Bilateral anterior segment dysgenesis in a 7-week-old domestic shorthaired cat

A 7-week-old, intact, female domestic shorthaired cat was presented to the Atlantic Veterinary College (AVC) Ophthalmology service for a 1-week history of buphthalmia in the left eye and bilateral elevated intraocular pressures. Ocular examination revealed bilateral non-visual glaucomatous eyes. Bilateral enucleations were performed without complications and histopathology revealed anterior segment dysgenesis of varying degrees in both eyes.Key clinical message:Anterior segment dysgenesis is a developmental condition that can result in primary congenital glaucoma for which the best course of treatment is enucleation.     

A critical role of interleukin-10 in the response of bovine macrophages to infection by Mycobacterium avium subsp paratuberculosis

OBJECTIVES: To evaluate the role of interleukin (IL)-10 in the inability of monocyte-derived bovine macrophages to kill Mycobacterium avium subsp paratuberculosis organisms in vitro. SAMPLE POPULATION: Monocytes were obtained from healthy adult Holstein dairy cows that had negative results when tested for infection with M avium subsp paratuberculosis. PROCEDURE: Monocyte-derived macrophages were incubated with M avium subsp paratuberculosis for 2, 6, 24, 72, or 96 hours with or without addition of saturating concentrations of a goat anti-human IL-10 that has been documented to neutralize bovine IL-10 activity. Variables assessed included ingestion and killing of M avium subsp paratuberculosis; expression of tumor necrosis factor (TNF)-alpha, IL-12, IL-8, major histocompatability (MHC) class II, vacuolar H+ ATPase, and B cell CLL/lymphoma 2 (BCL-2); production of nitric oxide; acidification of phagosomes; and apoptosis of macrophages. RESULTS: Neutralization of IL-10 enabled macrophages to kill 57% of M avium subsp paratuberculosis organisms within 96 hours. It also resulted in an increase in expression of TNF-alpha, IL-12, IL-8, MHC class II, and vacuolar H+ ATPase; decrease in expression of BCL-2; increase in acidification of phagosomes; apoptosis of macrophages; and production of nitric oxide. CONCLUSIONS AND CLINICAL RELEVANCE: The capacity of M avium subsp paratuberculosis to induce IL-10 expression may be a major determinant of virulence for this organism.     

Effects of chlorpyrifos in freshwater model ecosystems: the influence of experimental conditions on ecotoxicological thresholds

Three experiments were conducted to determine the impact of the insecticide chlorpyrifos (single applications of 0.01 to 10 microg AI litre(-1)) in plankton-dominated nutrient-rich microcosms. The microcosms (water volume approximately 14 litres) were established in the laboratory under temperature, light regimes and nutrient levels that simulated cool 'temperate' and warm 'Mediterranean' environmental conditions. The fate of chlorpyrifos in the water column was monitored and the effects on zooplankton, phytoplankton and community metabolism were followed for 4 or 5 weeks. The mean half-life (t1/2) of chlorpyrifos in the water of the test systems was 45 h under 'temperate' conditions and about 30 h under 'Mediterranean' environmental conditions. Microcrustaceans (cladocerans and copepod nauplii) were amongst the most sensitive organisms. All three experiments yielded community NOEC (no observed effect concentrations) of 0.1 microg AI litre(-1), similar to those derived from more complex outdoor studies. Above this threshold level, responses and effect chains, and time spans for recovery, differed between the experiments. For example, algal blooms as an indirect effect from the impact of exposure on grazing organisms were only observed under the 'Mediterranean' experimental conditions. The relatively simple indoor test system seems to be sufficient to provide estimates of safe threshold levels for the acute insecticidal effects of low-persistence compounds such as chlorpyrifos. The robustness of the community NOEC indicates that this threshold level is likely to be representative for many freshwater systems.     

