Residues In Dung Research Articles

Eprinomectin from a sustained release formulation adversely affected dung breeding insects.

The insecticidal activity of parasiticide residues in dung of cattle treated with a sustained release eprinomectin formulation was examined, and an improved eprinomectin dung residue extraction method is presented. Emergent insect abundance and richness were significantly reduced in all post-treatment intervals (7, 14, 28, 56, 84, 112, and 140 d), relative to pre-treatment. Emergent insect diversity was reduced for between 84 and 112 d post-treatment. Collembola were not affected by residues. Chemical analyses subsequently documented residues of eprinomectin in dung of each collection period post-treatment at levels expected based on previously reported excretion profiles for this product. Cattle subcutaneously injected with this product excreted residues that reduced dung-breeding insect emergence for 5 mo post-treatment. The consequences of these long-term non-target effects to pasture ecosystems are not known.

Modelling the impact of targeted anthelmintic treatment of cattle on dung fauna

The insecticidal properties of many anthelmintics pose a risk to dung fauna through the effects of drug residues in dung on the activity, oviposition and development of dung-dwelling invertebrates. Reductions in dung fauna numbers can inhibit dung degradation, which may impact biodiversity and nutrient cycling on farms. A simulation model was created to predict the impact of antiparasitic drugs on cattle dung fauna, and calibrated using published data on the dung-breeding fly Scathophaga stercoraria. This model was then tested under different effective dung drug concentrations (EC) and proportions of treated cattle (PT) to determine the impact under different application regimens. EC accounted for 12.9% of the observed variation in S. stercoraria population size, whilst PT accounted for 54.9%. The model outputs indicate that the tendency within veterinary medicine for targeted selective treatments (TST), in order to attenuate selection for drug resistance in parasite populations, will decrease the negative impacts of treatments on dung fauna populations by providing population refugia. This provides novel evidence for the benefits of TST regimens on local food webs, relative to whole-herd treatments. The model outputs were used to create a risk graph for stakeholders to use to estimate risk of anthelminthic toxicity to dung fauna.

Analysis and dissipation of the antiparasitic agent ivermectin in cattle dung under different field conditions.

Cattle treated with the veterinary parasiticide ivermectin fecally excrete residues. The authors report the exposition and dissipation characteristics of these residues in dung of ivermectin-treated cattle and in soil beneath this dung on pastures in Canada, France, Switzerland, and The Netherlands. Residues were quantified for dung collected from cattle after 3 d, 7 d, 14 d, and 28 d posttreatment and subsequently exposed in the field for up to 13 mo. The authors optimized a high-performance liquid chromatography-fluorescence detection method to detect ivermectin residues in dung and soil matrices. They showed that a solid phase extraction and purification step generally can be eliminated to reduce the time and cost of these analyses. They also found that the addition of water to relatively dry samples improves the extraction efficiency of residues. They then analyzed the field samples to document differences in ivermectin dissipation in cattle dung among sites, with 50% dissipation times of up to 32 d and 90% dissipation times >396 d. They further showed that the dissipation characteristics of residues are comparable between dung of ivermectin-treated cattle and dung to which ivermectin has been added directly. Lastly, they report the first use of a desorption electrospray ionization-high-resolution-mass spectrometric method to detect residues of metabolites in a dung matrix. Environ Toxicol Chem 2016;35:1924-1933. © 2016 SETAC.

Validation of a standard field test method in four countries to assess the toxicity of residues in dung of cattle treated with veterinary medical products.

Registration of veterinary medical products includes the provision that field tests may be required to assess potential nontarget effects associated with the excretion of product residues in dung of treated livestock (phase II, tier B testing). However, regulatory agencies provide no guidance on the format of these tests. In the present study, the authors report on the development of a standardized field test method designed to serve as a tier B test. Dung was collected from cattle before and up to 2 mo after treatment with a topical application of a test compound (ivermectin). Pats formed of dung from the different treatments were placed concurrently in the field to be colonized by insects. The abundance, richness, and diversity of insects developing from egg to adult in these pats were compared across treatments using analysis of variance tests. Regression analyses were used to regress abundance, richness, and diversity against residue concentrations in each treatment. Results of the regression were used to estimate mean lethal concentration (LC50) values. The robustness of the method and the repeatability of its findings were assessed concurrently in 4 countries (Canada, France, Switzerland, and The Netherlands) in climatically diverse ecoregions. Results were generally consistent across countries, and support the method's formal adoption by the European Union to assess the effects of veterinary medical product residues on the composition and diversity of insects in dung of treated livestock. Environ Toxicol Chem 2016;35:1934-1946. © 2015 Crown in the right of Canada. Published by Wiley Periodicals Inc., on behalf of SETAC.

