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Goodwin WA Keates HL Pasloske K Pearson M Sauer B Ranasinghe MG 《Veterinary anaesthesia and analgesia》2011,38(5):431-438
ObjectiveTo determine the pharmacokinetics and pharmacodynamics of the neurosteroidal anaesthetic, alfaxalone, in horses after a single intravenous (IV) injection of alfaxalone, following premedication with acepromazine, xylazine and guaiphenesin.Study designProspective experimental study.AnimalsTen (five male and five female), adult, healthy, Standardbred horses.MethodsHorses were premedicated with acepromazine (0.03 mg kg?1 IV). Twenty minutes later they received xylazine (1 mg kg?1 IV), then after 5 minutes, guaiphenesin (35 mg kg?1 IV) followed immediately by IV induction of anaesthesia with alfaxalone (1 mg kg?1). Cardiorespiratory variables (pulse rate, respiratory rate, pulse oximetry) and clinical signs of anaesthetic depth were evaluated throughout anaesthesia. Venous blood samples were collected at strategic time points and plasma concentrations of alfaxalone were assayed using liquid chromatography-mass spectrometry (LC/MS) and analysed by noncompartmental pharmacokinetic analysis. The quality of anaesthetic induction and recovery was scored on a scale of 1–5 (1 very poor, 5 excellent).ResultsThe median (range) induction and recovery scores were 4 (3–5) (good: horse slowly and moderately gently attained recumbency with minimal or no rigidity or paddling) and 4 (1–5) (good: horse stood on first attempt with some knuckling and ataxia) respectively. The monitored cardiopulmonary variables were within the range expected for clinical equine anaesthesia. The mean ± SD durations of anaesthesia from induction to sternal recumbency and from induction to standing were 42.7 ± 8.4 and 47 ± 9.6 minutes, respectively. The mean ± SD plasma elimination half life (t1/2), plasma clearance (Clp) and volume of distribution (Vd) for alfaxalone were 33.4 minutes, 37.1 ± 11.1 mL minute?1 kg?1 and 1.6 ± 0.4 L kg?1, respectively.Conclusions and clinical relevanceAlfaxalone, in a 2-hydroxypropyl-beta-cyclodextrin formulation, provides anaesthesia with a short duration of recumbency that is characterised by a smooth induction and satisfactory recovery in the horse. As in other species, alfaxalone is rapidly cleared from the plasma in the horse. 相似文献
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Oestrus detection error and conception rates after AI based only on secondary oestrus signs were evaluated in a high yielding, 24-h tie-stalled dairy herd with low fertility, using milk progesterone profiles. Oestrus detection was based on the secondary oestrus signs such as restlessness, swelling, congestion of vulva and clear mucus discharge. Sixty eight AI conducted after observing the secondary oestrus signs in 44 animals were included in the study. Of the 68 AI, 53 (77.9%) were conducted in the follicular phase, and 13 (19.1%) and 2 (2.9%) were carried out in the luteal phase and during pregnancy, respectively. The overall error in oestrus detection based on milk progesterone profiles was 22.1%. The oestrus detection error did not differ significantly among different secondary oestrus signs. None of the AI conducted in the luteal phase resulted in conception, whereas 20.8% of AI conducted in the follicular phase resulted in conception. No significant difference in the conception rates among the groups of cows with different secondary oestrus signs was shown. The high incidence of oestrus detection error in this study might have been caused by the detection of cows in oestrus based only on secondary oestrus signs due to the confinement of animals. In conclusion, there was a high incidence of heat detection error in the 24-h tie-stalled dairy herd and oestrus detection based only on secondary oestrus signs resulted in low conception rate. 相似文献
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One of the major problems of confection sunflowers is low seed set. We studied the relationship between seed set and the origin of pollen, either self or cross, and the effects of stigmatic sprays of calcium nitrate, boric acid and polyphenols on seed set. In a screen-house experiment, seed set was analyzed for three predetermined regions in the sunflower capitulum: distal, median and proximal. Cross-pollination combined with calcium nitrate or boric acid spray significantly improved seed set in the distal region compared with cross-pollination alone or with cross-pollination combined with self-pollination. Neither spray had a significant effect on seed set in the median or proximal regions. Cross-pollination of the proximal region only, with either fresh pollen or 24-h-old pollen, did not improve seed set compared with cross-pollination of the whole capitulum. We found no direct link between pollen germination on the stigma and seed set. However, each region of the capitulum responded differently to self- or cross-pollination. In two open-field experiments, stigmatic applications of calcium nitrate significantly increased seed set by approximately 9% compared with open pollination alone, while stigmatic applications of polyphenols significantly increased seed set by approximately 9% only once, suggesting that commercial yields may be increased by using similar applications. 相似文献
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Y.?CohenEmail author V.?Alchanatis Y.?Saranga O.?Rosenberg E.?Sela A.?Bosak 《Precision Agriculture》2017,18(5):801-822
Aerial thermal remote sensing can provide a means for collecting spatial plant water status data. Many studies have shown their potential in irrigation management but the adaptation of this technology is not straight forward. In this paper, knowledge accumulated in recent years on thermal imagery analysis methodology for water status mapping is summarized aiming at indicating alternatives to calculate the Crop Water Stress Index (CWSI) for commercial scale water status mapping. Based on literature overview, four forms of wet-baselines to calculate CWSI were selected, namely: artificial wet reference surface, two theoretical calculations and a statistical bio-indicator. These baselines were used to calculate CWSI based on multi-temporal aerial thermal images of cotton fields. CWSI based on a statistical bio-indicator and one of the theoretical wet-baselines provided the best correlations. It is argued though that the statistical one is preferable since it includes the plant characteristics and it is farmer-friendly. Based on bio-indicators, leaf water potential maps of three commercial fields were produced on several dates through the season. Water status spatial patterns were not static and the effect of static factors like sandy soil patches also changed through the season. The maps show the importance of in-season variability mapping for rational irrigation management. To improve current variable-rate irrigation, the concept of in-season irrigation management zones (IMZ) based on thermal-images should be considered and integrated with the delineation of static irrigation IMZ. 相似文献