinos desde o seu nascimento, são necessários, a fim de melhor entender a dinâmica de ocorrência de E. zuernii e E. bovis principalmente em bezerros com até 3 meses de idade.
Assuntos
Animais , Bovinos/parasitologia , Doenças dos Bovinos/parasitologia , Coccidiose/veterinária , Eimeria/isolamento & purificação , Brasil/epidemiologia , Doenças dos Bovinos/epidemiologia , Fatores Etários , Coccidiose/epidemiologia , Indústria de Laticínios , Carne VermelhaRESUMO
Este trabalho objetivou avaliar a prevalência e a sazonalidade da infecção natural por parasitos gastrintestinais em bubalinos de aptidão leiteira de diferentes categorias, no município de Bandeirantes, Mato Grosso do Sul. Foram avaliados 41 búfalos da raça Murrah, divididos em três categorias, sendo 11 lactentes, com idade de 0 a 8 meses, 10 desmamados, de 8 a 18 meses, e 20 fêmeas adultas com idade superior a 18 meses. Os animais adultos apresentaram-se livres de parasitismo ou com carga parasitária muito baixa. A categoria lactente apresentou pico de contagem de ovos por grama de fezes (OPG=2038) em novembro, quando a precipitação acumulada foi de 69,3 mm e a temperatura 25,95 °C, enquanto a menor contagem de ovos (167) ocorreu em maio, dois meses após pico de 234,68 mm e 20,59 °C. Os búfalos desmamados apresentaram dois picos de OPG, de 1288 e 875, em setembro e junho, com precipitação de 41,45 e 18,4 mm e temperatura de 24,16 e 20,69 °C, respectivamente. Foi observada correlação significativa (p=0,01) e negativa (r=-0,33) entre o OPG dos bezerros lactentes e precipitação pluviométrica. Os parasitos gastrintestinais mais frequentes foram Haemonchus sp. e Cooperia sp.(AU)
This study evaluated the prevalence and seasonality of natural infection by gastrointestinal parasites and the susceptibility of different dairy buffalo categories in Bandeirantes, state of Mato Grosso do Sul, Brazil. Forty-one Murrah buffaloes were divided into three categories, 11 suckling calves (0-8 months old), 10 weaned calves (8-18 months old), and 20 adult females over the age of 18 months. Adult animals were free from parasitism or showed very low parasite load. The suckling calves showed a peak of egg per gram of feces (EPG = 2038) in November, when the average rainfall was 69.3 mm and the temperature 25.95 °C, while the lowest egg count (167) occurred in May, two months after the peak of 234.68 mm and 20.59 °C. Weaned calves showed two peaks of EPG from 1288.89 and 875 in September and June, with rainfall of 41.45 and 18.4 mm, temperature 24.16 and 20.69 °C, respectively. Significant (p = 0.01) and negative (r = -0.33) correlation between the EPG of suckling calves and precipitation was observed. The most common gastrointestinal parasites were Haemonchus sp. and Cooperia sp.(AU)
Assuntos
Animais , Búfalos/parasitologia , Helmintíase/epidemiologia , Trato Gastrointestinal/parasitologia , Eimeria , Haemonchus , Estações do Ano , Contagem de Ovos de Parasitas/veterináriaRESUMO
Abstract This study evaluated the prevalence and seasonality of natural infection by gastrointestinal parasites and the susceptibility of different dairy buffalo categories in Bandeirantes, state of Mato Grosso do Sul, Brazil. Forty-one Murrah buffaloes were divided into three categories, 11 suckling calves (0-8 months old), 10 weaned calves (8-18 months old), and 20 adult females over the age of 18 months. Adult animals were free from parasitism or showed very low parasite load. The suckling calves showed a peak of egg per gram of feces (EPG = 2038) in November, when the average rainfall was 69.3 mm and the temperature 25.95 ºC, while the lowest egg count (167) occurred in May, two months after the peak of 234.68 mm and 20.59 ºC. Weaned calves showed two peaks of EPG from 1288.89 and 875 in September and June, with rainfall of 41.45 and 18.4 mm, temperature 24.16 and 20.69 ºC, respectively. Significant (p = 0.01) and negative (r = -0.33) correlation between the EPG of suckling calves and precipitation was observed. The most common gastrointestinal parasites were Haemonchus sp. and Cooperia sp.
