施用竹炭对卷心菜叶绿素含量和荧光参数的影响

为探究人工施用竹炭对卷心菜叶绿素含量和荧光参数的影响,进而明确卷心菜的最适竹炭有机肥施用量,在田间试验条件下设置了无碳(CK)、中碳(MC)和高碳(SC)3个处理,对卷心菜莲座期和结球期的叶绿素含量及荧光参数进行测量研究.结果表明:(1)结球期的卷心菜叶绿素含量极显著高于莲座期(p0.01),且随着竹炭量的增加,两个时期的叶绿素含量变化趋势一致,从高到低依次为:MC,CK,SC.(2)结球期的卷心菜初始最小荧光Fo、初始最大荧光Fm、PSⅡ的最大光化学效率Fv/Fm,PSⅡ的潜在活性Fv/Fo、非光化学猝灭系数qN均低于莲座期,而PSⅡ实际光化学效率ΦPSⅡ、光化学猝灭系数qP高于莲座期,且随着竹炭量的增加,两个时期的这些参数均表现出一致的变化趋势,Fo和qN均呈"V"型变化,而Fm,Fv/Fm,Fv/Fo,ΦPSⅡ和qP均呈现倒"V"趋势,但对ΦPSⅡ和qP没有显著影响(p0.05).说明结球期的卷心菜光合作用高于莲座期;当竹炭量由CK增加到MC,有利于提高叶片叶绿素含量,增强光能利用率,减少植株热耗散,提高植株光合作用;但随着竹炭量进一步增加到SC,卷心菜叶片叶绿素含量降低,光能利用率减弱,热耗散增加,光合作用受到抑制,即中炭(MC)处理条件下,此卷心菜长势最优,表明中炭是该卷心菜生长的最适竹炭有机肥施用量.     

Theileria orientalis MPSP types in Australian cattle herds associated with outbreaks of clinical disease and their association with clinical pathology findings

Between September 2010 and November 2011, 350 EDTA blood samples were received from 73 Australian cattle herds, as cases suspected to be infected with Theileria orientalis. Beef cattle were predominantly affected, with Angus and Angus-crossbred cattle representing 48% of smear positive samples examined. DNA extracts were tested in conventional polymerase chain reaction (PCR) assays for genes encoding the p32, Ikeda, Chitose and Buffeli major piroplasm surface proteins (MPSP). PCR findings were compared with results of clinical pathology examinations of stained blood smears for parasitaemia and packed cell volume (PCV). PCR testing was much more sensitive than clinical pathology examinations in detecting T. orientalis infections, and concurrent testing of neat and diluted extracts gave significantly more PCR positive results than testing of neat extract alone. Significant associations and correlations were shown between PCR results of p32 and Ikeda assays with PCV levels indicative of anaemia, and with the level of parasitaemia estimated by smears. A high proportion of samples had concurrent Ikeda and Chitose infection, and significantly more clinical cases of theileriosis were associated with the Ikeda MPSP type as the sole infection, compared with sole infection with types Chitose or Buffeli. The findings indicate Ikeda type organisms were significantly associated with clinical parameters of theileriosis in cattle herds in eastern Australia, and that this type is most likely to be responsible for outbreaks of theileriosis experienced in affected Australian herds. In New South Wales, 11 of 14 regulatory districts yielded Ikeda positive samples, with five (Mid-Coast, Cumberland, Central North, Hume and Lachlan) containing 234/307 (76%) of the Ikeda positive samples.     

Brucellosis

Extract

Madam:- There is current discussion on the low leverl of this disease and the best way to finally eliminate it from New Zealand. Lest it be thought that the way is easy, the following case may make us all aware that the task is to be taken seriously. I was involved in July 1985 when a farmer complained concerning a company Leptospira vaccine.     

Topical anaesthesia alleviates short-term pain of castration and tail docking in lambs

Objective To investigate the effect of a topical anaesthetic formulation on pain alleviation, wound healing and systemic levels of local anaesthetic actives in lambs undergoing castration and tail docking. Design Three placebo-controlled and/or randomised experiments were conducted using three groups of Merino lambs (n = 62, 68 and 19) undergoing routine castration and tail docking. Procedure Surgical castration, with either surgical or hot-iron tail docking, was performed with and without the application of topical anaesthetic (Tri-Solfen®) or placebo. The effects of this procedure were compared with those of rubber ring castration and tail docking, and of the handled but unmarked controls. Wound pain was assessed using calibrated Von-Frey monofilaments over a 4-h period, pain-related behaviour was assessed over 5 h, wound healing was assessed at 14 and 28 days, and the plasma levels of lignocaine and bupivacaine were determined. Results Rapid and up to 4 h primary hyperalgesia developed following surgical castration and tail docking in the untreated and placebo-treated lambs. It was absent in the castration wounds, and significantly reduced in the tail-docking wounds, of the treated lambs. Hot-iron docking was associated with mild and transient secondary hyperalgesia, which was abolished by the topical anaesthesia. There was a significant reduction in pain-related behaviours in treated lambs, which were not significantly different in their behaviour to the sham-operation handled controls. Plasma lignocaine and bupivacaine levels were below the toxic thresholds in all tested lambs. Conclusion Topical anaesthesia alleviates wound pain and significantly reduces pain-related behaviours in lambs undergoing surgical castration plus surgical or hot-iron tail docking, without a negative effect on wound healing or a risk of systemic toxicity.     

