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21.
C Friis E Erhardsen E B Madsen P Nielsen K Raun 《American journal of veterinary research》1991,52(8):1269-1273
Pharmacokinetic determinants of spiramycin and its distribution into the respiratory tract were studied in 2 groups of calves, 4 to 10 weeks old. Group-A calves (n = 4) were used to determine pharmacokinetic variables of spiramycin after IV (15 and 30 mg/kg of body weight) and oral administrations of the drug (30 mg/kg) and to measure distribution of spiramycin into nasal and bronchial secretions. Group-B calves (n = 4) were used to determine distribution of spiramycin into lung tissue and bronchial mucosa. Spiramycin disposition was best described by use of an open 3-compartment model. Mean (+/- SD) elimination half-life was 28.7 +/- 12.3 hours, and steady-state volume of distribution was 23.5 +/- 6.0 L/kg. Bio-availability after oral administration was 4 +/- 3%. High and persistent concentrations of spiramycin were achieved in the respiratory tract tissues and fluids. Tissue-to-plasma concentration ratio was 58 for lung tissue and 18 for bronchial mucosa at 3 hours after spiramycin administration and 137 and 49, respectively at 24 hours. Secretion-to-plasma concentration ratio was 4 for nasal secretions and 7 for bronchial secretions, and remained almost constant with time. Thus, spiramycin penetrates well into the respiratory tract, although the value in bronchial secretions is lower than that in lung tissues and bronchial mucosa. Calculations indicate that a loading dose of 45 mg/kg, administered IV, followed by a maintenance dose of 20 mg/kg, IV, once daily is required to maintain active concentrations of spiramycin against bovine pathogens in bronchial secretions. 相似文献
22.
P S Madsen 《Nordisk veterinaermedicin》1979,31(11):449-454
Milk somatic cell counting was carried out by Fossomatic and microscopically. In unpreserved milk samples Fossomatic counts increased by up to 100% during the first 24 hours after milking. During the next 24 hours the counts increased by 5% whereafter they remained stable until at least 80 hours after milking, when the samples were stored at 5 degress C. On microscopical counting using methylene blue for staining, the results were stable from shortly after milking. In counting, attention had to be paid to the fact that within the first 24 hours a certain part of the cells would stain but faintly. After preservation with potassium bichromate the Fossomatic counts increased more rapidly. Stable results were found 5--8 hours after preservation. The final level of the Fossomatic counts was found to be app. 10% higher in preserved than in unpreserved samples. A smaller increase was found by microscopic counting. The rise of the cell counts during the first 24 hours after milking is probably due to inadequate stainability of living cells with ethidium bromide, resulting in a certain part of them being recorded by the Fossomatic. During the first day the vitality of the cells diminishes whereby they become stainable and countable. This process in hastened by potassium bichromate treatment. 相似文献
23.
J D Olsen T E Anderson J C Murphy G Madsen 《Journal of the American Veterinary Medical Association》1983,183(5):538-543
Bur buttercup (Ceratocephalus testiculatus) has not been considered to be poisonous, but the sudden death loss of 150 ewes while grazing it prompted study of the plant. It was found that bur buttercup can be highly toxic to sheep, with a lethal dose being as little as 500 g of green plant for a 45-kg sheep. Clinical signs of bur buttercup poisoning are weakness, depression, diarrhea, labored breathing, anorexia, and occasional fever. Postmortem findings include inflammation and edema of the rumen; hemorrhage in the left ventricle of the heart; congestion of the lungs, liver, and kidneys; and excessive fluid in the thoracic and abdominal cavities. 相似文献
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Residual energy intake, defined as actual minus predicted energy intake during a production period, was estimated for each of 650 bull calves of 31 Holstein Friesian or Brown Swiss sires. Residual energy intake, measured under ad libitum feeding, had heritabilities similar to those of growth rate and energy conversion ratio with an estimate of approximately .3. Residual energy intake was related to average daily energy intake both phenotypically and genetically such that selection for decreased residual energy intake would lead to a decrease in daily feed intake. Such selection would also tend to increase carcass fatness (i.e., genetically fat animals are the most efficient). Residual energy intake estimated with and without correction for carcass composition were closely correlated. Thus, residual energy intake may be estimated without the knowledge of carcass composition in growing bulls of dual-purpose breeds. 相似文献
27.