Standardized laboratory tests with 21 species of temperate and tropical sepsid flies confirm their suitability as bioassays of pharmaceutical residues (ivermectin) in cattle dung

Veterinary pharmaceuticals excreted in the dung of treated livestock can have strong non-target effects on the dung organism community. We report results of ecotoxicological tests with ivermectin for 21 species of temperate (Europe, North America) and tropical (Asia, Central America) black scavenger flies (Diptera: Sepsidae), using standardized methods developed previously for the yellow dung fly and the face fly. Our study documents great variation in ivermectin sensitivity of more than two orders of magnitude among species and even populations within species: estimated lethal effect concentrations LC50 (at which 50% of the flies died) ranged from 0.05 to 18.55μg/kg dung fresh weight (equivalent to 0.33–132.22μg/kg dung dry weight). We also show that controlled laboratory tests can—within reasonable limits—be extended to the field or to laboratory settings without climate control, as obtained LC50 were roughly similar. In addition to lethal effects, our study revealed relevant sub-lethal effects at lower ivermectin concentrations in terms of prolonged development, smaller body size and reduced juvenile growth rate. Finally, oviposition choice experiments showed that females generally do not discriminate against dung containing ivermectin residues. We conclude that sepsid flies are well suited test organisms for pharmaceutical residues in the dung of livestock due to their ease and speed of rearing and handling, particularly in the tropics, where high-tech laboratory equipment is often not available.

Aggregation in cattle dung-colonizing insect communities

Background Ruminant dung is a highly ephemeral, patchily distributed resource, which is utilized by a diverse community of invertebrate species. This ecologically important community may be affected adversely by insecticide and endectocide residues in the faeces of treated cattle. The aim of the present work was to quantify the aggregation of the insects colonising cow-dung in cattle pastures and test the hypothesis that the dung-pat community assemblage observed is the result of stochastic colonization events. Methods Fresh dung from dairy cattle was used to construct arrays of standardised, 1.5kg, artificial cow pats in cattle pastures. Batches of ten pats were placed out each week for 24 weeks, between May and October in 2001. Pats were left exposed in the field for seven days, to allow colonisation. Pats were then brought back to the laboratory and insect colonizers were collected and identified. Results Individual pats contained on average, only half the number of insect taxa present in an entire batch put out at any one time. Among six representative taxa of Diptera and four of Coleoptera, significant levels of intraspecific aggregation were observed in all but one (Mesembina meridiana), with the abundance of most taxa within pats approximating a negative binomial distribution. A simulation analysis was used to show that the observed relative frequency of taxa within pats does not differ from that expected by chance if colonisation is a random binomial event in which each species colonises a pat independently of all other species. Conclusion The highly aggregated distributions observed in this study highlight the need for relatively large sample sizes when attempting to assess the abundance and distribution of individual taxa in cow dung. In addition, the results suggest that the aggregated populations of even highly abundant insects will be more susceptible to the deleterious effects of insecticidal residues in dung than if they were evenly distributed, if by chance they colonize a pat containing insecticidal residues from a recently treated animal.

Field-scale dispersal ofAphodiusdung beetles (Coleoptera: Scarabaeidae) in response to avermectin treatments on pastured cattle

Very few studies have examined, at the field scale, the potential for faecal residues in the dung of avermectin-treated cattle to affect dung-breeding insects. The current study examined populations of dung beetles (Scarabaeidae: Aphodius) using pitfall traps baited with dung from untreated cattle on 26 fields across eight farms in southwest Scotland. The fields were grazed either by untreated cattle or by cattle treated with an avermectin product, i.e. doramectin or ivermectin. During the two-year study, significantly more beetles were trapped in fields grazed by treated cattle (n=9377 beetles) than in fields where cattle remained untreated (n=2483 beetles). Additional trials showed that beetles preferentially colonised dung of untreated versus doramectin-treated cattle. This may explain the higher captures of beetles in traps baited with dung of untreated cattle, which were located in fields of treated cattle. Given that Aphodius beetles avoided dung of treated cattle in the current study, the potential harmful effects of avermectin residues in cattle dung could be reduced through livestock management practices that maximise the availability of dung from untreated livestock in areas where avermectins are being used.