Resumo Este trabalho objetivou avaliar a prevalência e a sazonalidade da infecção natural por parasitos gastrintestinais em bubalinos de aptidão leiteira de diferentes categorias, no município de Bandeirantes, Mato Grosso do Sul. Foram avaliados 41 búfalos da raça Murrah, divididos em três categorias, sendo 11 lactentes, com idade de 0 a 8 meses, 10 desmamados, de 8 a 18 meses, e 20 fêmeas adultas com idade superior a 18 meses. Os animais adultos apresentaram-se livres de parasitismo ou com carga parasitária muito baixa. A categoria lactente apresentou pico de contagem de ovos por grama de fezes (OPG=2038) em novembro, quando a precipitação acumulada foi de 69,3 mm e a temperatura 25,95 ºC, enquanto a menor contagem de ovos (167) ocorreu em maio, dois meses após pico de 234,68 mm e 20,59 ºC. Os búfalos desmamados apresentaram dois picos de OPG, de 1288 e 875, em setembro e junho, com precipitação de 41,45 e 18,4 mm e temperatura de 24,16 e 20,69 ºC, respectivamente. Foi observada correlação significativa (p=0,01) e negativa (r=-0,33) entre o OPG dos bezerros lactentes e precipitação pluviométrica. Os parasitos gastrintestinais mais frequentes foram Haemonchus sp. e Cooperia sp.
RESUMO
Este trabalho objetivou avaliar a prevalência e a sazonalidade da infecção natural por parasitos gastrintestinais em bubalinos de aptidão leiteira de diferentes categorias, no município de Bandeirantes, Mato Grosso do Sul. Foram avaliados 41 búfalos da raça Murrah, divididos em três categorias, sendo 11 lactentes, com idade de 0 a 8 meses, 10 desmamados, de 8 a 18 meses, e 20 fêmeas adultas com idade superior a 18 meses. Os animais adultos apresentaram-se livres de parasitismo ou com carga parasitária muito baixa. A categoria lactente apresentou pico de contagem de ovos por grama de fezes (OPG=2038) em novembro, quando a precipitação acumulada foi de 69,3 mm e a temperatura 25,95 °C, enquanto a menor contagem de ovos (167) ocorreu em maio, dois meses após pico de 234,68 mm e 20,59 °C. Os búfalos desmamados apresentaram dois picos de OPG, de 1288 e 875, em setembro e junho, com precipitação de 41,45 e 18,4 mm e temperatura de 24,16 e 20,69 °C, respectivamente. Foi observada correlação significativa (p=0,01) e negativa (r=-0,33) entre o OPG dos bezerros lactentes e precipitação pluviométrica. Os parasitos gastrintestinais mais frequentes foram Haemonchus sp. e Cooperia sp.
This study evaluated the prevalence and seasonality of natural infection by gastrointestinal parasites and the susceptibility of different dairy buffalo categories in Bandeirantes, state of Mato Grosso do Sul, Brazil. Forty-one Murrah buffaloes were divided into three categories, 11 suckling calves (0-8 months old), 10 weaned calves (8-18 months old), and 20 adult females over the age of 18 months. Adult animals were free from parasitism or showed very low parasite load. The suckling calves showed a peak of egg per gram of feces (EPG = 2038) in November, when the average rainfall was 69.3 mm and the temperature 25.95 °C, while the lowest egg count (167) occurred in May, two months after the peak of 234.68 mm and 20.59 °C. Weaned calves showed two peaks of EPG from 1288.89 and 875 in September and June, with rainfall of 41.45 and 18.4 mm, temperature 24.16 and 20.69 °C, respectively. Significant (p = 0.01) and negative (r = -0.33) correlation between the EPG of suckling calves and precipitation was observed. The most common gastrointestinal parasites were Haemonchus sp. and Cooperia sp.
