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Ohne Zusammenfassung     

Field trials of an immunization procedure against hemorrhagic enteritis of turkeys

The efficacy of oral vaccination for hemorrhagic enteritis of turkeys was assessed by comparing flocks raised on the same premises, under the same management, with and without vaccination. The immunizing virus, a strain of marble spleen disease virus of pheasants, was administered via the drinking water. Vaccinated and unvaccinated turkeys differed significantly in feed conversion rates and spleen weights after challenge.     

Enhancement of bone healing using non-glycosylated rhBMP-2 released from a fibrin matrix in dogs and cats

OBJECTIVES: To test a non-glycosylated recombinant human bone morphogenetic protein-2 (ngly-rhBMP-2)/fibrin composite, which has been shown experimentally to enhance healing of bone defects in rodents, in a clinical case series of dogs and cats undergoing treatment for fracture non-unions and arthrodesis. METHODS: A ngly-rhBMP-2/fibrin composite was applied in 41 sites in 38 dogs and cats for which a cancellous bone autograft was indicated, replacing the graft. RESULTS: Bridging of the bone defect with functional bone healing was achieved in 90 per cent of the arthrodesis and fracture nonunions treated in this manner. CLINICAL SIGNIFICANCE: This prospective clinical study demonstrates the beneficial effects of ngly-rhBMP-2 in a specially designed fibrin matrix on the treatment of bone defects, and validates the use of this composite as an alternative to bone autografts in dogs and cats.     

Biological responses to porcine respiratory and reproductive syndrome virus in pigs of two genetic populations

One hundred pigs from the NE Index Line (NEI) and 100 Hampshire-Duroc cross pigs (HD) were inoculated intranasally with porcine respiratory and reproductive syndrome virus (PRRSV 97-7895 strain) at 26 d of age to determine whether genetic variation in response to PRRSV exists. An uninfected littermate to each infected pig served as a control. Pigs were from 163 dams and 83 sires. Body weight and rectal temperature were recorded, and blood samples were drawn from each pig on d 0 before inoculation and on d 4, 7, and 14 after inoculation. Pigs were sacrificed on d 14. Lung and bronchial lymph nodes were collected, placed in optimal cutting temperature compound, and frozen at -80 degrees C. The presence of PRRSV in serum and in lung tissue and bronchial lymph nodes was determined by isolation in cell culture. The presence of antibodies in serum collected on d 14 was determined by a commercial ELISA test. Lung tissue was examined microscopically and scored for incidence and severity of lesions (score of 1 to 3; 1 = no or few lesions, and 3 = severe interstitial pneumonia). Data were analyzed with a mixed model that included random sire and dam effects. The interaction of line x treatment was significant (P < 0.001) for weight change and rectal temperature. Un-infected HD pigs gained 0.67 kg more from d 0 to 14 and averaged 0.32 degrees C higher rectal temperature than uninfected NEI pigs (P < 0.001), whereas infected NEI pigs gained 0.34 kg more and had -0.54 degrees C lower temperature than infected HD pigs (P < 0.001). Viremic titer (cell culture infectious dose 50%/mL) was greater (P < 0.05) in HD than NEI at d 4 (10(4.52) vs. 10(4.22)), 7 (10(4.47) vs. 10(3.99)), and 14 (10(3.49) vs. 10(3.23)). Viral titer loads in lung (P = 0.11) and bronchial lymph nodes tended (P = 0.07) to be greater in HD than NEI pigs. Antibody signal-to-positive (S/P) ELISA ratios in infected pigs ranged from 0.18 to 3.38, and 88% had levels > or = 0.40, which is the positive threshold for this ELISA. The S/P range in uninfected pigs was 0 to 1.11, and 99% had levels < or = 0.40. Mean S/P ratio for infected pigs was 0.23 units higher in HD than in NEI (P < 0.001). The HD pigs had a greater incidence of interstitial pneumonia and 0.65 higher mean lesion scores than NEI pigs (P < 0.001). In summary, responses of pigs of the two lines to infection with PRRSV differed, indicating that underlying genetic variation existed.     

The in vitro developmental competence of oocytes from juvenile calves is related to follicular diameter

This study investigated the relationship between follicle size (FS) and developmental competence of calf oocytes. Cumulus-oocyte-complexes (COCs) from follicles>8 (L-COCs; n=19), 4-8 (M-COCs; n=54), and 2-3 mm (S-COCs; n=155) were recovered from non-stimulated 1-4 months old dairy calves post mortem and ex vivo (laparoscopy), and in parallel from slaughtered adult cows from follicles of identical size categories [>8 (n=91); 4-8 (n=138); 2-3 mm (n=193)]. Morphologically intact COCs were subjected to in vitro maturation, fertilization, and embryo culture. Cleavage rate (CR; 46 h post-insemination=p.i.), rate of morulae/blastocysts (M/Bl; day 7 p.i.), and blastocysts (Bl; day 9 p.i.) were recorded. FS had no effect on the CR in calves. However, calf L-COCs yielded the highest rates of M/Bl and Bl compared with the two other size categories (P<0.05). In contrast, calf S- and M-COCs gave similar rates of M/Bl, whereas the proportion of Bl was lowest for S-COCs (P<0.05). This was almost identical to findings in cows, except that the CR was highest for L-COCs and M/Bl yields were lowest for S-COCs (P<0.05). There were no differences between calf and cows with regard to CR for the respective FS categories. L-COCs from calves and cows yielded similar rates of M/Bl and Bl, whereas calf S- and M-COCs yielded lower rates of Bl than S- and M-COCs from cows and a lower rate of M/Bl when S-and M-COCs were analyzed as one group (P<0.05). Whereas the CR was similar in calves and cows, calf COCs yielded lower rates of M/Bl and Bl (P<0.05). In conclusion, the results show that the developmental competence of calf oocytes is higher in those derived from follicles larger than 8 mm, and thus are almost equally as competent as cow oocytes derived from follicles of identical size. This suggests that calf oocytes acquire developmental competence within the large follicle, potentially due to a process similar to prematuration of the oocyte in the adult cow. It is proposed that procedures that facilitate prematuration, such as "coasting" following a preceding superstimulation, might increase the developmental competence of calf oocytes.     

Biofilm formation is prevalent among field isolates of Actinobacillus pleuropneumoniae

A total of 77 field isolates and 15 reference strains of the porcine respiratory pathogen Actinobacillus pleuropneumoniae were tested for their ability to form biofilms in a polystyrene microtiter plate assay. More than half of all field isolates, which included strains representing serotypes 1, 5 and 7, but only two reference strains (serotypes 5B and 11) exhibited biofilm formation. Strains that formed biofilms in microtiter plates also formed thick biofilms at the air-liquid interface when cultured in glass tubes with agitation. The biofilm formation phenotype was maintained indefinitely when cultures were passaged on agar but was lost after one or two passages in broth. Our findings indicate that biofilm formation is a prevalent phenotype among A. pleuropneumoniae field isolates, and that this phenotype may have been previously overlooked because of its tendency to be lost upon subculturing in broth. Biofilm formation may have relevance to the colonization, pathogenesis and transmission of this bacterium.     

Oesophageal strictures in cats associated with doxycycline therapy

Four cases of oesophageal stricture subsequent to doxycycline administration are reported. All cases were young to middle age (median age 3 years; range 1-7 years), and either domestic shorthair or domestic longhair breed. In all cases the predominant clinical sign was regurgitation, which developed at variable times after doxycycline administration. In all cases the reason for doxycycline use was treatment or prophylaxis of suspected infections (Mycoplasma haemofelis, Chlamydophila felis or Bordetella bronchiseptica), and the duration of therapy was variable. In one case the stricture was definitively diagnosed at post mortem examination, in the three other cases, definitive diagnosis was by endoscopy. Balloon dilation was successful in the three cases that were treated. This is the largest case series, to date, of oesophageal disease in cats associated with doxycycline administration. Caution should be exercised when administering oral medication to cats, especially doxycycline, and should be accompanied either by a water or food swallow.     

Untersuchungen über Beziehungen von Schwarzfleckigkeit und Gewebemerkmalen bei Kartoffelknollen

Zusammenfassung Es wird das Auftreten von Schwarzfleckigkeit und ?usseren Besch?digungen an Kartoffelknollen nach mechanischer Belastung ermittelt und der Einfluss von Dicke und Festigkeit der Rindenschicht sowie der Lignifizierung der Gef?ssbündelzone auf die Entstehung der Schwarzfleckigkeit untersucht. Dabei zeigt sich, dass diese Merkmale im allgemeinen nicht als bestimmende Faktoren wirken, aber zur Deutung von zum Trockenmassegehalt abweichend hoher Schwarzfleckigkeitsneigung eines Genotyps beitragen k?nnen. Ein hoher Zellwandgehalt des Knollengewebes beeinflusst nicht signifikant die Schwarzfleckigkeitsneigung eines Genotyps. Zellwanddefekte dürften daher keine wesentliche Rolle bei der Entstehung der Schwarzfleckigkeit spielen.

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Summary The following tuber tissue characters were determined on a collection of 23 genotypes (harvest years 1974 to 1976, 3 different experimental sites): (1) thickness of the cortical zone; (2) crude cell wall content of the cortical and medullary tissues; (3) lignin content of the vascular ring; (4) dry matter content; and (5) resistance of the tubers to mechanical damage. The influence of these characters on blackspot was examined. Apart from certain exceptions, no significant correlations were established between blackspot and characters 1, 2, 3 and 5 (Table 1). It must be emphasised that the cell wall content of the tubers certainly influences their resistance to external injury (Weber, 1978), although not any tendency to the development of blackspot. Genotypes with a high and those with a low cell wall content can both develop slight or severe blackspot (Table 2). Therefore, the defect leading to the development of blackspot lies not with the cell walls but rather with the cell contents. There is a correlation throughout between dry matter content and blackspot of r=0,7 to 0,8 (Fig. 1). Genotypes with a negative deviation from this relationship have a relatively thin cortical layer and a relatively high degree of lignification of the vascular ring (Table 2). It is probable that these characters only influence the development of blackspot in the tubers when definite threshold values are either not reached or are exceeded. Characters 1, 4, 5 and blackspot show significant differences between experimental sites and between years (Table 4).

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Résumé Plusieurs caractères du tissu du tubercule de la pomme de terre ont été déterminés sur un assortiment de 23 génotypes (récolte 1974 à 1976 et 3 lieux): (1) épaisseur de la zone de l'épiderme; (2) teneur en parois cellulaires des tissus de l'épiderme et de la moelle; (3) teneur en lignine dans la zone des vaisseaux vasculaires; (4) teneur en matière sèche; (5) résistance du tubercule aux blessures. L'influence de ces caractères sur les taches plombées a été étudiée. A part quelques exceptions, il n'a pas été obtenu de corrélation significative entre l'intensité des taches plombées et les caractères 1, 2, 3 et 5 (tableau 1). La teneur en parois cellulaires du tubercule influence la résistance aux chocs (Weber, 1978), mais pas la sensibilité aux taches plombées. Aussi bien les génotypes riches que les génotypes pauvres en parois cellulaires sont sensibles ou résistants aux taches plombées (tableau 2). Les taches plombées formées après les chocs ne paraissent pas provenir de dégats des parois cellulaires, mais de l'intérieur de la cellule. Une corrélation de r=0.7 à 0.8 a été obtenue entre la teneur en matière sèche et le taux de taches plombées (fig. 1). Les génotypes qui ne suivent pas cette relation ont une couche épidermique relativement mince ainsi qu'un taux élevé de lignine dans la zone des vaisseaux vasculaires (tableau 2). Il semblerait que ces caractères influencent la formation de taches plombèes uniquement lorsque certaines limites marginales ne sont pas atteintes. Les caractères 1, 4, 5 et les taches plombées ont présenté des différences significatives entre lieux et années (tableau 4).