Does Doramectin Use on Cattle Indirectly Affect the Endangered Burrowing Owl

Doramectin is one of several endectocide compounds widely used to treat nematode and arthropod pests affecting cattle. Insecticidal residues in dung of endectocide-treated cattle can reduce numbers of dung-breeding insects. Concerns have been raised that use of endectocides may adversely affect birds that rely on dung-breeding insects as food. However, these concerns have not been specifically addressed in previous studies. We performed two studies to collectively assess whether doramectin adversely affects burrowing owls (Athene cunicularia Molina), which are listed as ‘‘Endangered’’ in Canada. In the first study, insect emergence was monitored from dung of cattle treated with a recommended topical dose of doramectin. Experiments replicated in each of 3 yr showed residues reduce the number of insects developing in dung of cattle treated up to 16 wk previously. In the second study, we identified prey items from regurgitated pellets collected at 206 burrowing owl nests in southern Alberta and Saskatchewan, Canada. A total of 50 213 prey items were identified, of which 90% were invertebrates. Beetles (Coleoptera) comprised 54% of the total prey items, followed next in abundance by grasshoppers (Acrididae, 20%) and crickets (Gryllidae, 16%). Of the beetles, 1 381 specimens were identified as breeding in dung (mainly species of Aphodius, Canthon, Onthophagus). The dung beetles comprised an estimated 2.8% of the total prey items or 0.1% of total prey biomass. Results of the first study validate initial concerns that doramectin use can reduce numbers of insects breeding in dung of treated cattle. Results of the second study show reliance of burrowing owls on dung beetles is sufficiently low that use of doramectin on cattle is unlikely to appreciably affect the food supply of co-occurring burrowing owls.

Effects of avermectin residues in cattle dung on yellow dung flyScathophaga stercoraria(Diptera: Scathophagidae) populations in grazed pastures

The effects of avermectin exposure on natural populations of the yellow dung fly, Scathophaga stercoraria Linnaeus, were investigated at the field scale on farms in south-west Scotland. Pastures forming the focus of the study were grazed with either untreated cattle or cattle receiving standard, manufacturer-recommended treatment regimes of an avermectin product. Flies were sampled between April and July in 2002 and 2003 using dung-baited pitfall traps. Abundance and wing asymmetry in S. stercoraria populations were examined in relation to a range of environmental and management variables (including avermectin exposure, pasture management intensity, weather and season). Data used for abundance analyses were collected in fields where treated cattle had been dosed with either doramectin or ivermectin, while the data for the asymmetry analyses were from a subset of fields where treated cattle had been dosed with doramectin only. While abundance of S. stercoraria varied significantly between years and with season, there was no difference in their abundance between fields grazed by avermectin-treated or untreated cattle. Asymmetry was significantly higher in fly populations in fields grazed by doramectin-treated cattle, suggesting that exposure to doramectin during development could have imposed some degree of environmental stress. While these results suggest that exposure to doramectin residues in dung on grazed pastures may have sublethal effects on the insects developing in that dung, there was no evident avermectin effect on the abundance of adult S. stercoraria occurring in the pastures.

Reproduction of the dung beetle ( Copris tripartitus) in the dung of cattle treated with cis-cypermethrin and chlorpyrifos

Fresh dung was collected from untreated cattle and cattle dosed with a spray-on formulation of high cis-cypermethrin and chlorpyrifos (2.1 g/cow), on days 1, 3, 5 and 7 post-treatment. The survival and reproduction of the dung beetle Copris tripartitus Waterhouse, when given this dung was assessed. Residues of high cis-cypermethrin and chlorpyrifos in dung collected 1 day after treatment were sufficient to inhibit oviposition by female C. tripartitus. However, there was no significant effect on egg-laying in dung collected at days 3, 5 or 7 days post-treatment. In a second generation of C. tripartitus, derived from beetles fed the dung from treated animals, residues in dung collected both 1 and 3 days after treatment were sufficient to inhibit oviposition, and residues in dung collected 1 day after treatment inhibited dung consumption by newly emerged adults of C. tripartitus. It is concluded that dung voided by cattle treated with a spray-on formulation of high cis-cypermethrin and chlorpyrifos have toxic lethal effects for 1 day post-treatment and sub-lethal toxic effects on ovarian condition and brood-ball production in dung voided at 1 and 3 days post-treatment. The potential ecotoxic effects of these compounds are discussed in terms of dung beetle activity and strategies for parasite control of cattle in the Korean environment.