Internal derangements in the human knee joint caused by meniscal lesions affecting joint function are known to have influence on local radionuclide uptake (Nicholas & Holder 1980, Mooar et al. 1987). To elucidate the joint reaction to minor meniscal lesions, not interfering with knee joint function, a model involving the avascular central part of the medial meniscus was used. Lesions in this area are known not to heal spontaneously (Heatley 1980, Veth et al. 1983). 相似文献
28.
The claimed low production of CH(4) by kangaroos and marsupials in general has been questioned because of a lack of data. The extent of their CH(4) production is of interest both from the point of view of discussing meat production of marsupials and as a basis for developing methods to reduce CH(4) production from ruminants. In the present experiment, the CH(4) production of 8 red-necked wallabies (Macropus rufogriseus) was measured of which 4 were fed 2 different diets in an open-circuit respiration chamber. These results were compared with a newly developed, inexpensive, and simple method that does not influence the behavior of the animal, and where the ratio between CH(4) and CO(2) is measured and used together with the calculated CO(2) to quantify the CH(4) production. The experiment demonstrated that the wallabies produce CH(4). However, the amount of CH(4) produced by these wallabies was between 1.6 and 2.5 L/d equivalent to 1.6 and 2.5% of GE or 2.2% and 3.5% of DE intake and 0.22 L/BW, kg(0.75). This is between 25 and 33% of what can be expected from ruminants fed the same diet. Based on the uneven release of CH(4) with time, it is most likely that the CH(4) is excreted through flatulence and not through breathing as is seen in ruminants. The experiments also showed that a reasonably accurate determination of the CH(4) production of a group of animals can be obtained by simply measuring the CH(4)/CO(2) ratio over a limited time span. This may represent the situation in a natural setting better than measurements in a respiration chamber. It was found that the CH(4)/CO(2) ratio in itself represents a reasonable prediction of the proportion of feed GE that is lost as CH(4), and that this method offers new opportunities for CH(4) measurements on a large number of animals. 相似文献
29.
Matthew D. Madsen Steven L. Petersen Bruce A. Roundy Bryan G. Hopkins Alan G. Taylor 《Strength and Conditioning Journal》2012,65(2):182-188
Soil water repellency can limit postfire reseeding efforts and thus increase the susceptibility of a site to weed invasion. We evaluated the effectiveness of wetting agents and simulated anchor chaining for improving seedling growth and survival in water-repellent soil, for the native perennial bluebunch wheatgrass (Pseudoroegneria spicata) and invasive annual cheatgrass (Bromus tectorum). Research was performed in a glasshouse, on 20-cm-diameter soil cores that were excavated from underneath burned Utah juniper (Juniperus osteosperma) trees. The experiment was arranged as a randomized split-plot design, with the two grass species sown separately under four soil treatments: 1) no treatment (control), 2) simulated anchor chaining (hereafter referred to as “till”), 3) wetting agent, and 4) till plus wetting agent. Soil water content was highest in the wetting agent treatment, lower for till, and lowest in the control. Overall, the response of bluebunch wheatgrass and cheatgrass was similar among treatments. At the conclusion of the study, wetting agent cores had twice as many seedlings as the control, while the till and control were similar. Despite a lower number of seedlings, tilling in general resulted in the same level of biomass as the wetting agent treatment. Overall, biomass in the till and wetting agent treatments was at least twofold higher than the control. No benefit was found in applying both till and wetting agent treatments together in comparison to just applying wetting agent. Because of a lack of correlation between glasshouse and field settings the results of this study need to be interpreted with caution. Our data may indicate that if cheatgrass is not already present on the site, anchor chaining or treating the soil with wetting agent can increase establishment of seeded species. 相似文献
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