Dung avoidance behavior in Crioula Lanada lambs naturally infected with gastrointestinal nematodes in a rotational pasture system.

This study aimed to evaluate foraging distance (FD) from the dung, parasitological and physiological factors in 18 Crioula Lanada lambs naturally infected by nematodes with three infection levels (IL) in a Voisin Grazing System. In the pre-experimental phase animal feces collection, deworming, observer training, animal adaptation and dung demarcation were carried out; in the experimental phase, grazing distance, feces, pasture and blood sampling. An initial exploratory analysis was carried out (Kruskal-Wallis test). Fixed predictors were selected with a cumulative logit regression model; an ordinal logistic regression mixed model identified influencing factors of ordinal responses for (i) FD, (ii) infective larvae quantity (L3). Animals approached the dung when the radiation or temperature were more intense (P < 0.05). Paddock entry/exit, IgG and L3 influenced FD over time (P < 0.05). L3, in turn, was influenced by IL, FEC and corpuscular volume (CV). In the High IL group, FD varied between 60-100 cm. Greater L3 and FEC were found in the High and Low IL from the 4th week (P < 0.05). Naturally infected Crioula Lanada lambs increased the distance from the dung, which was not related to IL but to the dynamics of solar radiation and parasitological and immunological factors.

Dung avoidance behavior in Crioula Lanada lambs naturally infected with gastrointestinal nematodes in a rotational pasture system / Comportamento de afastamento do bolo fecal em cordeiros Crioula Lanada naturalmente infectados com nematoides gastrintestinais em sistema de pastoreio rotacionado

Abstract This study aimed to evaluate foraging distance (FD) from the dung, parasitological and physiological factors in 18 Crioula Lanada lambs naturally infected by nematodes with three infection levels (IL) in a Voisin Grazing System. In the pre-experimental phase animal feces collection, deworming, observer training, animal adaptation and dung demarcation were carried out; in the experimental phase, grazing distance, feces, pasture and blood sampling. An initial exploratory analysis was carried out (Kruskal-Wallis test). Fixed predictors were selected with a cumulative logit regression model; an ordinal logistic regression mixed model identified influencing factors of ordinal responses for (i) FD, (ii) infective larvae quantity (L3). Animals approached the dung when the radiation or temperature were more intense (P < 0.05). Paddock entry/exit, IgG and L3 influenced FD over time (P < 0.05). L3, in turn, was influenced by IL, FEC and corpuscular volume (CV). In the High IL group, FD varied between 60-100 cm. Greater L3 and FEC were found in the High and Low IL from the 4th week (P < 0.05). Naturally infected Crioula Lanada lambs increased the distance from the dung, which was not related to IL but to the dynamics of solar radiation and parasitological and immunological factors.

Resumo O objetivo deste estudo foi avaliar a distância de forrageamento do bolo fecal (DF), fatores parasitológicos e fisiológicos em 18 cordeiros Crioula Lanada, naturalmente infectados por nematoides com três níveis de infecção (NI) em sistema Pastoreio Racional Voisin (PRV). Na fase pré-experimental, houve coleta de fezes dos animais, vermifugação, treinamento de observadores, adaptação dos animais e demarcação do bolo fecal; na fase experimental, distância, fezes, pastagem e sangue. Um modelo de regressão "logit" cumulativa selecionou preditores fixos; um modelo misto de regressão logística ordinal identificou fatores influenciadores das respostas ordinais para (i) DF (ii) quantidade de larva infectante (L3). Os cordeiros se aproximaram do bolo fecal quando a radiação ou temperatura foram mais intensas (P < 0,05). A entrada e a saída dos piquetes, a ingestão de L3 e IgG influenciaram DF (P < 0,05). L3 foi influenciada por NI, OPG e volume corpuscular. O grupo NI Alta variou a distância entre 60-100 cm. Maior L3 e a FEC foram encontrados nos grupos NI Alta e Baixa a partir da 4ª semana (P < 0,05). Cordeiros Crioula Lanada, naturalmente infectados, aumentaram a DF, sem relação com nível, de infecção, mas com a dinâmica da radiação solar e dos fatores parasitológicos e imunológicos.

Data of insecticide action of a nanoemulsion of Citronella essential oil on Cochliomyia hominivorax blowfly.

