The laboratory culture of Dichelobacter nodosus in a footrot eradication program

SUMMARY As part of a program to eradicate virulent footrot from Western Australia, 2745 isolates of Dichelobacter nodosus were isolated from 5263 specimens from 1883 submissions. The virulence of each isolate was assessed using protease thermostability and isoenzyme zymogram. We describe changes to the materials and methods required to handle these specimens and to reduce the interval between submission and report to 8 days.     

Effects of delmadinone acetate on pituitary-adrenal function, glucose tolerance and growth hormone in male dogs

Objective To characterise the effects of delmadinone acetate on the pituitary-adrenal axis, glucose tolerance and growth hormone concentration in normal male dogs and dogs with benign prostatic hyperplasia.
Design A prospective study involving nine normal male dogs and seven with prostatic hyperplasia.
Procedure Delmadinone acetate was administered to six normal male dogs and seven dogs with benign prostatic hyperplasia at recommended dose rates (1.5 mg/kg subcuta-neously at 0, 1 and 4 weeks). Three normal controls received saline at the same intervals. Blood concentrations of ACTH, cortisol, glucose, insulin and growth hormone were measured over 50 days. Intravenous glucose tolerance and ACTH response tests were performed before and after treatment in the nine normal animals.
Results A substantial suppression of basal and 2 h post-ACTH plasma cortisol secretion was demonstrated after one dose in all dogs given delmadinone acetate. Individual responses after the second and third administration varied between recovery in adrenal responsiveness to continued suppression. Plasma ACTH concentration was also diminished after one treatment. No effects were evident on glucose tolerance or serum growth hormone concentrations.
Conclusion Delmadinone acetate causes adrenal suppression from inhibition of release of ACTH from the pituitary gland. Treated dogs may be at risk of developing signs of glucocorticoid insufficiency if subjected to stressful events during or after therapy. Neither glucose intolerance nor hyper-somatotropism seems likely in male dogs given delmadinone acetate at the recommended dose rate, but the potential for excessive growth hormone secretion in treated bitches remains undetermined.     

Effects of a topical anaesthetic formulation and systemic carprofen, given singly or in combination, on the cortisol and behavioural responses of Merino lambs to castration

Objective   To determine the effectiveness of a topical anaesthetic formulation (Tri-Solfen) with or without the administration of a non-steroidal anti-inflammatory drug (carprofen) on the pain and distress response associated with ring or surgical castration of ram lambs.
Procedures   Merino ram lambs (n = 78) were allocated to 10 treatment groups: 4 groups of knife-castrated lambs and 4 groups of ring-castrated lambs received carprofen (4 mg/kg SC) and Tri-Solfen; 2 control groups (sham) received carprofen at 0 or 4 mg/kg SC. Measurements included plasma cortisol and haptoglobin concentrations, haematology, and behaviour, including posture.
Results   Knife-castrated lambs had higher peak cortisol and integrated cortisol responses for the first 6 h after treatment and greater concentration s of circulating acute phase proteins than ring-castrated lambs, both of which were significantly different from the sham controls. Tri-Solfen applied to the knife castration wound significantly reduced both the peak plasma cortisol concentration and the integrated cortisol response for the first 6 h and improved lying behaviour in the first 12 h. Carprofen reduced the cortisol response to knife castration at 30 min, but elevated the cortisol responses at 24 and 48 h. Carprofen nearly halved the number of acute pain behaviours associated with ring castration. There were no significant additive or synergistic effects from combining the analgesic treatments. Tri-Solfen applied to the tail wound provided no detectible benefits during ring castration + tail docking.
Conclusions   The physiological and behavioural responses suggest that ring castration has less impact on the lamb than knife castration. The specific analgesic treatments can provide modest amelioration of the pain and discomfort associated with castration. Alternative doses or application methods may enhance their efficacy.     

Treatment of rupture of suspensory ligament and superficial flexor tendon in a bull

Rupture of the suspensory ligament at the insertions on the proximal sesamoid bones, and of the superficial flexor tendon of the left fore limb, occurred in an adult Angus bull as a result of fighting. There was severe hyperextension of the metacarpophalangeal (MCP) joint with the dewclaws almost touching the ground. Radiographs revealed severe hyper-extension of the MCP joint with the sesamoid bones aligned directly distal to the metacarpus. Initially, a full length fiberglass cast was applied with the limb partially flexed within the cast and the heels elevated. The cast was replaced twice. The cast was removed after 136 days and the bull was bearing full weight on the limb. Prolonged immobilisation of the limb produced new bone in the area (a normal response in cattle) to cause ankylosis of the traumatized MCP joint and partial ankylosis of the carpus. The bull was being used for pasture breeding one year after the injury.     