Biofilm bacteria: formation and comparative susceptibility to antibiotics

The Calgary Biofilm Device (CBD) was used to form bacterial biofilms of selected veterinary gram-negative and gram-positive pathogenic bacteria from cattle, sheep, pigs, chicken, and turkeys. The minimum inhibitory concentration (MIC) and minimum biofilm eradication concentration (MBEC) of ampicillin, ceftiofur, cloxacillin, oxytetracycline, penicillin G, streptomycin, tetracycline, enrofloxacin, erythromycin, gentamicin, tilmicosin, and trimethoprim-sulfadoxine for gram-positive and -negative bacteria were determined. Bacterial biofilms were readily formed on the CBD under selected conditions. The biofilms consisted of microcolonies encased in extracellular polysaccharide material. Biofilms composed of Arcanobacterium (Actinomyces) pyogenes, Staphylococcus aureus, Staphylococcus hyicus, Streptococcus agalactiae, Corynebacterium renale, or Corynebacterium pseudotuberculosis were not killed by the antibiotics tested but as planktonic bacteria they were sensitive at low concentrations. Biofilm and planktonic Streptococcus dysgalactiae and Streptococcus suis were sensitive to penicillin, ceftiofur, cloxacillin, ampicillin, and oxytetracycline. Planktonic Escherichia coli were sensitive to enrofloxacin, gentamicin, oxytetracycline and trimethoprim/ sulfadoxine. Enrofloxacin and gentamicin were the most effective antibiotics against E. coli growing as a biofilm. Salmonella spp. and Pseudomonas aeruginosa isolates growing as planktonic populations were sensitive to enrofloxacin, gentamicin, ampicillin, oxytetracycline, and trimethoprim/sulfadoxine, but as a biofilm, these bacteria were only sensitive to enrofloxacin. Planktonic and biofilm Pasteurella multocida and Mannheimia haemolytica had similar antibiotic sensitivity profiles and were sensitive to most of the antibiotics tested. The CBD provides a valuable new technology that can be used to select antibiotics that are able to kill bacteria growing as biofilms.     

Effect of hay type on cecal and fecal microbiome and fermentation parameters in horses

The effect of hay type on the microbiome of the equine gastrointestinal tract is relatively unexplored. Our objective was to characterize the cecal and fecal microbiome of mature horses consuming alfalfa or Smooth Bromegrass (brome) hay. Six cecally cannulated horses were used in a split-plot design run as a crossover in two periods. The whole plot treatment was ad libitum access to brome or alfalfa hay fed over two 21-d acclimation periods with subplots of sampling location (cecum and rectum) and sampling hour. Each acclimation period was followed by a 24-h collection period where cecal and fecal samples were collected every 3 h for analysis of pH and volatile fatty acids (VFA). Fecal and cecal samples were pooled and sent to a commercial lab (MR DNA, Shallowater, TX) for the amplification of the V4 region of the 16S rRNA gene and sequenced using Illumina HiSeq. The main effects of hay on VFA, pH, and taxonomic abundances were analyzed using the MIXED procedure of SAS 9.4 with fixed effects of hay, hour, location, period, and all possible interactions and random effect of horse. Alpha and beta diversities were analyzed using the R Dame package. Horses fed alfalfa had greater fecal than cecal pH (P ≤ 0.05), whereas horses fed brome had greater cecal than fecal pH (P ≤ 0.05). Regardless of hay type, total VFA concentrations were greater (P ≤ 0.05) in the cecum than in feces, and alfalfa resulted in greater (P ≤ 0.05) VFA concentrations than brome in both sampling locations. Alpha diversity was greater (P ≤ 0.05) in fecal compared with cecal samples. Microbial community structure within each sampling location and hay type differed from one another (P ≤ 0.05). Bacteroidetes were greater (P ≤ 0.05) in the cecum compared with the rectum, regardless of hay type. Firmicutes and Firmicutes:Bacteroidetes were greater (P ≤ 0.05) in the feces compared with cecal samples of alfalfa-fed horses. In all, fermentation parameters and bacterial abundances were impacted by hay type and sampling location in the hindgut.     

The River Wadu role play — ten years experience

This paper describes a role playing planning exercise that has been used for training agriculturists, engineers and agricultural economists for more than ten years. It sets out the objectives and key features of the exercise and the experience that has been gained in its use. The exercise has been found to successfully test and integrate subject matter expertise acquired from formal teaching. It also highlights the multiple and often conflicting objectives of irrigation planning, and the need for full evaluation of alternatives and sound technical judgements under conditions of inadequate data and time pressure. The exercise is also successful in developing professional personal skills such as group working, interviewing and presentation, and is recommended as an effective training aid.