Assuntos
Animais , Búfalos/parasitologia , Eimeria , Haemonchus , Helmintíase/epidemiologia , Trato Gastrointestinal/parasitologia , Contagem de Ovos de Parasitas/veterinária , Estações do AnoRESUMO
The main importance of eimeriosis in cattle is due to lower performance shown with the disease in its sub-clinical form. This study evaluated the efficacy of lasalocid used against Eimeria spp. parasitizing calves. We also evaluated the weight gain of calves submitted to different treatments and analyzed some epidemiological factors that might interfere with Eimeria infection; 288 calves were used in the study. The calves of treatment 1 received protein mineral salt in low consumption without lasalocid, while the calves of treatment 2 received protein mineral salt on low consumption with lasalocid, administered orally to 4 to 10-month-old calves. Harvest of feces and weight control was made on days 0 (before the start of the experiment), at weaning, and 30 and 60 days after weaning (DAW). Evaluation of some epidemiological factors which could be related to infection by Eimeria spp. of the calves, such as weaning, sex and time of year, were analyzed, taking into account the results regarding the 144 calves of the control group. Nine species of Eimeria were identified in descending order: E. brasiliensis, E. wyomingensis, E. bovis, E. canadian, E. zuernii, E. auburnensis, E. ellipsoidalis, E. pellita and E. cylindrica. Unexpectedly, decrease in parasite load could be observed after weaning. Even the farm did not adopt management measures aimed for greater productivity, as Artificial Insemination in Fixed Time, which in turn ends up with increase of the number of births and animal unit per hectare at a certain period of year, high parasitism of coccidia was diagnosed in calves of the control group. Oocyst counts per gram (OPG) of calves treated with lasalocid were significantly lower (P <= 0.05) in the control group. The compound achieved 95% efficacy against the parasite in question. At the end of the study, calves fed lasalocid gained on average 7.2kg (p <=0.05) more than calves in the control group. [...](AU)
A principal importância da eimeriose em bovinos, se deve ao baixo desempenho produtivo que os animais demonstram quando esta enfermidade apresenta-se sob a forma sub-clínica. Como objetivos, o presente trabalho avaliou a eficácia do uso da lasalocida sódica contra espécies de Eimeria spp. parasitando bezerros; avaliou também o desempenho ponderal dos animais submetidos aos diferentes tratamentos e analisou alguns fatores epidemiológicos que possam interferir na infecção por Eimeria nos bezerros. Foram utilizados 288 bezerros no dia 0 do estudo. Os animais pertencentes ao tratamento 01 receberam sal mineral proteinado de baixo consumo sem adição de lasalocida, enquanto que os bezerros do Tratamento 02 sal mineral proteinado de baixo consumo, com adição de lasalocida sódica, administrado via oral para bezerros dos quatro/cinco/seis meses até dez meses de idade. Colheita de fezes e pesagem dos animais foram realizadas nos dias 0 (antes do início do experimento), na desmama, 30 e 60 dias após desmama (DPD). A avaliação de alguns fatores epidemiológicos que pudessem ser relacionados com a infecção por Eimeria spp nos bezerros, como o desmame, sexo e época do ano, foram analisados neste estudo, levando-se em consideração os resultados encontrados durante todo estudo, para os 144 animais pertencentes ao grupo controle. Foram identificadas nove espécies de Eimeria nos bezerros em ordem decrescente: E. brasiliensis, E. wyomingensis, E. bovis, E. canadenses, E. zuernii, E. auburnensis, E. ellipsoidalis, E. pellita e E. cylindrica. Inesperadamente, diminuição na carga parasitária dos animais pode ser observada após o desmame. Mesmo a fazenda não adotando medidas de manejo que visam maior produtividade como a Inseminação Artificial em Tempo Fixo, que por sua vez acaba aumentando o número de nascimentos e unidade animal/hectare em uma determinada [...](AU)
Assuntos
Animais , Bovinos , Eimeria , Lasalocida/análise , Lasalocida/administração & dosagem , Desmame , Coccidiose/epidemiologia , Resultado do TratamentoRESUMO