A pathologic and toxicologic evaluation of veal calves fed large amounts of zinc

Tissues were examined from 26 male Holstein veal calves given large amounts of dietary zinc. All calves had been fed 706 micrograms zinc/g of milk replacer for 28 days before the first death occurred. Calves died naturally (14, group A) or were euthanatized (12, group B) after 23 days of feeding a lower concentration of zinc (150 micrograms/g). Average amounts of zinc in liver (wet weight) were 345.72 micrograms/g (group A) and 344.84 micrograms/g (group B). Mean kidney zinc concentrations were 219.0 micrograms/g (group A) and 252.38 micrograms/g (group B). Tissue manganese, copper, and iron levels were normal. Changes at necropsy included pneumonia, fluid digesta, and petechiae and infarcts in liver, kidney, and heart (as a result of bacterial infections). Histological changes that were directly attributed to dietary zinc intake were: marked atrophy and necrosis of pancreatic acinar tissue (group A); multifocal fibrosis of pancreatic acini (group B); multifocal renal cortical fibrosis with necrosis in convoluted tubules and loops of Henle, and with intratubular mineralization (groups A and B). Hepatic midzonal mineralization and fibrosis of the adrenal zona glomerulosa were seen in group B calves.     

Canine indolent nodular lymphoma

Sixty-six cases of indolent canine lymphoid proliferation were reviewed. Age ranged from 1.5 to 16 years (median 9.0 years). Dogs of 26 breeds, plus 13 of mixed breeding or unknown lineage, were represented. B-Cell lymphomas (CD79a+) predominated. Marginal zone lymphoma (MZL), the largest group, involved lymph node (33 cases) and spleen (13 cases), with both tissues involved in five of these cases. Follicular lymphoma (FL) involved lymph nodes (five cases), and mantle cell lymphoma (MCL) occurred as solitary splenic masses (three cases). Nodal CD3+ T-zone lymphomas (TZL) (10 cases), were included since they resembled late-stage MZL at the architectural level. Two cases of marginal zone hyperplasia (MZH) were included to aid in differentiation of early MZL. Clonality status was determined in 54 cases by analysis of immunoglobulin heavy chain (IGH) and T-cell antigen receptor gamma (TCRG) gene rearrangement. Clonal rearrangement of IGH was detected in 28 of 35 MZL cases (80%), four of four FL cases (100%) and three of three MCL cases (100%). Concurrent cross lineage rearrangement of TCRG was detected in six MZL and two FL cases. Clonal rearrangement of TCRG was documented in five of eight TZL cases (63%). Limited survival data obtained for 18 dogs indicated that the B-cell lymphomas (MZL, MCL, and FL) and the T-cell lymphoma (TZL) were associated with indolent behavior and long survival. Although to the authors' knowledge, the true incidence of canine indolent lymphomas is unknown, the tumors are not rare and may have been underrecognized. Recognition of their architectural features, routine application of immunophenotyping, and molecular clonality assessment should alleviate this.     

Use of posterior predictive assessments to evaluate model fit in multilevel logistic regression

Assessing the fit of a model is an important final step in any statistical analysis, but this is not straightforward when complex discrete response models are used. Cross validation and posterior predictions have been suggested as methods to aid model criticism. In this paper a comparison is made between four methods of model predictive assessment in the context of a three level logistic regression model for clinical mastitis in dairy cattle; cross validation, a prediction using the full posterior predictive distribution and two “mixed” predictive methods that incorporate higher level random effects simulated from the underlying model distribution. Cross validation is considered a gold standard method but is computationally intensive and thus a comparison is made between posterior predictive assessments and cross validation. The analyses revealed that mixed prediction methods produced results close to cross validation whilst the full posterior predictive assessment gave predictions that were over-optimistic (closer to the observed disease rates) compared with cross validation. A mixed prediction method that simulated random effects from both higher levels was best at identifying the outlying level two (farm-year) units of interest. It is concluded that this mixed prediction method, simulating random effects from both higher levels, is straightforward and may be of value in model criticism of multilevel logistic regression, a technique commonly used for animal health data with a hierarchical structure.