Further studies of the clinical pathology of sweating sickness in cattle

Experimentally-induced cases of sweating sickness in calves were used in an effort to correlate the blood chemistry with some of the known pathological changes. Results showed that the "sweating" associated with necrotic dermatitis did not alter blood electrolyte levels. Laboratory evidence of a disseminated intravascular coagulopathy was found which correlated with the microthrombi described in cases of sweating sickness. A high blood cortisol level was found in one of the animals that died from the disease and could possibly be used as a prognostic indicator in clinical cases. Recommendations are made with regard to the supportive treatment based on the clinical pathological findings.     

Dark lines formed between colonies of isolates of phoma exigua var. foveata on a semi-selective medium

Samenvatting In het Instituut voor Plantenziektenkundig Onderzoek (IPO) te Wageningen wordt gangreen bij aardappel, veroorzaakt door de schimmelPhoma exigua var.foveata, onderscheiden van ander droogrot door aangetast weefsel uit te leggen op een semiselectief medium. Op dit medium wordt de vorming van kristallen van voor de schimmel kenmerkende anthrachinonen bevorderd. De gemakkelijk waar te nemen geelgroene kristallen in het medium wijzen op de aanwezigheid van de betrokken schimmel. Bij een van deze toetsen vormden zich tussen de zich ontwikkelende kolonies van de schimmel donkere lijnen. Deze lijnen verschilden van reeds eerder beschreven violette lijnen, die zich vormen tussen kolonies van de twee variëteitenexigua enfoveata vanP. exigua. Onderzoek aan 27 isolaten vanP. exigua var.foveata toonde aan dat er met betrekking tot de vorming van donkere lijnen 11 verschillende typenP. exigua var.foveata onderscheiden konden worden. Isolaten van deze typen vormden bij gepaarde groei op het selectieve medium donkere lijnen met andere typen, maar niet met isolaten van het zelfde type. Er bleek geen verband met het groeitype van de cultures noch met de vorming van het antibioticum E te bestaan.     

Identification of blackeye cowpea mosaic virus from germplasm of yard-long bean and from soybean,and the relationships between blackeye cowpea mosaic virus and cowpea aphid-borne mosaic virus

Two potyvirus isolates, one from germplasm of yard-long bean (Vigna unguiculata ssp.sesquipedalis) introduced into the Netherlands, and another one from soybean plants (Glycine max) in Indonesia, were compared with two virus isolates of blackeye cowpea mosaic virus (BICMV) from the USA and a Moroccan isolate of cowpea aphid-borne mosaic virus (CAMV). It is proposed that all five isolates be now considered BICMV on the basis of host ranges, symptoms and serology. From our results, and a reassessment of the literature it is suggested to drop the name CAMV in favour of BICMV.Samenvatting Twee potyvirussen, de een in Nederland ingevoerd met genenmateriaal vanVigna unguiculata ssp.sesquipedalis en de ander uit planten van sojaboon (Glycine max) in Indonesië, werden vergeleken met twee isolaten van blackeye cowpea mosiac virus (BICMV) en een Marokkaans isolaat van cowpea aphid-borne mosaic virus (CAMV). Op grond van waardplantenreeksen, symptomen en serologie stellen de auteurs voor om alle vijf isolaten te beschouwen als BICMV. Gebaseerd op de verkregen resultaten en een kritische beschouwing van de literatuur wordt de aanbeveling gedaan om de naam CAMV te laten vallen ten gunste van BICMV.     

