Anthelminthic resistant populations of Haemonchus contortus are a major problem in sheep rearing, but plant extracts may offer viable alternative treatments. In our preliminary studies, Piptadenia viridiflora was frequently selected by sheep grazing in the Cerrado. The present research evaluated its in vitro and in vivo anthelmintic activity. The HPLC chromatograms of P. viridiflora aqueous extract (AE) and ethanolic extract (EE) showed the presence of flavonoids. The total condensed tannin (proanthocyanidin) was 0.2 and 1.01% in AE and EE, respectively. In an egg hatching inhibition (EHI) test, the LC90 of AE was 2.4mg/mL, and, of EE, was 2.1mg/mL. After tannin extraction, higher EHI and lower LC90 were observed. In a larval development inhibition test, the LC90 of AE was 13.66mg/g of fecal culture. The highest dose of AE administered to mice (203.0mg/kg bw) was well tolerated, suggesting low toxicity. In vivo, AE was orally administered to lambs at 283mg/kg bw, and, at weeks one, two, and three post-treatment, the mean fecal egg count (FEC) was significantly lower than in untreated lambs (P<0.05). Blood parameters were normal and similar in untreated and treated sheep. For all lamb groups, the mean total serum protein was significantly higher at week two post-treatment than at other evaluated periods (P<0.05). Piptadenia viridiflora extracts had low condensed tannin content and exhibited high anthelminthic efficacy in vitro and significantly reduced FEC. Tannins were not shown to be the principal components affecting EHI, hence it is necessary to isolate and characterize the principal active P. viridiflora compounds, and to assess their possible synergism.
It is necessary to increase the rates of initial growth of pastures for use during the better planting period. Thus, two experiments were used to evaluate the effect of plant growth regulator (PGR; auxins, gibberellins and cytokinins) in seeds types (coated with polymer coating fungicide and conventional method) and nitrogen fertilization methods in Brachiaria decumbens cv. Basilisk on the germination, growth, development and physiological composition. From the regression estimates, lower levels of PGR (10.3; 12.8; 8.85 and 9.57 ml/kg for germination percentage, germination speed index, leaf and pseudostem, respectively) were recommended in coated seeds when compared to conventional method (untreated seeds, with polymer coating and fungicide). Leaf and pseudostem mass production had a significant interaction effect between seed type and the use of growth regulator. Coated seeds (with fungicide and polymers after scarification) had greater performance with absence or at lower levels (8.85 and 9.57 ml/kg seed) of growth regulators. This was not observed for conventional seeds, the higher doses (15.5 and 18.1 ml/kg) presented higher development for the same characteristics. In second experiment, rates of photoassimilate were increased by soil fertilization and use of PGRs. No influence of foliar fertilization was observed when used exclusively, but N‐fertilization multiple and soil promotes an increase in chlorophyll content and mass yield, respectively. The use of exogenous hormonal compounds acts on the organogenesis of plant tissues and increases the formation of plant tissues and acts in the promotion of germination and development of structures, making it a key tool in pasture establishment.
Dermacentor nitens tick is commonly found in the equine auditory canal, where it causes economic losses due to its direct damage, causing blood spoliation, stress, transmission of pathogens, and predisposition to myasis and secondary bacterial infection in its hosts. In this study we evaluated the effect of ethanolic extracts of Cerrado plants on biological parameters of engorged females of D. nitens. Ethanolic extracts were prepared from the leaves of Schinopsis brasiliensis, Piptadenia viridiflora, Ximenia americana, and Serjania lethalis at 25-150 mg mL. Groups of 10 engorged adult females were treated with these extracts and compared with a control containing distilled water and another control with organophosphate, using five replicates for each group. Compared with the control with water, S. lethalis and X. americana extracts at 100 and 150 mg mL significantly inhibited the posture ability. Differently, extracts of S. brasiliensis and P. viridiflora were the most effective in inhibiting larval hatching. Extracts of X. americana and P. viridiflora showed effective inhibition of reproductive parameters of the tick, presenting dose-dependent effect with IC 78.86 and 78.94 mg mL, respectively. Theses effective extracts contained low condensed tannin levels and their HPLC chromatograms revealed the presence of flavonoids. The efficacies of P. viridiflora and X. americana extracts were higher than 90% indicating that these extracts are promising as alternative agents for D. nitens control.
Background:Beef cattle is considered to be one of the most important economic activities, however, it presents problems in the production chain such as the occurrence of parasites that reduce the growth, performance, productivity and may cause mortalities occasionally. The chemical control is the most used alternative to reduce ectoparasites. Nevertheless, inappropriate management of insecticides has contributed to the selection of population resistant to the products available on the market. This paper aimed to evaluate the practices of management and the application of insecticides used to control horn flies in farms of dairy cattle in the North of the state of Minas Gerais. Materials, Methods & Results:It was visited 62 rural properties, which produce milk. Semi-structured questionnaires were applied in order to obtain information on the characteristics of the properties (location, size and type of the cattle), on the knowledge about the epidemiology of the horn flies, and on the practices adopted to the control of those parasites. The practices adopted include the moment of application of the insecticides, frequency of the cattle treatment, used products, method of application, number of animals treated, and choice and substitution criteria of insecticides. The data collected were tabulated in contingency tables, and they were analyzed using the chi-square test, considering a significance of 5%. The racial composition of the cattle in the farms was mainly mixed-race of unknown origin, representing 77% of the animals evaluated. In this research, it was reported a greater incidence of horn flies infestation on adult beef herd, and 23.6% of the producers reported occurrences of infestation in the whole herd, not differing by categories. The infestation peaks of the fly occurred from November to March. It was also found a greater frequency of pyrethroid use in the region (P < 0.001), where 43.1% of the producers used associations of pyrethroid or organophosphate to control the flies, high efficiency being reported. From the properties assessed, 92% presented inadequacy in the practices of control of horn flies, for instance, the lack of using cattle manure tank, the accumulation of open waste, the lack of rotation of insecticides, which can favor the selection of resistant flies. Discussion: In this paper, it was reported 77.19% of predominance of Haematobia irritans infestation from November to March mainly in animals with a higher percentage of European or mixed-race genetics. Such results corroborate with the literature, because it was verified the influence of race and hair color in the level of infestation in the animals, although, in the same race, each individual presents different susceptibilities. Taurine beef cattle are more susceptible to infestation by horn flies than zebu cattle. Thus, the lower the proportion of zebu cattle genetics in the herd, the greater the infestation. Taurine beef cattle are more infested because shows a greater number of sebaceous glands and greater concentration of testoster...
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