Mycotoxicoses of animals

Mycotoxicoses are intoxications caused by ingestion of foodstuffs contaminated with mycotoxins, i.e. toxic secondary metabolites of microscopic filamentous fungi (moulds). By field observations and by experimental testing, toxins or toxic strains of more than 100 species of fungi have been encountered. However, causal associations have so far only been established for a small number of mycotoxicoses in farm animals, and the more important mycotoxicoses are aflatoxicosis, facial eczema, mycotoxic nephropathy, and estrogenic syndrome. A full assessment of the impact of mycotoxins on the health of farm animals can hardly be made at present, because the amount of surveillance data from mycotoxicoses is very limited, due mainly to inadequate diagnostic criteria. A new set of criteria for the diagnosis of mycotoxicosis is proposed, which has been successfully applied in the causative study of mycotoxic porcine nephropathy.     

The gastric mucus of domestic animals

The gastric mucus of different domestic mammals shows a certain pattern of reactions which is typical for the species but not for the respective gland. There is no "mucoid" as an uniform specific mucus substance and a greater plurality in the composition of the secretions as it is reflected by the classification in acid and neutral mucins. A classification of the glands as to the secretion is problematical and further consideration is necessary.     

Manipulation of fertility in domestic animals

For many years artificial insemination has been widely used for the manipulation of fertility in farm animals and more recently methods for the synchronization of oestrous cycles, superovulation and embryo transplantation have been increasingly applied. These techniques now provide new opportunities for the manipulation of gametes and embryos which might further enhance reproductive potential through the production of embryos in vitro, their preservation by deep freezing, cloning from embryonic cells or genetic manipulation to increase fecundity.     

Climatic stress indices for domestic animals

Past attempts to devise an index of climatic stress are briefly reviewed, and a new Relative Strain Index (RSI) is proposed. RSI is the ratio between the evaporative cooling required to compensate for the heat stress, and the maximum evaporative cooling that the animal can provide by physiological means. RSI takes into account the air temperature, vapor pressure, air movement,and radiant heat exchange,as well as the metabolic rate and insulation provided by the animal's coat. Thè index can be used to predict the probable tolerance of animals of types that have been sufficiently well studied. It can also be used to estimate the relative tolerances of animals having different physiological capacities or metabolic rates, but otherwise comparable; and it can be used to predict the relative effectiveness of proposed environmental controls.

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Zusammenfassung Die früheren Versuche, einen Index für den Klima-Sbress auszuarbeiten,werden kurz beschrieben und ein neuer Relativer Belastungsindex (relative strain index — RSI) wird vorgeschlagen. RSI ist das Verhältnis zwischen der Verdunstungskälte, die zur Kompensation der Hitzebelastung benötigt wird, und der maximalen Verdunstungskälte des Tieres, die physiologisch möglich ist. RSI berücksichtigt die Lufttemperatur, den Dampfdruck, die Luftbewegung und den Strahlungswärmeaustausch, fernèr die Höhe des Stoffwechsels und die Wärmeisolation durch das Fell. Der Index kann benutzt werden, um die wahrscheinliche Toleranz der Typen von Tieren vorherzusagen, die in ausreichender Weise erforscht worden sind. Er kann ebenfalls dazu verwendet werden, die relativen Toleranzen von Tieren abzuschätzen,die verschiedene physiologische Fähigkeiten oder Stoffwechselraten haben,aber im übrigen vergleichbar sind. Schliesslich kann er bei der Vorhersage der relativen Wirksamkeit der beabsichtigten Kontrollen des Umweltmilieus benutzt werden.

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Resume Les essais antérieurs d'élaboration d'un Indice de Contrainte Thermique sont brièvement décrits et un indice nouveau, appelé Indice de Charge Relative (relative strain index = RSI) est proposé. Cet indice est le quotient de la déperdition calorique par évaporation nécessaire en vue de compenser la charge thermique,sur la déperdition calorique maxima par évaporation physiologiquement réalisable par un animal. Cet indice tient compte de la température de l'air,de la pression partielle de vapeur d'eau, de la vitesse de l'air et des échanges par rayonnement thermique,ainsi que de la production de chaleur métabolique et de l'isolement calorique par le pelage. L'index peut être utilisé pour prédire la tolérance probable à la chaleur, d'espèces animales dont les modalités de thermorégulation sont déjà suffisamment bien connues. Il peut être utilisé en outre pour évaluer la tolérance relative d'animaux différant par leurs niveaux métaboliques ou par leurs capacités physiologiques; il peut enfin être utilisé pour prédire l'efficacité relative de divers moyens d'agir sur les conditions thermiques ambiantes.

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Parts of this paper were presented during the Third International Biometeorological Congress,Pau,France, 1–7 September 1963.     

Occurrence of campylobacters in small domestic and laboratory animals

Faeces samples from 156 healthy domestic pets and laboratory animals were examined for campylobacters with both a selective medium (Campylobacter Blood Free Medium; Oxoid, CM739) and selective filtration through a 0.65 μm pore size filter. Campylobacter spp. were isolated from 78 of the samples; filtration was the most effective method. Isolates were characterized by biochemical tests and DNA/DNA hybridization with whole chromosomal DNA from reference strains as probes. Campylobacter upsaliensis was the most common species isolated from cats (45 from 68 samples) whilst Camp. jejuni was more often isolated from dogs (19 from 56 samples). More attention should be paid to pets as a potential source of campylobacters capable of causing diarrhoea in human beings. Procedures other than those involving currently-used selective agents must be employed to efficiently detect all campylobacters.