Biomarkers of gastrointestinal nematodes in beef cattle raised in a tropical area.

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.

Efficiency of fluralaner pour-on in different strategic control protocols against Rhipicephalus microplus on Brangus cattle in a tropical area.

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.

Synergism of macrocyclic lactones against Haemonchus contortus.

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.

Poisoning of calves reared with cows treated with abamectin.

The aim of the present study was to describe an outbreak of poisoning by abamectin in calves less than four months of age whose mothers were treated with a pour-on product containing this ingredient. The diagnosis was based on the history, clinical signs, absence of macroscopic and histopathological findings (characteristic of this type of poisoning) and the detection of abamectin in tissues of the animals submitted to necropsy. Based on this report, the recommendation is the use with caution of pour-on formulations containing abamectin on cows having given birth less than four months earlier.

Effects of supplementation on production and age anticipation at first mating of ewe lambs in tropical pastures.

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.

Status of Rhipicephalus microplus resistance to ivermectin, fipronil and fluazuron in Mato Grosso do Sul, Brazil.

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.

First report of Dermatobia hominis resistant to doramectin in cattle.

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 µg/kg live weight (LW), and control group - dosed with saline solution 1 mL/50 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 72 h of treatment, there was a significant reduction (p < 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.

Combination of quercetin and ivermectin: In vitro and in vivo effects against Haemonchus contortus.

The aim of the present study was to evaluate the in vitro effect of quercetin combined with ivermectin (IVM) on Haemonchus contortus larvae and adults with different resistance profiles and demonstrate the in vivo anthelmintic action of this combination when used in sheep naturally infected. The effect of combination was evaluated based on the analysis of the mean effective concentration (EC50) obtained for larvae using the larval migration inhibition test and for adults using the motility test on females. The tests with larvae and adults were conducted using isolates with different degrees of susceptibility to IVM (sensitive, intermediate and highly resistant). The in vivo effect was evaluated based on the reduction in the egg count (FEC) and reduction in the count of adult helminths recovered after parasitological necropsy. Using the combination of quercetin with IVM, it was observed that in larvae, quercetin did not significantly reduce the EC50 for IVM in the sensitive and highly resistant isolates, but led to a significant reduction in the EC50 for IVM in the intermediate isolate. In adults, quercetin did not significantly reduce the EC50 for IVM in any of the isolates. No significant effect of the combination was found regarding the reduction in FEC or total count of parasites. The results of the in vitro and in vivo tests performed in the present study on quercetin activity underscore the importance of evaluating resistance-reversing agents among different stages of parasite development as well as among isolates with different resistance profiles. The action of quercetin combined with IVM on the motility of H. contortus larvae and adults was influenced by the degree of resistance and development stage of the parasite. The combination was effective only on intermediate resistant larvae. No action of the combination against adults was found. Moreover, this combination, when administered through the intra-abomasal route, was not effective at reducing the FEC and parasite load of naturally infected sheep.

Discovery of potential ovicidal natural products using metabolomics.

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.

Retrospective study of epidemiological, clinical and pathological findings of bovine babesiosis in Mato Grosso do Sul, Brazil (1995 -2017).

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.

Eimeria species in dairy and beef cattle of different ages in Goiás state, Brazil.

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.

Eimeria species in dairy and beef cattle of different ages in Goiás state, Brazil / Espécies de Eimeria em bovinos de leite e corte de diferentes idades no Estado de Goiás, Brasil

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.

Effect of creep-fed supplement on the susceptibility of pasture-grazed suckling lambs to gastrointestinal helminths.