A principal importância da eimeriose em bovinos, se deve ao baixo desempenho produtivo que os animais demonstram quando esta enfermidade apresenta-se sob a forma sub-clínica. Como objetivos, o presente trabalho avaliou a eficácia do uso da lasalocida sódica contra espécies de Eimeria spp. parasitando bezerros; avaliou também o desempenho ponderal dos animais submetidos aos diferentes tratamentos e analisou alguns fatores epidemiológicos que possam interferir na infecção por Eimeria nos bezerros. Foram utilizados 288 bezerros no dia 0 do estudo. Os animais pertencentes ao tratamento 01 receberam sal mineral proteinado de baixo consumo sem adição de lasalocida, enquanto que os bezerros do Tratamento 02 sal mineral proteinado de baixo consumo, com adição de lasalocida sódica, administrado via oral para bezerros dos quatro/cinco/seis meses até dez meses de idade. Colheita de fezes e pesagem dos animais foram realizadas nos dias 0 (antes do início do experimento), na desmama, 30 e 60 dias após desmama (DPD). A avaliação de alguns fatores epidemiológicos que pudessem ser relacionados com a infecção por Eimeria spp nos bezerros, como o desmame, sexo e época do ano, foram analisados neste estudo, levando-se em consideração os resultados encontrados durante todo estudo, para os 144 animais pertencentes ao grupo controle. Foram identificadas nove espécies de Eimeria nos bezerros em ordem decrescente: E. brasiliensis, E. wyomingensis, E. bovis, E. canadenses, E. zuernii, E. auburnensis, E. ellipsoidalis, E. pellita e E. cylindrica. Inesperadamente, diminuição na carga parasitária dos animais pode ser observada após o desmame. Mesmo a fazenda não adotando medidas de manejo que visam maior produtividade como a Inseminação Artificial em Tempo Fixo, que por sua vez acaba aumentando o número de nascimentos e unidade animal/hectare em uma determinada época do ano, elevado parasitismo pelo coccídio em questão foi diagnosticado nos bezerros pertencentes ao grupo controle. Talvez a época do ano em que o estudo foi realizado pode ter influenciado neste aspecto. As contagens de oocistos por grama (OoPG) de fezes para Eimeria dos animais tratados com lasalocida foram estatisticamente inferiores (P≤ 0,05) as do grupo controle após o início do estudo. O composto alcançou eficácia ≥ 95% contra o parasito em questão. No final do estudo, os animais que receberam lasalocida ganharam em média, 7,2kg a mais (P≤ 0,05) que os bezerros pertencentes ao grupo controle. Em propriedades que tem como objetivo a venda de bezerros logo após a desmama, recomenda-se o início do tratamento com a lasalocida, junto ao creep-feeding, a partir de três messes de idade, uma vez que diferencial no ganho em peso médio dos bezerros tratados foi significativamente (P≤ 0,05) mais elevado, em comparação ao grupo controle, após cinco meses de tratamento com o referido composto. Apesar de a lasalocida ser utilizada como um aditivo alimentar para animais, a diferença no ganho em peso vivo médio entre animais tratados com a lasalocida, em comparação a animais pertencentes ao grupo controle, também pode ser relacionada, em partes, a infecção dos animais por Eimeria spp., conforme discutido neste artigo, entretanto, futuros estudos devem ser conduzidos para comprovar esta hipótese.(AU)
The main importance of eimeriosis in cattle is due to lower performance shown with the disease in its sub-clinical form. This study evaluated the efficacy of lasalocid used against Eimeria spp. parasitizing calves. We also evaluated the weight gain of calves submitted to different treatments and analyzed some epidemiological factors that might interfere with Eimeria infection; 288 calves were used in the study. The calves of treatment 1 received protein mineral salt in low consumption without lasalocid, while the calves of treatment 2 received protein mineral salt on low consumption with lasalocid, administered orally to 4 to 10-month-old calves. Harvest of feces and weight control was made on days 0 (before the start of the experiment), at weaning, and 30 and 60 days after weaning (DAW). Evaluation of some epidemiological factors which could be related to infection by Eimeria spp. of the