Survey of equine castration techniques,preferences and outcomes among Australian veterinarians

Objectives

(1) To collect the perceptions of veterinarians performing equine castrations in Australia on techniques, preferences and outcomes, (2) to investigate veterinarian use and experience with the Henderson castrating instrument and (3) to investigate potential associations between demographics, castration methods and techniques, and complications.

Design

Online survey of members of the Australian Veterinary Association’s Special Interest Group, Equine Veterinarians Australia (EVA).

Methods

A link to the survey was included in the EVA e‐newsletter and practices on the EVA website were contacted by telephone and follow‐up email. Fisher’s exact test was used to determine associations between ligation and complications. A generalised linear model with a negative binomial family was used to determine associations between count response variables and categorical independent variables.

Results

Responses were obtained from 138 veterinarians (response rate, 13.1%) who performed 5330 castrations over 12 months. Castrations were most commonly performed in the field, on anaesthetised horses, using emasculators, via an open approach and without ligation of the spermatic cord. Estimated complications after use of emasculators were swelling (25%), haemorrhage (5%) and infection (5%). The Henderson instrument was used by approximately 10% of respondents and its use for castration was associated with fewer reports of postoperative swelling compared with emasculators (P = 0.002). Rates of evisceration with the Henderson and emasculator methods were comparable (0.43% and 0.9%, respectively).

Conclusion

Castration preferences varied widely among survey participants. Reported complication types and rates were comparable to those reported previously in other countries. Perceptions that the Henderson instrument was associated with less swelling should be investigated further via a prospective controlled investigation.     

microRNA-146a通过靶向MAPK4和Myosin Va基因调控羊驼黑色素细胞增殖、迁移

旨在研究microRNA-146a(miR-146a)对羊驼黑色素细胞增殖和迁移的调控及其分子机制。本研究使用双荧光素酶试验验证MAPK4和Myosin Va是miR-146a的靶基因;利用荧光定量PCR和蛋白质免疫印迹试验检测在羊驼黑色素细胞中过表达miR-146a对相关下游基因表达的影响;利用CCK8和Transwell检测miR-146a过表达对羊驼黑色素细胞增殖和迁移的影响。结果显示,与对照组相比,将miR-146a和MAPK4或Myosin Va共转染293T细胞,双荧光素酶活性分别极显著下降36%和30%(P<0.001);MAPK4和Myosin Va基因转录水平分别极显著下调67%和47%(P<0.001,P<0.01);蛋白质水平的表达量分别显著或极显著下调38%和69%(P<0.05,P<0.01);增殖和迁移相关的基因CREB、MITF、MLPH和Rab27a在转录水平和蛋白水平的表达均极显著下调(P<0.01,P<0.001);CCK8和Transwell结果显示,过表达miR-146a使羊驼黑色素细胞的增殖和迁移能力极显著下调(P<0.01)。综上所述,miR-146a通过靶向调控MAPK4和Myosin Va,使增殖和迁移相关的基因MEK1、CREB、MITF、MLPH和Rab27a的表达下调,从而对羊驼黑色素细胞的增殖和迁移起抑制作用。     

基于离散元法的深松作业玉米秸秆运动规律

东北垄作区玉米秸秆还田条件下,针对垄台播种带秸秆残茬易导致深松铲以及后续机具缠草堵塞和阻力增加等问题,建立深松铲-土壤-秸秆-根茬的离散元模型,分析仿真因素秸秆距垄台中心距离、秸秆与机具前进方向夹角、根茬状态（根茬中间切割、根茬一侧切割、根茬挑起和无根茬）和秸秆之间相互影响对深松作业过程中秸秆拨离垄台的影响。进一步探究深松铲作用下垄上秸秆运动规律并分析其扰动比阻（秸秆扰动力矩与深松铲阻力之比）。仿真结果表明：秸秆距垄台中心距离对秸秆位移中的水平侧向运动的影响最大;秸秆水平侧向位移随着秸秆与机具前进方向夹角增大呈减小趋势;根茬状态影响秸秆位移的主次顺序依次为：根茬挑起、根茬一侧切割、无根茬、根茬中间切割;当秸秆距垄台中心距离为60 mm时,秸秆之间相互影响对秸秆位移中的前进方向运动的影响最大;当秸秆距垄台中心距离大于60 mm,秸秆前进方向位移呈增大趋势。秸秆运动的力矩变化趋势为平稳变化,后产生峰值,最后又趋于平稳;影响秸秆力矩的主次顺序依次为：根茬状态、秸秆之间相互影响、秸秆距垄台中心距离、秸秆与机具前进方向夹角。深松过程中,秸秆扰动比阻在切割根茬一侧时达到最大值0.152 mm。田间对比试验结果表明,仿真模型得到的秸秆总位移、水平侧向、前进方向和垂直方向位移与田间试验值的误差分别为0.36%～9.67%、0.16%～12.31%、0.56%～10.11%和0.43%～4.63%,秸秆力矩的误差为0.16%～11.06%。研究结果可为深松铲设计以及优化提供一定的理论依据。     

基于离散元法的免耕深施肥分段式玉米播种开沟器研制

针对东北垄作深施肥免耕播种机上开沟器播种深度均匀性差、工作阻力大、土壤扰动大的问题,该研究利用离散元软件(EDEM 2.7)仿真分析不同类型破茬刀-施肥铲装置对土壤的作用机理,设计了一种分段式玉米播种开沟器。首先建立土壤-玉米根系-玉米秸秆离散元仿真模型,然后进行不同类型破茬刀-施肥铲装置离散元仿真试验,以回落土壤最大合外力的位置和方向为依据设计开沟器入土部分曲线,同时结合滑切原理设计开沟器未入土部分斜刃,最后根据土壤回落距离确定施肥铲和开沟器间距为374 mm。田间对比试验结果表明,分段式开沟器比尖角式开沟器、滑刀式开沟器、双圆盘式开沟器的播深变异系数分别降低了14.24%、27.31%、33.63%;工作阻力分别降低了27.56%、16.93%、1.23%;土壤扰动面积分别降低了11.67%、28.34%、49.34%。分段式开沟器播种深度均匀性高、工作阻力小、土壤扰动小,具有较优的作业效果。     

AFLP, ISSR and RAPD markers reveal high levels of genetic diversity among Lupinus spp.