This study evaluated the effect of creep feeding a protein supplement on the susceptibility of suckling lambs to infection with gastrointestinal helminths. Male and female lambs were grazed on Brachiaria spp. pastures next to their mothers. Animals were allocated to one of two treatments: creep feeding (261g/d) and control (no supplementation). The trial period was the suckling of lambs during two years of study: May-October 2013 and March-July 2014. Supplementary creep feeding of lambs improved animal performance (P<0.05). Creep-fed lambs reached 18kg body weight in 64 d, but unsupplemented lambs required 77 d to reach the same weight. Lambs were susceptible to helminth infection during lactation; lambs in both treatments had high fecal egg counts (FECs), with means >1000 eggs per gram, as early as 45days of age, when the daily grazing time per animal increased. Creep feeding reduced the FECs of suckling lambs >60days of age in infections dominated by Haemonchus contortus. Totals of 20 and 48 anthelmintic treatments were administered to the supplemented and unsupplemented animals, respectively. The effect of this variable, however, was significant (P<0.05) only after 60days, when nine and 28 treatments had been administered to the supplemented and unsupplemented lambs, respectively. The number of strongyloid larvae recovered from the paddock did not differ significantly (P >0.05) between the two treatments, indicating similar challenges by infective larvae to both groups. The supplementation of lambs by creep feeding can thus be a strategy for the sustainable control of helminth infection, because it reduces the dependence on anthelmintic treatment.

Avaliação da eficácia da lasalocida e de alguns fatores epidemiológicos de Eimeria spp. parasitando bezerros Nelore mantidos em regime de pastejo / Effectiveness of lasalocid assessment and some epidemiological factors of Eimeria spp. parasitizing Nellore calves kept on pasture

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)

First genetic identification of Cryptosporidium parvum subtype IIaA14G2R1in beef cattle in Brazil.

The presence of Cryptosporidium spp. in a cattle herd registered with an outbreak of diarrhea was investigated and the the molecular subtyping of Cryptosporidium parvum was characterized. Fecal samples from 85 Nellore beef cattle (Bos indicus) were collected and examined with Ziehl-Neelsen modified staining method. Fifty-four cattle (63.52%) had Cryptosporidium spp. oocysts in their feces. Fragments of genes encoding the 18S ribosomal RNA subunit and a 60-kDa glycoprotein (gp60) were amplified by nested PCR accomplished in the 11 most heavily parasitized samples, and the amplicons were sequenced. Eight of the 11 analyzed samples were positive for 18S rRNA sequences and identified monospecific infections with C. parvum. Seven samples were positive for gp60 and identified subtypes IIaA15G2R1 (6/11) and IIaA14G2R1 (1/11). This report is the first for C. parvum subtype IIaA14G2R1 in beef cattle in Brazil.

Multispecies resistance of cattle gastrointestinal nematodes to long-acting avermectin formulations in Mato Grosso do Sul.

The use of long-acting avermectins (AVMs) in cattle to treat infections with gastrointestinal nematodes was common in Brazil until its prohibition by state authorities. The prohibition; however, was rescinded in 2015, but a scientific discussion of the pros and cons of the use of these formulations is necessary. We evaluated the levels of resistance to 1.0 and 3.5% doramectin and to 3.15% ivermectin in cattle. The worms in animals treated with 3.5% doramectin were characterized by the suppression of oviposition and by a higher proportion of adult females carrying no eggs. Haemonchus placei, Cooperia punctata, C. pectinata, C. spatulata, and Oesophagostomum radiatum were resistant to the above compositions. The administration of long-acting AVM formulations did not result in a higher efficacy against these helminth populations.

Efficacy of extracts from plants of the Brazilian Pantanal against Rhipicephalus (Boophilus) microplus / Eficácia de extratos de plantas do Pantanal brasileiro sobre Rhipicephalus (Boophilus) microplus