Survival and reproduction ofEuoniticellus intermedius(Coleoptera: Scarabaeidae) in dung following application of cypermethrin and flumethrin pour-ons to cattle

AbstractCattle were treated with cypermethrin and flumethrin pour-ons to determine possible adverse effects of residues in dung on the survival, fecundity and fertility ofEuoniticellus intermedius(Reiche). Dung from both cypermethrin- and flumethrin-treated cattle was collected 1, 2, 3, 5, 7, 14, 21 and 28 days after treatment, with an untreated control for each. Mortality of adultE.intermediusexposed to dung collected from cypermethrin-treated cattle two to seven days after treatment ranged between 80% and 100%. Cypermethrin had no effect on adult and immature survival or on fecundity and fertility ofE.intermediusexposed to dung collected 1, 14, 21 and 28 days after treatment. Dung collected from flumethrin-treated cattle had no apparent effect on adult survival, egg production, immature survival, adult emergence, fecundity and fertility ofE.intermedius, except at seven days after treatment, when fewer brood balls were produced and consequently fewer adults emerged from dung from treated animals compared with the control.

Effects of ivermectin residues in sheep dung on the development and survival of the bushfly, Musca vetustissima Walker and a scarabaeine dung beetle, Euoniticellus fulvus Goeze

Dung produced by sheep for up to 1 week post-treatment (drenching) with ivermectin caused significant mortality to newly emerged larvae of the bushfly Musca vetustissima. Dung from sheep drenched with a mixture of levamisole and oxfendazole also resulted in larval mortality, but here the effect was limited to the first 48 h after treatment. Flies reared through to the adult stage on dung collected up to 32 days post-drenching were tested for evidence of fluctuating asymmetry, which is an indicator of developmental stress. None was found for either drench treatment, although there was evidence that ivermectin residues directly affected wing size. The introduced dung beetle, Euoniticellus fulvus was also found to be sensitive to ivermectin residues in sheep dung. Dung produced during the first day after drenching caused mortality among newly emerged beetles and delayed the reproductive development of survivors. However, beetles in which ovarian development was impaired regained their reproductive capacity following transfer to non-toxic dung. Day 1 dung caused no mortality among sexually mature beetles, although there was a significant reduction in their fecundity. Dung collected from 2 to 10 days post-drenching had no detectable effects on either the survival or reproductive development of adult beetles, regardless of age. Residues in dung collected 1–2 days post-drenching caused 100% mortality in beetle larvae, but by Day 5 there was no evidence of acute toxicity. These findings indicate that insects feeding on the dung of ivermectin-treated sheep display adverse effects similar in range to those reported for cattle dung. However, their duration is much more transient, owing probably to differences in drug formulation and route of administration.

Effects of avermectin residues in cattle dung on dung beetle (Coleoptera: Scarabaeidae) reproduction and survival

Scarabaeine dung beetles feeding on dung from cattle treated with an injection of avermectin at a therapeutic dose to control internal parasites, show larval mortality, mortality of immature adults, reduced egg production, and inhibited ovariole development for periods of 1–4 weeks following treatment. In winter rainfall regions of Australia, feeding by newly emerged adults of an introduced species, Onthophagus binodis, resulted in shredding of cattle dung between December and May. Production of brood masses and eggs resulted in dung being buried from September to November. Feeding by newly emerged adults of a native species, Onthophagus ferox, resulted in dung being buried in May and June, and production of brood masses for breeding resulted in dung burial between September and November. There are thus 2–6 months of the year when injection of cattle with avermectin would affect mortality of newly emerged beetles, and 3 months of the year when avermectin treatment of cattle would affect dung beetle oviposition or larval survival. Beetles were attracted to fresh dung for 2–4 days, and most had left the pad within a week. There are no data to indicate the effects of avermectin residues in dung on dung beetle populations and on beetle fitness. Tests should be done to determine if avermectins in slow release devices have a greater effect on dung beetles than injections, and to determine what effects both have on dung beetle populations.