Response of egg weight to the inclusion of various fats in layer diets

1. Brown egg layers were fed diets differing in oil content, oil source and linoleic acid concentration and the effect on performance from 22 to 69 weeks of age was studied.

2. The birds responded with an increasing mean egg weight up to a linoleic acid intake of 2.75 g/bird d.

3. Increasing the intake of readily absorbable oil without increasing linoleic acid concentration did not increase mean egg weight.     

The ability of biochemical and haematological tests to predict recovery in periparturient recumbent cows

Blood samples from 433 periparturient recumbent cows submitted by veterinary practitioners to Ruakura Animal Health Laboratory during 1983 and 1984 were analysed and results related to whether cows recovered, died or were euthanased. Generally cows were sampled only once and the time varied from 15 minutes to 20 days after becoming recumbent. During 1983 serum calcium, magnesium, phosphorus, creatine phosphokinase (CK), aspartate amino transferase (AST), glutamate dehydrogenase (GDH), gamma glutamyl transferase (GGT) were analysed. In 1984 serum urea, creatinine, fibrinogen and haematological examination (haemoglobin, haematocrit, total and differential white cell counts) were added to the panel. Overall 39% of cows recovered, 30% died and 32% were destroyed. Precalving cows had 111% more deaths and 7% less survivors than postcalving recumbent cows (P<0.1). There was little difference (3%) in euthanasia prevalence. Tests that were most useful in predicting a lack of recovery were serum urea and muscle enzymes. Using these tests and duration of recumbency when sampled a model was produced to predict the probability of recovery from 254 cases.     

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.     

The nutritional value of low lathyrogenic Lathyrus (Lathyrus sativus) for growing chicks

1. The feeding value of new low β‐N‐oxalyl‐amino‐L‐alanine (BOAA) lines of Lathyrus sativus (lathyrus) and the benefits of dehulling the seed or of pre‐adapting chicks to lathyrus‐based diets were examined in several experiments.

2. Chicks fed on diets containing 400 g/kg of the low (1.3 g BOAA/kg seed) and medium (2.2 g BOAA/kg seed) BOAA lines did not differ (P>0.05) in weight gain (WG) or in apparent fat and protein digestibilities compared to birds fed on a wheat‐based diet.

3. Consumption of 600 g low BOAA lathyrus/kg diet caused a slight, but significant (P< 0.05), decrease in WG. Food efficiency decreased as the amount of dietary lathyrus was increased, suggesting that lathyrus may contain an antinutritive factor(s) other than BOAA.

4. Removal of the hull (70 g hull/kg seed) from the seed did not affect chick performance (P> 0.05).

5. Pre‐adapting chicks for 7 d to diets containing up to 600 g medium line lathyrus/kg diet did not reduce the detrimental effects of the lathyrus.

6. Although dehulling and pre‐adaptation of chicks to lathyrus were not beneficial, the low and medium lines of lathyrus tested show potential for use in chick diets up to at least 400 g lathyrus/kg diet.     

Hematologic and clinico-chemical research findings in calves and young cattle with ileus

The impairment of fluid, electrolyte and acid-base status which is observed in calves and juvenile cattle as a result of ileus and subileus is not only dependent on form and site of the obstruction, but is also influenced considerably by the duration of the condition and any coexisting disease. This publication reviews the most important blood, urine and ruminal fluid parameters in such patients. The diagnostic significance of the laboratory values under discussion is not so great with obstructions to the caudal part of the digestive tract. However, markedly raised ruminal fluid chloride levels, combined with hypochloraemia and a metabolic acidosis, are indicative of an "abomasoruminal reflux syndrome" resulting from an obstruction in the region of the abomasum or cranial small intestine.