Global genomic methylation related to the degree of parasitism in cattle.

The objective of the present study was to characterize a herd of 72 ½ Angus × ½ Nellore heifers, identify the resistant, resilient and susceptible animals to parasites, relate the overall DNA methylation of these animals with the degree of parasitism, evaluated by the egg count per gram of feces (EPG), Haematobia irritans count (horn fly) and Rhipicephalus microplus count (bovine tick). The experiment was carried out in a completely randomized design, containing 72 treatments, with each animal considered a treatment, and 11 repetitions, with each collection within a year considered a repetition. The data obtained from the counts of the evaluated parasites were subjected to statistical analysis using the SISVAR program, to classify heifers according to the degree of parasitism in low (resistant), intermediary (resilient) and high (susceptible) parasite load for infection by nematodes, infestation by ticks and flies. Addition the animals in these three groups, by hierarchical grouping using the GENES program, heifers were classified as to the degree of parasitism by the three parasites along with the DNA methylation content of the animals in each group. A negative relationship was observed between resistance and methylated DNA content in both classifications, with the resistant, resilient, and susceptible animals showing the highest, intermediate, and lowest methylated DNA quantifications, respectively. Thus, the methodologies used herein enabled the classification of 72 heifers according to the degree of collective infection by gastrointestinal nematodes and infestation by ticks and horn flies, thereby establishing a link between the degree of parasitic resistance in cattle and the global methylated DNA quantification.

Eficacy of ivermectin, moxidectin and febendazole in equine in Brazil.

The objectives of the present study were to evaluate the efficacy of three anthelmintic drugs, i.e. fenbendazole, ivermectin and moxidectin; to determine the genera and species of the most abundant strongyles; and to investigate parasite control measures used in herds of horses in the western region of the state of São Paulo, Brazil. This study was onducted between February and December 2013 on 10 farms in this region. Coprological evaluations were conducted for counting the numbers of eggs per gram of feces (EPG) and coprocultures were made in order to identify third-stage larvae (L3) of strongyles. Parasite control measures were investigated by surveying each farm's management and characteristics. A fecal egg count reduction test (FECRT) was used to determine the anthelmintic efficacy based on EPG count results before and after treatment. The FECRT showed that anthelmintic resistance to fenbendazole was present and that ivermectin and moxidectin had high effectiveness in the western region of the state of São Paulo. Identification of L3 revealed that there was high prevalence of cyathostomins among strongyle larvae. The highest prevalence of Strongylus vulgaris occurred on farms where the intervals between deworming were long. The questionnaire applied showed that ivermectin was the drug most used among these farmers.

Parasitism in Angus x Nellore heifers in a silvopastoral system.

The influence of shade in the silvopastoral system on the performance and degree of parasitism by endo- and ectoparasites in Angus x Nellore heifers was assessed. The experiment was conducted with 72 heifers, with an initial mean weight of 276 ± 5.67 kg and 9 months of age, in a total area of 25 ha, divided into 12 paddocks, with three treatments and four replicates. The experimental design was a randomized complete block design, to evaluate the conventional grazing system (CGS) without shade and silvopastoral systems with simple line (SPS1) or triple lines (SPS3) of eucalyptus. The evaluations were carried out every 28 days, from June 2017 to April 2018. During the trial, the number of eggs per gram of feces (EPG) presented a gradual increase in the three systems. Differences (P < 0.05) in the variables analyzed were recorded only in two occasions: the CGS group EPG mean ± standard error (1269 ± 105) was higher than the SPS1 group mean (402 ± 129 EPG) in March, and tick average of the CGS group (13 ± 2.7) was lower than the SPS3 (32 ± 5.3) in October. There were no significant differences (P ≥ 0.05) between groups in relation to horn fly counts, the numbers of infective nematode larvae on pasture, hematological variables, and weight gain. It was concluded that in comparison with the CGS system, the shading in the SPS1 and SPS3 systems did not have any major influence on the degree of parasitism or in the performance of the heifers.