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JI Alawneh MA Stevenson NB Williamson N Lopez‐Villalobos 《Reproduction in domestic animals》2014,49(3):362-369
This was an observational study of 828 lactations in 542 mixed‐age dairy cows that calved seasonally in a single, pasture‐fed herd in New Zealand in 2008 and 2009. The study objectives were to: (i) document daily liveweight change (?LW) before and after observed oestrus for cows subsequently diagnosed pregnant or non‐pregnant and (ii) quantify the sensitivity and specificity of ?LW as a test for oestrus. The sensitivity and specificity of ?LW when combined with other commonly used oestrous detection methods was also evaluated. In cows that conceived as a result of service at detected oestrus, liveweight loss began 1 day before the day of detection and was greatest on the day of detection (?9.6 kg, 95% CI ?11.3 kg to ?7.8 kg; p < 0.01) compared with LW recorded 2 days before the day of detection. In cows that did not conceive to a service at a detected oestrus, the lowest liveweights were recorded 1 day before the day oestrus was detected (?4.3 kg, 95% CI ?7.7 to ?0.8 kg; p = 0.02) compared with LW recorded 4 days before the day of detection. The sensitivity and specificity of ?LW as a means of oestrous detection were 0.42 (95% CI 0.40–0.45) and 0.96 (95% CI 0.95–0.97), respectively. When ?LW was combined with tail paint and visual observation, the oestrous detection sensitivity and specificity were 0.86 and 0.94, respectively. Monitoring LW change holds promise to enhance the sensitivity and specificity of oestrous detection in combination with other oestrous detection methods. 相似文献
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Maqbool M Ali A Alderson PG Zahid N Siddiqui Y 《Journal of agricultural and food chemistry》2011,59(10):5474-5482
The composite effects of gum arabic (GA) (5, 10, 15, and 20%) and chitosan (CH) (1.0%) on the biochemical and physiological characteristics of banana fruits stored at 13 ± 1 °C and 80 ± 3% relative humidity (RH) for 28 days and afterward for 5 days at simulated marketing conditions (25 °C, 60% RH) were investigated. Significant (P ≤ 0.05) differences were observed for the entire GA plus CH treatments as compared to the control. However, the results showed that after 33 days of storage, the weight loss and soluble solids concentration of fruits treated with 10% GA plus 1.0% CH composite coating were 24 and 54% lower, whereas fruit firmness, total carbohydrates, and reducing sugars were 31, 59, and 40% higher than the control, respectively. Furthermore, the composite edible coating of 10% GA plus 1.0% CH delayed color development and reduced the rate of respiration and ethylene evolution during storage as compared to the control. Similarly, sensory evaluation results also proved the effectiveness of 10% GA plus 1.0% CH composite coating by maintaining the overall quality of banana fruits. Consequently, the results of scanning electron microscopy also confirmed that the fruits coated with 10% GA plus 1.0% CH composite edible coating had very fewer cracks and showed a smooth surface. These findings suggest that 10% GA plus 1.0% CH as an edible composite coating can be used commercially for extending the storage life of banana fruits for up to 33 days. 相似文献
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M. Barghchi P. G. Alderson 《The Journal of Horticultural Science and Biotechnology》2013,88(3):435-445
Proliferating shoot cultures were established from shoot tips and nodal bud segments excised from seedlings germinated aseptically and cultured on Murashige and Skoog medium supplemented with BAP plus NAA. Shoot tip necrosis occurred in some cultures. Cultured shoots were rooted in vitro using MS medium (half strength macronutrients) containing IBA for root initiation, followed by subculture onto hormone-free medium for root development. Rooted shoots were readily established in peat-based compost. 相似文献
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The effects of mechanical and chemical methods of removing or reducing apical dominance on the multiplication of Alstroemeria cultivars grown in vitro were assessed. Subculture of rhizome explants without aerial shoot or rhizome apices and of rhizome explants divided into single internodes with or without aerial shoots, significantly enhanced rhizome multiplication. Subculture of rhizome explants with only the aerial shoot or rhizome apices removed produced no significant differences. Addition of the plant growth regulators T1BA, thidiazuron, NAA, GA3 and paclobutrazol to culture media, with or without BAP, did not significantly change the numbers of lateral rhizomes, shoots or roots produced. Paclobutrazol, however, extensively changed explant morphology. 相似文献
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SummaryCuttings of the tropical hardwood species Triplochiton scleroxylon K. Schum. may be extremely difficult to root, depending on the physiological status of the parent plant and propagation conditions. This study examined the importance of xylem blockage in limiting the water supply to unrooted stem cuttings. Stem resistance was greatest in Node 1 cuttings (youngest node) of stock plants, and decreased basipetally. Resistance increased to a maximum, and water potential reached a minimum, 6 d after transfer to rooting medium.The primary site of blockage occurred within 1 mm of the stem base, suggesting an excision-induced wounding response. Histological studies revealed that gums of carbohydrate origin were deposited in some protoxylem elements near the stem base. The influence of these factors in determining cutting survival is discussed. 相似文献
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Summary The macrobroth dilution technique was used to test the in-vitro effectiveness of 4 commonly used antimicrobial agents against 23 Australian isolates and 7 overseas strains of Serpulina hyodysenteriae. Minimum inhibitory concentrations and minimum bactericidal concentrations were determined. The growth of 90% of isolates was inhibited by dimetridazole at a concentration of 4 μg/mL, and by tiamulin at 8 μg/mL Australian isolates resistant to both antimicrobial agents were identified. Lincomycin was less effective than these antimicrobial agents, with 90% of isolates requiring a concentration of 128 μg/mL for inhibition of growth, and 54% being susceptible at 64 μg/mL. Tylosin did not prevent the growth of the majority of S hyodysenteriae isolates tested, and 90% were resistant to concentrations of 128 μg/mL. Resistant isolates came from different geographical areas. Resistance was not related to overall genetic background of the spirochaetes, and was not correlated with the presence of plasmids or the serogroup of the isolates. 相似文献
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R. Alderson 《Aquaculture (Amsterdam, Netherlands)》1979,17(4):291-309
The growth of sole and turbot was followed in groups of fish exposed to constant unionised ammonia concentrations at pH levels both at and below that of normal sea water. Low pH levels were produced by the addition of carbon dioxide. Results for both species showed evidence for a threshold level of unionised ammonia below which little or no effect on growth was evident. This level was determined to be 0.066 mg N/l for sole and 0.11 mg N/l for turbot at 16°C, 34‰ salinity. The different pH conditions did not have any marked effect on these threshold levels.Above the threshold levels growth appeared to be depressed in a linear manner with increased unionised ammonia. The rate at which growth was depressed was greatest at the low pH levels for both species. The level at which growth ceased thus decreased from 0.77 to 0.38 mg N/l for sole and from 0.9 to 0.3 mg N/l for turbot, over the pH range from 7.9 to 6.9.The absence of disease and gill damage in the experimental populations is discussed. It is suggested that this and the tolerance shown by the fish, which is higher than is generally accepted for fish in high density culture, may be due to the clean environment in which the fish were held while under test. 相似文献