Enzymes as silage additives 2. The effect of grass dry matter content on silage quality and performance in sheep

Eight grass silages were made from two contrasting varieties of perennial ryegrass, four silages each from a late-cut early-maturing (high dry matter, HDM) variety and from an early-cut, late-maturing (low dry matter, LDM) variety. The grass was ensiled without additive (untreated), or with formic acid, or with one of two enzyme mixtures of hemicellulases and cellulases (enzyme 1 and enzyme 2) for a period of 130 d.
Formic acid-treated silage had lower levels of lactic acid at both levels of dry matter than the other silages. Enzyme treatment of grass prior to ensilage resulted in reduced levels of cellulose, acid-detergent fibre and neutral-detergent fibre in LDM silages and lower acid-detergent fibre and neutral-detergent fibre in the HDM silages compared with the corresponding untreated and formic acid-treated silages. Voluntary intakes (g DM d⁻¹) of untreated and enzyme-treated silages were significantly ( P <0·01) lower at both digestibilities compared with formic acid-treated silages (LDM: untreated, 982; formic, 1069; enzyme 1, 868; enzyme 2, 937; HDM: untreated, 931; formic, 1027; enzyme 1, 943; enzyme 2, 914). The organic matter, carbohydrate and nitrogen digestibility coefficients of LDM silages were significantly ( P <0·001) higher than those of HDM silages. There were no significant differences in any component digestibility related to silage additive.
Comparison of digestibility coefficients for constituents of the LDM silages fed to sheep or steers showed no differences between species.     

Factors affecting development of Septoria tritici in winter wheat and its effect on yield

Severe infection with Septoria tritici occurred in four of five experiments designed to create a series of different disease epidemics. These experiments successfully identified periods suitable for infection. They also indicated the effect of sprays, timed before and after these periods, on disease development and yield.
Analysis of disease progress and weather records suggested that critical conditions for initial development of S. tritici occurred during early May at four sites. Heavy rain giving at least 10 mm on 1 day or a total of 10 mm or more on 2 or 3 successive days occurred at all four sites prior to the appearance of symptoms on a particular leaf layer, though less heavy rain may suffice to splash inoculum onto upper leaves in shorter, immature canopies where stem elongation is incomplete. At the fifth site, infection occurred later in May and disease failed to develop to a significant degree. At all sites, the length of the incubation period on any of the top three leaves was found to be between 396 and 496 degree days.
Control of winter epidemics of S. tritici had little effect on yield, whereas spray sequences commencing later than growth stage (GS) 31 but immediately prior to the critical periods provided the best disease control and yield benefit. Regression models incorporating, as independent variables, area under the S. tritici disease progress curve for any of the top three leaves from their emergence (GS 32-37) satisfactorily explained yield loss at the four sites where disease was severe. Consideration of leaf 2 or leaf 3 alone accounted for more than 82% of the variance at each site and a yield loss from infection of leaf 2 related to thermal time is suggested as 0.00265% per C per day from the appearance of symptoms.     

Control of Glomerella cingulata f.sp. camelliae with fungicides

A critical test of fungicidal activity against the wound pathogen Glomerella cingulata f.sp. camelliae on camellias involved the application of a conidial suspension to scratches on detached leaves, treated with fungicide 24 h previously. In this test, prochloraz at 250–500 μg/ml a.i. in both EC and manganese WP formulations was highly effective, inhibiting leaf rotting by 90–100% compared with 55% or less in some tests with benomyl, chlorothalonil and captafol at 500–1000 μg/ml and captan at 1200 μg/ml. Prochloraz gave similar protection to leaves when applied to whole plants. Protection was less, especially on older leaves, when wounding and inoculating were delayed by 7 or more days after treatment. Prochloraz did not prevent all infection through comparatively large wounds, e.g. leaf scars, made on stems 24 h after treatment.
Poor control of the disease in a nursery was not due to resistance of the pathogen to benomyl; in vitro tests failed to detect full resistance at this time. Under nursery conditions a statutory policy of destroying infected plants and spraying the remainder with prochloraz or prochloraz manganese (both at 500 μg/ml), alternating with benomyl (500 μg/ml) on a weekly basis apparently prevented spread of the disease to healthy plants.     

Powdery mildews on borage (Borago officinalis) and evening primrose (Oenothera biennis)

The powdery mildews Erysiphe cynoglossi and E. howeana, causing disease on borage (Borago officinalis) and evening primrose (Oenothera biennis), respectively, are reported for the first time in Britain.     

Clasterosporium flexum (T. Matsush.) comb. nov. on dying cuttings of Chamaecyparis lawsoniana in UK

A dematiaceous fungus forming a network of hyphopodiate hyphae over foliage of Chamaecyparis lawsoniana cuttings dying under mist propagation has been identified as Clasterosporium flexum (T. Matsush.) comb. nov. The concept of the genus Clasterosporium in relation to the genera Sporidesmium and Ceratophorum is discussed.