Cochliomyia hominivorax is the dipteran that causes the worst and most serious types of myiasis in animals and humans in the Americas. The data described here show the effects of a commercial product formulated on the basis of citronella essential oil nanoemulsified (Nano Citronela Plus®) directly on eggs, first, second and third stage larvae of the C. hominivorax blowfly, in addition to the indirect effect on the oviposition of adult flies. These data make up the gross base that was used in the preparation of the article "Repellent, ovicidal, larvicidal and adulticidal action of a nanoemulsion of Citronella essential oil (Cymbopogon winterianus) on Cochliomyia hominivorax (Diptera: Calliphoridae)" Bricarello et al., 2021. Counting data of larvae, eggs and adult flies live and dead after contact with the product, data on weighing and counting of eggs from the repellency test are available, as well as photos of cuticular changes that occurred in the larvae and malformations observed after contact with Nano Citronela Plus®.

Peripartum Phenomenon in Crioula Lanada Sheep Susceptible and Resistant to Gastrointestinal Nematodes.

This study aimed at evaluating parasitological and blood variables in native breed Crioula Lanada sheep belonging to the same herd, to identify and compare susceptible or resistant individuals to gastrointestinal nematodes during gestation and lactation phases. For this purpose, 18 Crioula sheep were used within 2 years of evaluation, in which blood and feces samples and weight of the animals were taken from their 4th month of gestation until the weaning of their lambs, in the 4th month postpartum. Feces samples were used for counting eggs per gram of feces (EPG) and, thus, to identify 12 resistant ewes (EPG < 1,000) and 6 susceptible (EPG > 1,000) to gastrointestinal nematodes. The identification of infective larvae was also performed. Blood was used for analysis of packed cell volume (PCV), eosinophil count, total plasma protein, and immunoglobulin G level against Haemonchus contortus infective larvae. The Kruskal-Wallis non-parametric comparison test was used to evaluate the differences between days of parturition and linear mixed-effects model using package lme4 in R to evaluate the groups. The main parasite species observed in the feces samples were Haemonchus, Trichostrongylus, Oesophagostomum, Ostertagia, and Cooperia in similar proportions in both groups. Susceptible ewes presented peaks of EPG at the beginning of lactation and lower PCV values throughout the study. No difference between groups was observed concerning other blood variables or body weight, but some changes were observed along with the gestation and lactation phases within each group. The physiological response of sheep to nematode infection is a useful tool to identify the most susceptible individuals within the same breed and herd and to select the most genetically resistant individuals.

Effect of Homeopathic Medicines and a Nosode on Larvae of Cochliomyia hominivorax (Diptera: Calliphoridae).

BACKGROUND: Cochliomyia hominivorax is the major fly causing primary myiasis in livestock animals in Brazil; its larvae develop in the host's living tissues, causing mutilations, which can even lead to death. In conventional treatments of myiasis, chemo-synthetic insecticides have been employed directly on larvae present in the wounds. Homeopathy may represent a healthy and sustainable alternative both to prevent and to treat myiasis in animals and humans. The current study evaluated how the emergence of adult insects is affected by the use of the homeopathic medicines Sulfur 12cH and Pyrogenium 12cH, and the nosode produced from C. hominivorax larvae at potencies 8cH and 12cH, on third-stage larvae of a C. hominivorax colony. MATERIALS AND METHODS: The homeopathic medicines and the nosodes were produced according to the Brazilian Homeopathic Pharmacopoeia. Control groups were distilled water, alcohol, no substance, and the organophosphate insecticide trichlorfon. For each group, 10 replicates were performed. Emergence rate of adult insects was evaluated by descriptive statistics followed by analysis of variance. Homogeneity of variances was verified by F-test and group means were compared with Tukey's test. RESULTS: Mortality rates in control groups were 2.7% for 30% (v/v) alcohol, 4.3% for distilled water, 3.2% for no substance (p > 0.05). In the trichlorfon group, the mortality rate of larvae was 90.8%. For Sulfur 12cH, the mortality of larvae was 94.6%, and for Pyrogenium 12cH it was 98.6%. The latter three means were not statistically different from each other or from the mean found for the trichlorfon group. The mortality rates of larvae were 61.3% and 66.6% for nosode C. hominivorax 8cH and 12cH, respectively (p > 0.05). CONCLUSIONS: Results suggest that homeopathy could be used therapeutically to prevent and treat animals and humans with myiasis caused by C. hominivorax.