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排序方式: 共有98条查询结果,搜索用时 18 毫秒
1.
Johnson M Mackintosh CG Labes RE Taylor MJ Wharton DA 《New Zealand veterinary journal》2003,51(2):93-98
Aim: To discover whether cross infection between red deer (Cervus elaphus) and cattle is possible with either a bovine isolate of the cattle lungworm, Dictyocaulus viviparus, or with a cervine isolate of the lungworm, Dictyocaulus eckerti which is thought to be maintained primarily in deer. Method: Twelve cattle and 12 red deer were reared parasite-free from birth. At 3-4 months of age, half of each species (n=6) were experimentally infected with D. viviparus and the other half with D. eckerti. The course of infection was monitored for 34 days, after which the animals were slaughtered and the lungs removed to assess levels of infection. Results: Faecal larval counts demonstrated that patent Dictyocaulus infections occurred in all groups. At necropsy, adult worms were found in the lungs in all groups except the cattle that were infected with D. eckerti. The largest numbers of adult worms were found in the red deer infected with D. eckerti. Conclusion: It was demonstrated that both cattle and red deer could be infected with either D. viviparus or D. eckerti. However, D. eckerti larvae that originated from deer established more successfully in deer and D. viviparus larvae that originated from cattle established more successfully in cattle. 相似文献
2.
The effects of weaning on beef calves of different ages were investigated. Forty male and 40 female calves were either weaned at 6 (W6, n = 40) or 8 (W8, n = 40) months of age. The vocalization activity and behaviors (feeding, lying and standing/walking) were observed during the first 3 days following weaning. Body weight was recorded at 6 and 8 months and 2 weeks following weaning. W6 animals vocalized more often than W8 calves and females more than males on day 1 (P < 0.05). The vocalization activity decreased at a higher rate in W8 than in W6 from days 1 to 3. On day 2, W6 calves spent less time lying and more standing/walking than W8 calves (P < 0.05). The behaviors did not differ between males and females. The average daily gain after weaning did not differ between weaning ages (P > 0.05), but W8 calves gained more from 6 to 8 months of age. In conclusion, weaning distress was more pronounced in W6 than in W8 calves. W8 calves also had a superior growth performance during 6 to 8 months of age. The effect of the calves' sex was less pronounced. Therefore, it is recommended to wean beef calves later than 6 months of age. 相似文献
3.
Temperature signals contribute to the timing of photoperiodic growth cessation and bud set in poplar
Bud set, the cornerstone delimiting the seasonal growth period in trees, is the dynamic net result of the often photoperiod-controlled growth cessation and the subsequent bud formation. Here, we show that in hybrid poplar, the critical day length for growth cessation and the duration of bud formation each vary with local climatic conditions in identical genotypes. The detailed dissection of bud set suggests temperature as one additional environmental factor that modifies the sensitivity to day-length signals at growth cessation and influences the duration of bud formation in poplar. The ability of perennial plants to integrate additional environmental signals with photoperiod signaling may add to short-term acclimatization to the predicted longer growing seasons in future climates. 相似文献
4.
Caris-Veyrat C Schmid A Carail M Böhm V 《Journal of agricultural and food chemistry》2003,51(25):7318-7325
The aim of this study was to produce in vitro oxidation products of lycopene, which could be possible in vivo metabolites. An oxidation of lycopene with potassium permanganate gave a range of lycopene degradation compounds resulting from the oxidative cleavage of one or two carbon-carbon double bonds. Eleven apo-lycopenals/ones and six apo-carotendials were obtained and tentatively characterized by HPLC-DAD-MS. Apo-11-lycopenal and apo-8,6'-carotendial were isolated and characterized by (1)H NMR for the first time. Lycopene was submitted to an oxidation by atmospheric oxygen catalyzed by a metalloporphyrin, a model system of the active center of cytochrome P450 enzymes. (Z)-Isomers, monoxides, and cleavage compounds of (E)-lycopene were formed. We propose a mechanism of oxidation of lycopene by this system. 相似文献
5.
Martin J Schmidt Antje Wigger Sebastian Jawinski Tanja Golla Martin Kramer 《Veterinary radiology & ultrasound》2008,49(5):472-476
Ultrasonographic evaluation of the spine, especially of the spinal cord, has been rarely reported in dogs. The atlanto-occipital junction provides a small acoustic window through which examination of the craniocervical transition can be performed. Normal sonographic findings of this region in 10 normal brachycephalic dogs are presented and compared with sonographic findings from 25 Cavalier King Charles Spaniels with the caudal occipital malformation syndrome. Sonographic findings were compared with magnetic resonance imaging findings to determine the extent of cerebellar herniation and syringohydromyelia. Cerebellar displacement into the foramen magnum was clearly identified sonographically; however, syringohydromyelia was not discernable due to bone overlay. 相似文献
6.
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8.