This research evaluated the in vitro acaricidal activity of extracts from 21 plant species from the Pantanal of Mato Grosso do Sul. During stage I, a larval immersion test was performed using three extract concentrations (5%, 20%, and 40%). During stage II, we used only plants that showed over 95% efficiency at the 40% concentration in stage I in an amount sufficient for the adult immersion test. Aeschynomene denticulata, Angelonia hirta, Aspilia latissima, Caperonia castaneifolia, Centratherum punctatum, Crotalaria micans, Diodia kuntzei, Echinodorus paniculatus, Hyptis mutabilis, Lantana canescens, Melanthera latifolia, Ocotea diospyrifolia, Richardia grandiflora, Sebastiana hispida, Tocoyena formosa, Zanthoxylum rigidum, and Sesbania virgata (fruit extract) showed acaricidal activity against the larval stage of Rhipicephalus (Boophilus) microplus higher than 95% at a 40% (w/v) concentration, while Hippocratea volubilis and Randia armata showed moderate efficacy and Croton glandulosus and Senna obtusifolia had no effect. The M. latifolia, A. hirta, R. grandiflora, and A. latissima raw extracts were evaluated for their activity against adults, and only A. hirta showed an efficacy close to 90%. Eighteen extracts had an efficacy of up to 95% against larvae at a 40% concentration, seven extracts were effective at 20%, and only one (Sebastiana hispida) was effective at a 5% concentration.

Este trabalho avaliou a atividade acaricida in vitro de extratos de 21 espécies de plantas do Pantanal de Mato Grosso do Sul. Na etapa I, foi realizado um teste de imersão larval utilizando três concentrações de extrato (5%, 20% e 40%). Na etapa II, utilizou-se apenas as plantas que apresentaram eficácia superior a 95%, na concentração de 40% na etapa I e que apresentasse quantidade suficiente para o teste de imersão de adulto. Aeschynomene denticulata, Angelonia hirta, Aspilia latissima, Caperonia castaneifolia, Centratherum punctatum, Crotalaria micans, Diodia kuntzei, Echinodorus paniculatus, Hyptis mutabilis, Lantana canescens, Melanthera latifolia, Ocotea diospyrifolia, Richardia grandiflora, Sebastiana hispida, Tocoyena formosa, Zanthoxylum rigidum e Sesbania virgata (extrato do fruto) apresentaram atividade acaricida sobre larvas de Rhipicephalus (Boophilus) microplus superior a 95% na concentração de 40% (w/v), enquanto Hippocratea volubilis e Randia armata apresentaram eficácia moderada e Croton glandulosus e Senna obtusifolia não apresentaram efeito acaricida. Os extratos brutos de M. latifolia, A. hirta, R. grandiflora e A. latissima foram avaliados sobre adultos e A. hirta apresentou eficácia próxima de 90%. Dezoito extratos apresentaram eficácia de até 95%, contra larvas, na concentração de 40%, sete extratos foram eficazes a 20% e apenas um (Sebastiana hispida) foi eficaz na concentração de 5%.

Eimeria species in young and adult sheep raised under intensive and / or semi-intensive systems of a herd from Umuarama city, Parana State, Brazil / Espécies de Eimeria em ovinos jovens e adultos criados em sistema intensivo e / ou semi - intensivo de um rebanho da cidade de Umuarama, Estado do Paraná, Brasil

The present study aimed to identify Eimeria species in young and adult sheep raised under intensive and / or semi-intensive systems of a herd from Umuarama city, Parana State, Brazil using the traditional diagnostic methods and to correlate the infection level/types of infection in the different age/system in this herd. Fecal samples were collected from the rectum of 210 sheep and were subjected to laboratory analysis to differentiate the species. Furthermore, animals were observed to determine the occurrences of the clinical or subclinical forms of eimeriosis. Out of the 210 collected fecal samples, 147 (70%) were positive for Eimeria oocysts, and 101 (47.86%) belonged to young animals that were raised under intensive and / or semi-intensive farming systems. Oocysts from 9 species of Eimeria parasites were identified in the sheep at the following prevalence rates: E. crandallis, 50.0%; E. parva, 21.6%; E. faurei, 8.1%; E. ahsata, 8.1%; E. intricata, 5.4%; E. granulosa , 2.7%; E. ovinoidalis , 2.0%; E. ovina , 1.3%; and E. bakuensis , 0.6%. There were no differences regarding the more frequent Eimeria species among the different ages of animals or between the different farming management systems. Based on these data, E. crandallis was the most prevalent, followed by E. parva and E. faurei species, regardless of the age. Higher parasitism was diagnosed in the young animals that were raised in a confinement regime, and the disease found in the herd was classified as subclinical. Further studies should be conducted in this herd, to verify if the eimeriosis subclinical can cause damage especially in young animals with a high level of infection.