calves, such as weaning, sex and time of year, were analyzed, taking into account the results regarding the 144 calves of the control group. Nine species of Eimeria were identified in descending order: E. brasiliensis, E. wyomingensis, E. bovis, E. canadian, E. zuernii, E. auburnensis, E. ellipsoidalis, E. pellita and E. cylindrica. Unexpectedly, decrease in parasite load could be observed after weaning. Even the farm did not adopt management measures aimed for greater productivity, as Artificial Insemination in Fixed Time, which in turn ends up with increase of the number of births and animal unit per hectare at a certain period of year, high parasitism of coccidia was diagnosed in calves of the control group. Oocyst counts per gram (OPG) of calves treated with lasalocid were significantly lower (P≤ 0.05) in the control group. The compound achieved ≥ 95% efficacy against the parasite in question. At the end of the study, calves fed lasalocid gained on average 7.2kg (p≤ 0.05) more than calves in the control group. For a farm that aims to sell calves soon after weaning, is recommended to start treatment with lasalocid, with the creep-feeding, from an age of three months on, since the weight gain calves treated with lasalocid was significantly (p=0.05) higher compared with the weight gain of the control group after five months of treatment. The difference in weight gain of calves treated with lasalocid compared with caves in the control group may also be partially related to the infection by Eimeria spp., as discussed in this paper.(AU)
Assuntos
Animais , Bovinos , Coccidiose/epidemiologia , Eimeria , Lasalocida/administração & dosagem , Lasalocida/análise , Desmame , Resultado do TratamentoRESUMO
ABSTRACT: The main importance of eimeriosis in cattle is due to lower performance shown with the disease in its sub-clinical form. This study evaluated the efficacy of lasalocid used against Eimeria spp. parasitizing calves. We also evaluated the weight gain of calves submitted to different treatments and analyzed some epidemiological factors that might interfere with Eimeria infection; 288 calves were used in the study. The calves of treatment 1 received protein mineral salt in low consumption without lasalocid, while the calves of treatment 2 received protein mineral salt on low consumption with lasalocid, administered orally to 4 to 10-month-old calves. Harvest of feces and weight control was made on days 0 (before the start of the experiment), at weaning, and 30 and 60 days after weaning (DAW). Evaluation of some epidemiological factors which could be related to infection by Eimeria spp. of the calves, such as weaning, sex and time of year, were analyzed, taking into account the results regarding the 144 calves of the control group. Nine species of Eimeria were identified in descending order: E. brasiliensis, E. wyomingensis, E. bovis, E. canadian, E. zuernii, E. auburnensis, E. ellipsoidalis, E. pellita and E. cylindrica. Unexpectedly, decrease in parasite load could be observed after weaning. Even the farm did not adopt management measures aimed for greater productivity, as Artificial Insemination in Fixed Time, which in turn ends up with increase of the number of births and animal unit per hectare at a certain period of year, high parasitism of coccidia was diagnosed in calves of the control group. Oocyst counts per gram (OPG) of calves treated with lasalocid were significantly lower (P 0.05) in the control group. The compound achieved 95% efficacy against the parasite in question. At the end of the study, calves fed lasalocid gained on average 7.2kg (p 0.05) more than calves in the control group. For a farm that aims to sell calves soon after weaning, is recommended to start treatment with lasalocid, with the creep-feeding, from an age of three months on, since the weight gain calves treated with lasalocid was significantly (p=0.05) higher compared with the weight gain of the control group after five months of treatment. The difference in weight gain of calves treated with lasalocid compared with caves in the control group may also be partially related to the infection by Eimeria spp., as discussed in this paper.