Carl-Christian Gelfert Antje Lptien Nicole Montag Rudolf Staufenbiel 《Research in veterinary science》2009,86(3):529-532
Seeing the fact that farm managers in Germany feed anionic salts to transition cows once daily, this study set out to evaluate whether the effects on the acid–base status (ABS) and calcium excretion in urine would persist throughout the entire day beyond this feeding practice. Eleven non-lactating, non-pregnant, Holstein–Friesian-cows with a rumen fistula were administered 2Eq of calcium chloride (CaCl2/five cows) or calcium sulfate (CaSO4/six cows) once daily for a period of 1 week. At day 7, blood and urine samples were taken every 4 h starting at 06:00 a.m. before feeding the anionic salts, and then ending at the same time the next day. Feeding anionic salts to the cows induced metabolic acidosis in both of the groups. The changes tended to be greater in CaCl2-cows. After 12 h, the acidosis lessened and the initial values were reached after 24 h. The CaCl2-cows, however, still showed signs of compensated metabolic acidosis. The results of the present study showed that feeding anionic salts once daily confined the risk of an interrupted effect of the anionic salts on the acid–base status as well as calcium metabolism after 12 h. 相似文献
9.
Heba Salama Marc Lösche Antje Herrmann Martin Gierus Ralf Loges Ulf Feuerstein 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(1):23-34
Abstract Water-soluble carbohydrates and fibre fractions are important traits that influence forage utilization by the ruminant. Little is known about the quality variation among perennial ryegrass genotypes within the same maturity group or between near-isogenic diploids and tetraploids. The current study was carried out in the form of two experiments on two successive years (2006–2007) in three sites in Northern Germany. The main aim was to investigate the variation in nutritive value that could be attributed to differences in maturity among 20 intermediate heading perennial ryegrass genotypes or to differences in ploidy between near-isogenic diploids and tetraploids. Results of the first experiment revealed significant variation among the 20 tested genotypes in the investigated quality parameters that were consistent with the discovered variation in the maturity of the genotypes determined in terms of their Mean Stage by Count (MSC). In the second experiment, few but consistent significant differences were detected between near-isogenic diploids and tetraploids. The tetraploid derivatives had always significantly higher water-soluble carbohydrate content and lower neutral detergent fibre (NDF), acid detergent fibre (ADF) and acid detergent lignin (ADL) than their near-isogenic diploid parents. 相似文献
10.
Zusammenfassung Die physiologische Alterung der Pflanzknollen durch Lagerung bei überoptimalen Temperaturen (jahresunterschiedlich 16–29,5°C,
1988–90 vor dem Pflanzen abgekeimt, 1991 vorgekeimt wie Kontrolle) führte im Vergleich zur vorgekeimten Kontrolle im Mittel
von 25 Sorten in allen Versuchsjahren zu einer Verminderung der Bestandesdichte und des Ertrages. Eine Gruppe von Sorten erwies
sich in allen Jahren als relativ tolerant gegen die Alterung, eine andere als signifikant empfindlicher, dazwischen lag ein
breites Mittelfeld mit zum Teil erheblichen Schwankungen in den Jahren. Die Reaktion der Sorten zeigte keine Beziehung zu
ihrer Reifegruppe und ihrer Keimintensit?t, dagegen war die sortentypische Ertragsdepression nicht sehr eng, aber signifikant
mit dem Schwund w?hrend der Lagerung korreliert.
Summary Seed tubers were stored at above optimal temperatures. Mean temperatures varied during test years from 16 to 29.5°C (in 1988–1990 tubers desprouted before planting; in 1991 chitted tubers as in control; Table 1). This procedure of physiological ageing of seed tubers resulted in reduced plant density and lower yield compared to the chitted control in every year of the test period (average of 25 cultivars). The emergence was significantly delayed as compared to the control in all years (Table 2). Assessed for yield, the cultivars Désirée, Sanetta, Astilla and Andra showed a significantly higher degree of tolerance to warm storages (>80%, when compared to the control) than the cultivars Arkula, Dorisa, Karlena and Koretta (<25%; Table 3). Between these two extremes there was a large number of intermediate levels of tolerance, a result of fluctuating reactions of various cultivars to changing conditions in the years of the test period (Fig. 1). No correlation could be found between the cultivars' reactions and their maturity group or their sprouting behaviour. There was, however, for each cultivar a significant negative correlation between loss in weight through transpiration and respiration and plant density and yield (r=−0.55 and −0.54; Table 4). Plant density and yield were closely correlated (Table 4). The regressions between loss of plants and reductions in yields show that after seed tuber storage at higher temperatures a reduced yield must be expected even when plant density is not reduced (loss of plant 0%; Fig. 2). With complete stands, the use of physiologically aged seed tubers that were desprouted before planting (1988–1990) resulted in a reduction of yield of 17–20%; when old seeds were chitted as in control a loss in yield of 15% was calculated.相似文献