The potential environmental impact of pesticides removed from sprayers during cleaning

BACKGROUND: There is concern that pesticide residues on the external surfaces of sprayers could have an adverse impact on the environment if they are washed off, yet there is a need to remove these residues for health reasons. The aim of this study was to quantify pesticide residues contained in washings from cleaning discrete parts of a sprayer and to assess their likely environmental impact. RESULTS: The boom/rear of the sprayer and the spray tank accounted for 80% of the total pesticide load in the washings. Predicted environmental pesticide concentrations from sprayer washings were lower than predictions from the FOCUS surface water model for pesticides used under normal agricultural conditions, although for tebuconazole this difference was smaller than for the other compounds investigated. The field area over which the residues may need to be uniformly deposited to avoid overdosing during infield cleaning was typically less than 0.5 m(2), with a maximum value of 4 m(2). CONCLUSIONS: It is unlikely that infield cleaning will lead to overdosing. External residues are not insignificant, so any adverse impact on the environment must be mitigated. Appropriate measures include cleaning in the field away from surface waters and other sensitive areas, and cleaning machines over bunded areas or similar.     

A case of methicillin-resistant Staphylococcus pseudintermedius (MRSP) pyoderma in a Labrador retriever dog

An 8-year-old, neutered male Labrador retriever dog with generalized pruritis had a history of recurring atopic dermatitis and superficial pyoderma. Cocci and yeast were found on cytology and methicillin-resistant Staphylococcus pseudintermedius was cultured. A regimen of marbofloxacin, dexamethasone, ketoconazole, and cyclosporine in addition to bathing with 2% chlorhexidine shampoo resulted in marked improvement.     

Transient Fanconi syndrome in Quarter horses

Two Quarter horses with weight loss had glucosuria, euglycemia, and a mild metabolic acidosis suggesting a proximal renal tubular defect. Further testing revealed transient generalized aminoaciduria, lactic aciduria, and glucosuria, indicating Fanconi syndrome. Both horses recovered with supportive therapy. This is the first report of acquired Fanconi syndrome in horses.     

Evaluation of steroidogenic capacity after follicle stimulating hormone stimulation in bovine granulosa cells of Revalor 200? implanted heifers

Background

Heifers not used as breeding stock are often implanted with steroids to increase growth efficiency thereby altering hormone profiles and potentially changing the environment in which ovarian follicles develop. Because bovine granulosa cell culture is a commonly used technique and often bovine ovaries are collected from abattoirs with no record of implant status, the objective of this study was to determine if the presence of an implant during bovine granulosa cell development impacts follicle stimulating hormone-regulated steroidogenic enzyme expression. Paired ovaries were collected from 16 feedlot heifers subjected to 1 of 3 treatments: non-implanted (n = 5), Revalor 200 for 28 d (n = 5), or Revalor 200 for 84 d (n = 6). Small follicle (1 to 5 mm) granulosa cells were isolated from each pair and incubated with phosphate buffered saline (n = 16) or 100 ng/mL follicle stimulating hormone (n = 16) for 24 h.

Results

Granulosa cells of implanted heifers treated with follicle stimulating hormone produced medium concentrations of progesterone similar (P = 0.22) to non-implanted heifers, while medium estradiol concentrations were increased (P < 0.10) at 28 and 84 d compared to non-implanted heifers indicating efficacy of treatment. Additionally, real-time PCR analysis in response to follicle stimulating hormone treatment demonstrated a decrease in steroidogenic acute regulatory protein (P = 0.05) mRNA expression in heifers implanted for 84 d and an increase in P450 side chain cleavage mRNA in granulosa cells of heifers implanted for 28 (P < 0.10) or 84 d (P < 0.05) compared to non-implanted females. However, no difference in expression of 3-beta-hydroxysteroid dehydrogenase (P = 0.57) and aromatase (P = 0.23) were demonstrated in implanted or non-implanted heifers.

Conclusions

These results indicate follicles which develop in the presence of high concentrations of androgenic and estrogenic steroids via an implant tend to demonstrate an altered capacity to respond to follicle stimulating hormone stimulation. Thus, efforts should be made to avoid the use of implanted heifers to study steroidogenesis in small follicle granulosa cell culture systems.     

Maximizing lobster, Homarus gammarus (L.), egg and larval viability

The viability of batches of larvae reared to produce lobsters, Homarus gammarus (L.), for stock-supplementation experiments varied widely and rendered the timing and numbers of juveniles available for release unpredictable. Egg lipid reserves, time of hatching, exposure to low salinity during incubation and the influence of feeding regimes on water quality during larval culture were among the factors judged most likely to have affected viability. There was considerable variation in the lipid content of eggs from different females captured in 1989 and 1990. The proportion of lipid in eggs from females caught in 1990 was higher (10-20%) than that in eggs from females caught in 1989 (6-11%). The fatty acid content of eggs declined 72-80% during development although the overall proportions of fatty acids remained similar. Analysis of eggs and larvae from a single brood showed that rapidly developing eggs and the larvae that hatched from them contained greater triacylglyceride lipid reserves (by 49% and 15% respectively) than those which developed more slowly and hatched later. Exposure to reduced salinity (below 29 psu) prolonged development (by 30%), increased losses (to > 50%) and reduced the ratio of n-3:n-6 fatty acids (from 35-48 to 18-29) of eggs being incubated by captive, wild-caught, female lobsters. Larvae hatching from eggs held in reduced salinity (23 psu) survived less well (3% compared with 15%) than those incubated in sea water of 29 psu. The rate and degree to which fouling organisms became attached to larvae was related to feeding regime but not to development rate. A diet of mysids supplemented with mussel produced most fouling, generally poorer growth and a higher incidence of moulting abnormalities than a diet of mysids supplemented with Artemia nauplii. Among larvae fed Artemia, those developing early were significantly larger at instar 4 than late developers (56.4 mg cf. 49.8 mg, P < 0.05), but such differences in weight were not maintained by juveniles during the following 31 days of culture. The ecological and aquacultural implications of the results are discussed.     

The breeding and growth of Penaeus merguiensis de Man in laboratory recirculation systems

Penaeus merguiensis was cultured through three generations in laboratory recirculation systems. Populations of 24–76 prawns produced, on average, 2–15 batches of 44 000 eggs per month throughout a 16-month period. Survival to metamorphosis was over 50% and post-larvae reached a size (0.15 g live weight) suitable for stocking in “grow-out” tanks 50–60 days after being spawned. In the subsequent 16 weeks prawns reached 5–7 g live weight with 24–58% survival.