Waldschutz gegen Borkenkäfer: Der Beitrag von Duftstoffmeteorologie und Populationsdynamik

Zusammenfassung Mit theoretischen Modellen kann die Effektivität verschiedener Ansätze (z. B. Fallenzahl und-abstand, Ködermenge und-abgaberate) für den Einsatz von synthetischen Pheromonen in Pest-Management-Systemen verglichen werden. Das GAUSS-sche Modell, das von einer Normalverteilung der Konzentrationsabnahme um eine Lockstoffquelle ausgeht, wurde benutzt, um fürT. lineatum die lockwirksame Reichweite und die Konkurrenzsituation von Naturköder und Falle abzuschätzen. Bei 100 000 /ha und 2 Wochen Flugdauer ergeben sich für (+)-Lineatin (Reaktionsschwelle 0,1 ng/m³, Produktion 6,43 ng//d, Produktionsdauer 3 d/) mittlere Tagesraten von 128,6 g/ha bzw. eine Gesamtproduktion von 1,929 mg/ha. Die lockwirksame Reichweite x_max beträgt je nach Wetterlag für 1T. lineatum- 20–40 cm, für Fallen mit 1 CONREL-Faser (Abgaberate 10 g/d [+]-Lineatin) 13–16m. Für eine 10fach höhere lockwirksame Reichweite sind nach dem Modell etwa 100fach, in der Praxis nach verschiedenen Autoren sogar 200fach stärkere Köder erforderlich.In Freilandversuchen über die Relation von Fangleistung und Beifängen unterschiedlicher Fangsysteme waren die Coleoptera (bes. Rhizophagidae und Staphylinidae) am häufigsten. In Trichterfallen lagen die Beifänge mit 9,2% deutlich höher als in Schlitzfallen (1,2%). Das Giftpolter hatte demgegenüber das größte Beifangspektrum; hier traten auch Ordnungen auf, die von anderen Fangsystemen nicht betroffen waren.Massenfang kan prinzipiell in Holzhöfen und Waldbeständen erfolgreich durchgeführt werden. Allerdings ist das Problem der Beifänge noch ungelöst und die Relations von potentieller Vermehrung der Borkenkäfer und maximal möglicher Populationsreduzierung durch Fallenfang unbekannt. Zudem kann eine nach Massenfang geringere Populationsdichte im Folgciahr durch zunehmende Reproduktionsraten oder durch ersatzweise Einnischung (competive displacement) anderer Borkenkäferarten ausgeglichen und damit der Forstschutzeffekt zunichte gemacht werden.

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Bark beetle control: contribution of pheromone meteorology and population dynamics

The use of semiochemicals in pest management systems of bark beetles is viewed in relation to optimization of resources investment, comparing beetle numbers in univoltine, requisitegoverned woodboringTrypodendron lineatum (Oliv.) with multigeneration bark inhabitingIps typographus (L.). The efficiency of different numbers of and distance between traps and pheromone load of dispensers was analysed using steady state models and comparing results with published and own field data. Competition between traps and beetle-infested logs, attractive distance and overlap of pheromone plume was compared forT. lineatum using models which assume a GAUSS distribution of concentration decrease around a pheromone source. For (+)-lineatin (reaction threshold 0.1 ng/m³, production 6.43 ng//d, duration of production 3 d/), 100,000 /ha and a flight period of 2 weeks, daily mean production is 128.6 g/ha. Attractive distance x_max is 20–40 cm for 1T. lineatum- and 13–16 m for a trap with 1 CONREL-dispenser (mean release rate 10 g/d (+)-lineatin). A 10-fold increase of attractive distance x_max needs a 100-fold increase of pheromone release rate according to the model, and 200-fold according to field experiments.In field experiments, Coleoptera (esp. Staphylinidae and Rhizophagidae) were the most abundant non-target trap catches. Insecticide-treated trap logs had the widest range of non-target insects including orders that were not affected by the non-insecticide trapping systems. Mass trapping can be successful in logging areas and/or forests. However, the exclusion of non-target insects still is an unsolved problem and we still have only limited knowledge on potential population increase of beetles and maximum reduction that can be achieved by trapping. Also, population levels reduced by mass trapping can be compensated by increasing reproductive effort of the succeeding generation and/or competitive displacement by secondary bark beetle species.

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Mit 5 Abbildungen und 2 Tabellen

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Mit Unterstützung der Deutschen Forschungsgemeinschaft.