The Lupinus genus includes a number of important crop species. The use of defined nucleotide sequences for the analysis of genetic diversity among these species has revealed modest levels of diversity. The aim of this study was to access AFLP, ISSR and RAPD markers to evaluate the genetic diversity among L. albus, L. angustifolius, L. cosentinii, L. hispanicus, L. luteus, L. mutabilis, L. pilosus and L. polyphyllus. Unexpectedly, low levels of genetic similarity were found (ranging from 0.205 to 0.432), regardless of the type of molecular marker used. Nevertheless, these techniques consistently showed a greater genetic similarity between L. pilosus and L. cosentinii, L. mutabilis and L. polyphyllus and among L. luteus, L. hispanicus and L. angustifolius, clearly separating the Old World from the New World species. Such low genetic similarity among Lupinus spp. is most unlikely to be due to differences in coding sequences but could be the result of a long diverging process concerning non‐coding regions, which would represent a very important proportion of these genomes.     

Low-voltage organic transistors on plastic comprising high-dielectric constant gate insulators

The gate bias dependence of the field-effect mobility in pentacene-based insulated gate field-effect transistors (IGFETs) was interpreted on the basis of the interaction of charge carriers with localized trap levels in the band gap. This understanding was used to design and fabricate IGFETs with mobility of more than 0.3 square centimeter per volt per second and current modulation of 10(5), with the use of amorphous metal oxide gate insulators. These values were obtained at operating voltage ranges as low as 5 volts, which are much smaller than previously reported results. An all-room-temperature fabrication process sequence was used, which enabled the demonstration of high-performance organic IGFETs on transparent plastic substrates, at low operating voltages for organic devices.     

基于CycleGAN-IA方法和M-ConvNext网络的苹果叶片病害图像识别

针对苹果叶片病害图像识别存在数据集获取困难、样本不足、识别准确率低等问题,提出基于多尺度特征提取的病害识别网络(Multi-scale feature extraction ConvNext, M-ConvNext)模型。采用一种结合改进的循环一致性生成对抗网络与仿射变换的数据增强方法(Improved CycleGAN and affine transformation, CycleGAN-IA),首先,使用较小感受野的卷积核和残差注意力模块优化CycleGAN网络结构,使用二值交叉熵损失函数代替CycleGAN网络的均方差损失函数,以此生成高质量样本图像,提高样本特征复杂度;然后,对生成图像进行仿射变换,提高数据样本的空间复杂度,该方法解决了数据样本不足的问题,用于辅助后续的病害识别模型。其次,构建M-ConvNext网络,该网络设计G-RFB模块获取并融合各个尺度的特征信息,GELU激活函数增强网络的特征表达能力,提高苹果叶片病害图像识别准确率。最后,实验结果表明,CycleGAN-IA数据增强方法可以对数据集起到良好的扩充作用,在常用网络上验证,增强后的数据集可以有效提高苹果叶片病害图像识别准确率;通过消融实验可得,M-ConvNex识别准确率可达9918%,较原ConvNext网络准确率提高0.41个百分点,较ResNet50、MobileNetV3和EfficientNetV2网络分别提高3.78、7.35、4.07个百分点,为后续农作物病害识别提供了新思路。     

Use of tilmicosin in a severe outbreak of respiratory disease in weaned beef calves

Severe respiratory disease, associated with seroconversion to bovine respiratory syncitial virus (BRSV), caused the death of two cattle and necessitated antibiotic treatment of 70 calves (rectal temperature of 39.6°C or greater) from a group of 96 (73%) during an 8-day period. Tilmicosin injection resulted in a reduction in median rectal temperature from 40.3°C to 39.2°C and 39.0°C for the first and second days after treatment. The rectal temperature was 39.5°C or lower in 72% (48 of 67) and 96% (64 of 67) of cattle 1 and 2 days after tilmicosin treatment, respectively. Ten cattle were re-treated with tilmicosin 6 to 16 days after the first treatment. Our study demonstrated that bovine respiratory syncytial virus infection could cause severe respiratory disease in a beef herd that had no previous history of BRSV-related disease. Secondary bacterial invasion after BRSV infection was controlled effectively by tilmicosin treatment but repeat antibiotic treatments were occasionally necessary due to bacterial re-infection of the respiratory tract.     

Severity and persistence of footrot in Merino sheep experimentally infected with a protease thermostable strain of Dichelobacter nodosus at five sites

Objective To test the hypothesis that ovine footrot associated with a thermostable protease strain of Dichelobacter nodosus undergoes self cure or is sustained as an annually recurring disease, depending on the environment.
Design and procedure Forty Merino sheep from a single blood line were infected with a protease thermostable strain of D nodosus a t each of five sites in Western Australia. