Comparative studies on bone structure in dairy cows with different feeding conditions

The bone belongs to the dynamic tissues and its structure in domestic cows is still not completely understood in correlation to the impact of different food components. The aim of our work was a histomorphometrical and immunohistochemical research on bone morphology and factors influencing it in healthy dairy cows fed with self-produced grain and with rapeseed cakes. The bone of self-produced grain-fed cows demonstrated statistically significant difference in the number of osteocytes from the bone of rapeseed cakes-fed cows. The rapeseed cakes-fed cows didn't show any bone cell positive for BMP2/4, while FGFR1 increased significantly in their supportive tissues. The number of bFGF- and apoptosis-containing structures varied in cows of both groups. MMP2 expression showed statistically significant difference between both animals' groups with domination in bone of cows fed with self-produced grain. Defensin-, osteopontin- and osteocalcin-containing cells showed tendency to increase in bone of cows on rapeseed cakes diet. Conclusions. The rapeseed-fed cow's long bones demonstrate significant decrease of osteocytes per mm2 and selective increase of FGFR1, suggesting the (compensatory) growth stimulation in supportive tissue. The statistically significant selective absence of MMP2 with a slight tendency of increase in osteopontin and osteocalcin in rapeseed-fed cow's long bones indicates the persistence of seemingly still compensated qualitative changes in bone (beginning of disturbances in mineralization, metabolism etc.) proved also by a slight increase of the bone antimicrobial peptide.     

Characterization of antigens from mycoplasmas of animal origin

Alcholeplasma laidlawii, Mycoplasma gallisepticum, M mycoides subsp mycoides, M agalactiae, M bovirhinis, mycoplasmal strain ST-6, and culture medium were compared with M bovis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, enzyme-linked immunosorbent assay (ELISA), and gel electrophoresis-derived ELISA. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated there were areas of homology and areas of heterology among the species tested. Sera from rabbits hyperimmunized with the mycoplasma organisms and noninoculated culture medium demonstrated ELISA reactivity with M bovis antigens immobilized on polystyrene. Absorption of the serum from a rabbit hyperimmunized with M bovis reduced 65.9% of its reactivity with culture medium, 29.7% to 32.7% of its reactivity with the heterologous species, and 21.1% of its reactivity with the homologous species. Gel electrophoresis-derived ELISA performed on immobilized M bovis antigens separated by molecular weight, using sera from rabbits hyperimmunized with the mycoplasmal species under study and noninoculated culture medium revealed antigenic components which are shared among species or with the culture medium and several components which may be unique to M bovis.     

Investigation of the viability of M. bovis under different environmental conditions in the Kruger National Park

The survival time of Mycobacterium bovis in the natural habitat of infected free ranging wildlife was investigated. Seven different experimental sites near Skukuza in the Kruger National Park, South Africa, were selected to expose macroscopically affected lung or lymph node tissue of African buffalo (Syncerus caffer) origin and spiked faecal specimens for various lengths of time over a 1-year period. Mycobacterium bovis could be isolated for a maximum period of 6 weeks from tissue specimens and 4 weeks from faeces. The longest survival of M. bovis in both specimen types was observed in winter and under moist conditions. Surprisingly, the survival time of M. bovis in buried specimens seemed greatly reduced to a maximum of 5 days.     

Comparative study of different methods for dog semen cryopreservation and testing under clinical conditions

The extenders and freezing rates from three different freezing protocols were combined and compared to each other in order to study the post-thawing acrosome integrity and fertility of frozen dog sperm. A commercial bovine TRIS-base extender (TRILADYL) and two self-made canine semen extenders (Norwegian and Dutch) were combined with a conventional bovine and two canine freezing regimes, and acrosome integrity of frozen/thawed spermatozoa was assessed by fluorescein isothiocyanate conjugated peanut agglutinin staining (FITC-PNA). Differences between freezing/thawing protocols were reflected in the proportion of cells with acrosomal damage and not based on motility results. It was concluded that during dog semen cryopreservation extenders had less influence on the post-thawing sperm quality than did the freezing rates. The optimal extender/freezing rate combination (TRILADYL/Norwegian) was used in the clinical practice to evaluate the fertility of frozen sperm administered by intrauterine insemination using a surgical approach. The pregnancy rate was 57% (4/7), but the average litter size was low (2.8). This may have been due to the insufficient sperm numbers contained in an insemination dose and/or to the incorrect timing of artificial insemination (AI). The final conclusion is that the commercial bovine extender is useful for freezing dog semen, and the TRILADYL/Norwegian freezing protocol is recommended as the most advantageous combination for the freezing of canine semen in the clinical practice.     

The "in vitro" effect of antibiotics on mycoplasmas under conditions of the preparation of bull sperm

Bull sperm was experimentally contaminated with Mycoplasma (M.) bovis, M. bovigenitalium, and Acholeplasma laidlawii (10(5) colony-forming units/ml sperm). Antibiotics were tested for their effectiveness under conditions of preparation of sperm for artificial insemination, primarily for their capability of killing all mycoplasma by the end of sperm equilibration (cooling to +4 degrees C within 5 h). Mycoplasma decontamination was achievable only by means of nourseothricin and lincospectin, in a concentration of 0.8 mg/ml sperm diluent which did not yet impair bull sperm vitality.     

Possible application of oxidative stress parameters for the evaluation of animal welfare in sheltered dogs subjected to different environmental and health conditions

The objective of this study was to establish an additional prognostic parameter to assess animal welfare. We explored the validity of using the thiol antioxidant barrier (SHp) and determination of reactive oxygen metabolites (dROMs) as indicators of stress and welfare in sheltered dogs. The shelter is a stressful environment for a dog because of its unpredictable and uncontrollable nature. The dogs enrolled in the present study belonged to 2 types of animal shelters (shelter 1 and shelter 2) that differed for social and spatial restrictions for the dogs. Animals were tested for leishmaniosis and ehrlichiosis and divided into 4 groups on the basis of their negative (group A and B) or positive (group C and D) status and the shelter they belonged to. The Student t test showed significant differences on SHp concentrations between groups A and B (negative titers; different shelters) (P < 0.0001; t₍₁₀₎ = 11.08), groups C and D (positive titers; different shelters) (P < 0.02; t₍₇₎ = 2.998), and groups A and C (different infection status and same shelter) (P < 0.004; t₍₈₎ = 3.975). Levels of dROMs showed significant differences between groups A and C (different infection status and same shelter) (P < 0.03; t₍₈₎ = 2.552) and groups B and D (different infection status and same shelter) (P < 0.02; t₍₉₎ = 2.817). The high dROMs values recorded in all dogs during the study may be because of the stressful environment of animal shelters, in general. The low SHp concentrations that we found in dogs from shelter 1 may suggest a highly stressful condition related to the poor social environment for interaction. SHp and dROMs may provide useful information about the responsiveness of sheltered dogs subjected to different environmental (social and spatial restrictions, management practices, and diet) and health (negative or positive status for leishmaniosis and ehrlichiosis) conditions and may suggest the possibility of establishing an additional prognostic tool for the assessment of welfare and health in sheltered dogs.     

