Simulation-aided development of the Hawaii swine research programme

A computer model is presented to estimate the quantitative impact of future research/extension activities in various aspects of swine production on the profit of an average swine producer in Hawaii. The model was designed and used to generate information for making decisions regarding funding of future research/extension projects in the swine production area. The computer model has two components. The first simulates the biological production behaviour of a typical pig enterprise of Hawaii. The General Purpose Simulation System (GPSS) language was used to model the stochastic nature of the production. For a given set of biological parameters, this component provides annual production levels, feed consumption and statistics for selecting the capacity of various building facilities. The second component computes annual revenues, costs and rate of return to capital investment over the analysis period by using discounted cash flow method. In addition to other cost and price data, it uses the output of the first component as input.     

The enterotoxin and other plasmids of enteropathogenicEscherichia coli

Several characters ofEscherichia coli enteropathogenic for farm animals and man are determined by transmissible plasmids. These include the production of K88 and K99 antigens, enterotoxin and haemolysin. The construction of bacteria of a desired plasmid composition provides an elegant method of obtaining information on these characters. Such studies have revealed that the K88 antigen is importantly involved in the ability of enteropathogenicE. coli to proliferate in the small intestine of piglets and that the K99 antigen performs a similar function inE. coli enteropathogenic for calves and lambs. Enterotoxin is mainly responsible for the diarrhoea that then ensues.

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Kurzfassung Mehrere pathogene Eigenschaften der E. coli für Mensch und Haustier werden durch übertragbare Plasmiden bestimmt. Dazu gehört auch die Produktion von K88 und K99 Antigenen, von Enterotoxinen und Hämolysin. Die Entwicklung von Bakterien mit der gewünschten Plasmazusammensetzung stellt eine gute Methode dar, Information über diese Eigenschaften zu gewinnen. Untersuchungen dieser Art haben gezeigt, dass K88 Antigene die Vermehrung von E. coli im Dünndarm von jungen Schweinen, fördert, und dass K99 Antigene eine ähnliche Wirkung auf die enteropathogenen E. coli bei Kälbern und Lämmern haben. Enterotoxin ist die Hauptursache für die dabei auftretende Diarrhoea.

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Resume Plusieurs caracteres d'Escherichia coli enteropathogenes pour les animaux de ferme et l'homme sont determines par des plasmides transmissibles. Ceux-ci incluent la production d'antigenes K88 et K99, d'enterotoxine et d'hemolysine. Un modile de bacterie ayant la composition plasmidique desiree fournit une methode elegante pour l'obtention d'une information sur ces caracteres. De telles etudes ont montre que l'antigene K88 intervient de facon marquee dans l'aptitude d'E. coli enteropathogene a proliferer dans l'intestin grole de porcelets et que l'antigene K99 a une fonction similaire pourE. coli enteropathogene des veaux et des agneaux. L'enterotoxine a une respourabilite majeure dans la diarrhee.

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Riassunto Alcuni caratteri dell'E. coli patogeno per l'uomo e per gli animali domestici sono determinati da plasmidi transmissibili. Questi comprendono la produzione di antigeni K88 e K99, di enterotossina e di emolisina. Un modello di batteri della composizione plasmidica desiderata fornisce un metodo ideale per l'ottenimento di informazioni su questi caratteri. Tali studi hanno dimostrato che l'antigene K88 svolge un ruolo importante nella proliferazione dell'E. coli enteropatogeno nell'intestino tenue dei porcellini e che l'antigene K99 svolge una funzione simile per l'E. coli enteropatogeno dei vitelli e degli agnelli. L'enterotossina e il maggior responsbile della diarrea che ne consegue.

     

Enzyme-linked immunosorbent assay for detecting antibodies to Brucella abortus in bovine milk and serum

An enzyme-linked immunosorbent assay (ELISA) method was evaluated for the detection of antibodies to Brucella abortus in cows milk. Milk samples from seropositive or -negative cows were sed to determine the distribution of absorbance values to classify milk as ELISA positive or ELISA negative. Brucella abortus was isolated from milk samples from 10 (45%) of the 22 cows whose milk and serum were ELISA positive. The ELISA was evaluated and determined to be an appropriate method for detecting antibodies to B abortus in bovine milk.     

Determination of residues of isofenphos and its phosphoramidate analogue

A method is described for the gas chromatographic determination of residues of isofenphos (BAY 92114, O-ethyl O-2-isopropoxycarbonylphenyl isopropylphosphor-amidothioate) and its phosphoramidate which is a potential metabolite. When potato, cabbage, rapeseed and a sandy loam soil were fortified with 0.01, 0.1 and 1.0 mg/kg and analysed by the method described, the recoveries ranged from 76 to 98%. The limits of detection of the method were 0.5 and 1.0 ng for isofenphos and isofenphos oxygen analogue respectively. Degradation under field conditions of isofenphos to its oxygen analogue was demonstrated in a sample of field-treated potatoes.     

Reduced tear production in three canine endocrinopathies

OBJECTIVES: Previous reports have suggested that hypothyroid and diabetic patients can be predisposed to keratoconjunctivitis sicca. This study aimed to measure tear production in dogs with diabetes, hypothyroidism and hyperadrenocorticism using the Schirmer tear test and to compare these results with Schirmer tear test values for a group of normal dogs. METHODS: Schirmer tear tests were performed on 16 dogs with hyperadrenocorticism, 18 with diabetes and 12 with hypothyroidism together with 100 control dogs. Corneal sensitivity was also measured in 12 of the 18 diabetic dogs with a Cochet Bonnet aesthesiometer and compared with age- and breed-matched normal dogs. RESULTS: Schirmer tear test values in dogs with hypothyroidism, hyperadrenocorticism and diabetes were 12.3+/-3.2, 14.0+/-4.0 and 12.3+/-5.3 mm/minutes, respectively. Schirmer tear test values were significantly lower than that for the control group (19.6+/-4.2 mm/minutes) in all dogs with an endocrinopathy. Only in two hypothyroid dogs and three diabetics, this was manifested as profound keratoconjunctivitis sicca with Schirmer tear test value lower than 5 mm/minutes. Diabetic dogs had significantly reduced corneal sensitivity compared with a matched set of control dogs. CLINICAL SIGNIFICANCE: This study shows a significant reduction in tear production in animals with diabetes mellitus, hypothyroidism and hyperadrenocorticism. Further research is needed to elucidate the mechanisms by which this reduction in tear production occurs. Assessment of tear production should be undertaken in animals diagnosed with these endocrinopathies, as these animals may progress to clinical keratoconjunctivitis sicca.