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Nach einem Vortag bei der Fortbildungstagung des Hessischen Forstvereins in Solms/Lahn am 23. Mai 1991.

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Herrn Prof. Dr. Dr.G. Wellenstein zum 85. Geburtstag.     

Influence of stocking density and layer age on production traits and egg quality in Japanese quail

1. Japanese quail hens were housed from 6 to 26 weeks of age in cages providing areas of 150, 180, 210 and 240 cm²/bird.

2. Body weight gain, age at 50% egg production, mortality, hen‐day egg production and food conversion values showed significant improvement with proportionate increase in cage space per layer.

3. Egg weight gradually increased with age but shell thickness was influenced neither by age of the hen nor by stocking density.

4. Yolk index and colour were superior in the lowest stocking density (more cage space) group; other egg quality traits and egg weight were not influenced by stocking density.

5. The albumen index, internal quality unit, yolk index and yolk colour values increased with age.     

Estimation of the relative bioavailability of copper sources in chicks fed on conventional dietary amounts

1. Tissue accumulation of Cu from dietary additions of 0, 5, 10, or 20 mg/kg Cu as reagent grade Cu acetate and feed grade Cu carbonate was determined in day‐old chicks fed on conventional maize‐soyabean meal starter diets (5.41 mg/kg Cu as‐fed basis) for 3 weeks.

2. Average daily food intake, daily weight gain and food conversion were similar among treatments.

3. There were linear increases in plasma and liver Cu concentrations (P< 0.01) as dietary Cu increased.

4. Bioavailability of Cu as carbonate was 0.66 that of Cu in the acetate based on the multiple regression slope ratio of liver Cu concentration on added dietary Cu. Although responses for the two Cu sources did not differ significantly, the relative bioavailability of the Cu carbonate was similar (0.66 vs 0.68) to that obtained in an earlier study (Ledoux et al., 1991) with greater dietary Cu contents (150, 300 and 450 mg/kg) in which the slopes of the equations representing the two sources differed (P<0.05).     

Book reviews

The Avian Egg: Chemistry & Biology, by R. W. Burley and D. V. Vadehra, 1989. v+472 pp. illustrated. New York. John Wiley & Sons. £66.70. ISBN 0–471–849952.

A Colour Atlas of Avian Anatomy, by J. McLelland. 1990. 127 pp. illustrated. London, Wolfe Publishing Ltd. £30. ISBN 0–7234–1575–7.

The Tropical Agriculturalist—Poultry, by A. J. Smith, 1990. vi + 218 pp. CTA/Macmillan, London. ISBN 0–333–52306–7.     

Correlated responses from selection for income minus food cost in pullets on traits in older hens

1. After 5 generations of selection on income minus food cost between 21 and 40 weeks of age (SECR), a correlated genetic improvement of 14.5% and 16.3% of the base population mean could be observed for income minus food cost between 41 and 60 weeks (IF60) in two lines of laying hens. The total responses up to 60 weeks amounted to 17.2% and 17.3% of the base population mean. A heritability of 0.30 for IF60 and a genetic correlation of 0.61 between SECR and IF60 were estimated.

2. The correlated relative genetic responses for 5 traits of the period between 41 and 60 weeks of age for the two lines were: 4.3% and 5.2% in egg number, 5.8% and 7.4% in egg weight, 8.4% and 10.8% in egg mass, ‐2.7% and ‐0.6% in body weight at 60 weeks, and ‐5.2% and ‐6.3% in food efficiency.

3. The estimated heritabilities of these 5 traits from the whole data set were 0.36, 0.75, 0.34, 0.71 and 0.17. The estimated genetic correlations between SECR and the same 5 traits were 0.30, 0.46, 0.61, ‐0.22 and ‐0.49.

4. A high genetic correlation of income minus food cost with egg weight and a low one with egg number were found in pullets, but the relationships were reversed in older hens.