O presente trabalho teve como objetivo realizar a identificação das espécies de Eimeria em ovinos jovens e adultos, criados em sistema intensivo e/ou semi-intensivo, de um rebanho da cidade de Umuarama, estado do Paraná, Brasil, utilizando-se métodos tradicionais de diagnóstico, bem como correlacionando o grau de infecção/tipo de infecção nas diferentes categorias animal presentes no rebanho. Amostras de fezes de 210 ovinos foram colhidas diretamente da ampola retal desses animais. Em seguida, procedeu-se à diferenciação das espécies em laboratório. Além disso, os animais foram observados, diariamente, durante o período de 20 dias, após a colheita de fezes, a fim de se evidenciar se a eimeriose ocorreu de forma clínica ou subclínica nos rebanhos. Das 210 amostras de fezes colhidas, 147 (70%) foram positivas para oocistos de Eimeria. Dentre as 210 amostras, 101 (47,8%) pertenciam aos animais jovens criados no sistema intensivo e/ou semi-intensivo. Foram identificados oocistos de nove espécies de Eimeria parasitas de ovinos, com a seguinte prevalência: E. crandallis (50,0%), E. parva (21,6%), E. faurei (8,1%), E. ahsata (8,1%), E. intrincata (5,4%), E. granulosa (2,7%), E. ovinoidalis (2,0%), E. ovina (1,3%) e E. bakuensis (0,7%). Não houve diferença quanto às espécies de Eimeria mais frequentes, entre as diferentes idades dos animais e também entre os diferentes regimes de criação (manejo). Diante do exposto, E. crandallis foi a espécies mais prevalente, seguida da E. parva e E. faurei, independente da idade dos animais. Maior nível de parasitismo foi encontrado nos animais jovens criados em regime de confinamento, e a enfermidade foi classificada como eimeriose subclínica, independente da idade dos animais. Futuros estudos deverão ser conduzidos neste rebanho, a fim de evidenciar se a eimeriose subclínica desencadeia danos aos animais, especialmente nos jovens criados em confinamento.

Efficacy of extracts from plants of the Brazilian Pantanal against Rhipicephalus (Boophilus) microplus.

This research evaluated the in vitro acaricidal activity of extracts from 21 plant species from the Pantanal of Mato Grosso do Sul. During stage I, a larval immersion test was performed using three extract concentrations (5%, 20%, and 40%). During stage II, we used only plants that showed over 95% efficiency at the 40% concentration in stage I in an amount sufficient for the adult immersion test. Aeschynomene denticulata, Angelonia hirta, Aspilia latissima, Caperonia castaneifolia, Centratherum punctatum, Crotalaria micans, Diodia kuntzei, Echinodorus paniculatus, Hyptis mutabilis, Lantana canescens, Melanthera latifolia, Ocotea diospyrifolia, Richardia grandiflora, Sebastiana hispida, Tocoyena formosa, Zanthoxylum rigidum, and Sesbania virgata (fruit extract) showed acaricidal activity against the larval stage of Rhipicephalus (Boophilus) microplus higher than 95% at a 40% (w/v) concentration, while Hippocratea volubilis and Randia armata showed moderate efficacy and Croton glandulosus and Senna obtusifolia had no effect. The M. latifolia, A. hirta, R. grandiflora, and A. latissima raw extracts were evaluated for their activity against adults, and only A. hirta showed an efficacy close to 90%. Eighteen extracts had an efficacy of up to 95% against larvae at a 40% concentration, seven extracts were effective at 20%, and only one (Sebastiana hispida) was effective at a 5% concentration.