RESUMO: A principal importância da eimeriose em bovinos, se deve ao baixo desempenho produtivo que os animais demonstram quando esta enfermidade apresenta-se sob a forma sub-clínica. Como objetivos, o presente trabalho avaliou a eficácia do uso da lasalocida sódica contra espécies de Eimeria spp. parasitando bezerros; avaliou também o desempenho ponderal dos animais submetidos aos diferentes tratamentos e analisou alguns fatores epidemiológicos que possam interferir na infecção por Eimeria nos bezerros. Foram utilizados 288 bezerros no dia 0 do estudo. Os animais pertencentes ao tratamento 01 receberam sal mineral proteinado de baixo consumo sem adição de lasalocida, enquanto que os bezerros do Tratamento 02 sal mineral proteinado de baixo consumo, com adição de lasalocida sódica, administrado via oral para bezerros dos quatro/cinco/seis meses até dez meses de idade. Colheita de fezes e pesagem dos animais foram realizadas nos dias 0 (antes do início do experimento), na desmama, 30 e 60 dias após desmama (DPD). A avaliação de alguns fatores epidemiológicos que pudessem ser relacionados com a infecção por Eimeria spp nos bezerros, como o desmame, sexo e época do ano, foram analisados neste estudo, levando-se em consideração os resultados encontrados durante todo estudo, para os 144 animais pertencentes ao grupo controle. Foram identificadas nove espécies de Eimeria nos bezerros em ordem decrescente: E. brasiliensis, E. wyomingensis, E. bovis, E. canadenses, E. zuernii, E. auburnensis, E. ellipsoidalis, E. pellita e E. cylindrica. Inesperadamente, diminuição na carga parasitária dos animais pode ser observada após o desmame. Mesmo a fazenda não adotando medidas de manejo que visam maior produtividade como a Inseminação Artificial em Tempo Fixo, que por sua vez acaba aumentando o número de nascimentos e unidade animal/hectare em uma determinada época do ano, elevado parasitismo pelo coccídio em questão foi diagnosticado nos bezerros pertencentes ao grupo controle. Talvez a época do ano em que o estudo foi realizado pode ter influenciado neste aspecto. As contagens de oocistos por grama (OoPG) de fezes para Eimeria dos animais tratados com lasalocida foram estatisticamente inferiores (P 0,05) as do grupo controle após o início do estudo. O composto alcançou eficácia 95% contra o parasito em questão. No final do estudo, os animais que receberam lasalocida ganharam em média, 7,2kg a mais (P 0,05) que os bezerros pertencentes ao grupo controle. Em propriedades que tem como objetivo a venda de bezerros logo após a desmama, recomenda-se o início do tratamento com a lasalocida, junto ao creep-feeding, a partir de três messes de idade, uma vez que diferencial no ganho em peso médio dos bezerros tratados foi significativamente (P 0,05) mais elevado, em comparação ao grupo controle, após cinco meses de tratamento com o referido composto. Apesar de a lasalocida ser utilizada como um aditivo alimentar para animais, a diferença no ganho em peso vivo médio entre animais tratados com a lasalocida, em comparação a animais pertencentes ao grupo controle, também pode ser relacionada, em partes, a infecção dos animais por Eimeria spp., conforme discutido neste artigo, entretanto, futuros estudos devem ser conduzidos para comprovar esta hipótese.