Further studies on the morphology and isolation of feline mycoplasmas

The colonial characteristics of Mycoplasma felis and M. gatae are described and illustrated. It is suggested that these characteristics may be used as a method of identification for these two feline mycoplasmas. An assessment is made of the efficacy of recovering mycoplasmas from the throats of cats using both solid and liquid media. The importance is emphasized of using liquid media when attempting to isolate mycoplasma from animals or their tissue.
Résumé. Les caractéristiques de Mycoplasme felis et M. gatae inhérentes è la colonie sont décrites et illustrées. On suggère l'utilisation de ces caractéristiques comme moyen d'identification de ces deux mycoplasmes félins. On examine dans yuelle mesure le prkélèvement des mycoplasmes de la gorge des chats au moyen d'agents tant solides que liyuides s'avère efficace d'utiliser. On souligne l'importance des agents liquides pour isoler le mycoplasme des animaux ou de leur tissu.
Zusammenfassung. Die Kolonieeigenschaften von Mycoplasma felis und M. gatae werden beschrieben und illustriert. Es wird vorgeschlagen, diese Eigenschaften zur Identifizierung dieser beiden Katzenmycoplasmen zu verwenden. Die Wirksamkeit der Methode, Mycoplasmen aus dem Schlund von Katzen mittelsfester und flüssiger Medien zu entnehrnen, wird einer Bewertung unterzogen. Rei dem Versuch, Mycoplasmen aus Tieren oder ihren Geweben zu isolieren, ist die Verwendung flüssiger Medien wichtig.     

Survival of Isospora suis oocysts under controlled environmental conditions

Isospora suis is a coccidian parasite infecting piglets soon after birth. While the gross epidemiology of I. suis is well known, little knowledge exists on the ecology of the oocysts. To study the development and survival of oocysts of I. suis under controlled laboratory conditions, known numbers of oocysts ( approximately 200 in each of 4 replicates) were exposed to all combinations of 4 relative humidities (53-100% RH) and 3 temperatures (20 degrees , 25 degrees , 30 degrees C). Determination of viability was based on morphological and fluorescent properties of the oocyst as well as on the permeability of the oocyst wall characterized by inclusion/exclusion of the fluorescent dye propidium iodide. The viability of the oocysts was studied over time by fluorescence and light microscopy until <5% of the oocysts were considered to be viable. The sporulation rate increased with temperature, however, the infective sporocyst stage was reached within 24h at all temperatures, while RH did not seem to affect sporulation. Results show a rapid reduction in viable oocysts exposed to high temperatures (25 degrees C and 30 degrees C) in combination with low relative humidities (53% RH and 62% RH), at which conditions oocysts died within 24h. Viability was higher when oocysts were exposed to higher relative humidities (75% RH and 100% RH) as well as a lower temperature (20 degrees C). However, even at 75% RH the oocysts died within 24-60 h at 30 degrees C to 20 degrees C, respectively, while the most favourable condition appeared to be 100% RH and 25 degrees C at which condition the percentage of viable oocysts decreased from 100% to 17% in 96 h. The results indicate that it may be possible to reduce the infection pressure of I. suis in modern sow herds by changing the environmental conditions and/or the management within the farrowing pens, and thereby increase animal welfare without relying on the use of routine medication.     

Evaluation of the 1996 NRC beef model under western Canadian environmental conditions

Two feedlot trials were conducted to evaluate the 1996 NRC beef model under western Canadian conditions. In the first trial, 144 Charolais- (304.6 +/- 16.3 kg) and 144 Hereford- (295.1 +/- 20.8 kg) cross steers were used, whereas the second trial used 88 Angus- (289.7 +/- 15.0 kg), 88 Charolais- (299.8 +/- 17.9 kg), and 88 Hereford- (291.1 +/- 20.9 kg) cross steers. Diets were based on barley silage, rolled barley grain, canola meal, and cereal straw and were analyzed according to the 1996 NRC methodologies. Animal performance and environmental data were collected for 24 pens of steers per trial for the backgrounding and finishing periods. Levels 1 and 2 of the 1996 NRC model were used to generate predictions of DMI and ADG for each pen. Results showed that actual finishing DMI was accurately predicted for Trial 1 and for the combined trials but not for Trial 2. Predicted ADG was lower (P < 0.05) than actual ADG for all feeding periods except Level 1 of the Trial 1 finishing period. All ADG residuals were significant (P < 0.05), indicating inaccurate prediction of ADG in all feeding periods. The 1996 NRC model consistently predicted that protein was not limiting gain. Further investigations and model refinement regarding animal energy requirements under cold weather conditions and effects of limit feeding are required to increase the accuracy of the 1996 NRC model in predicting animal performance.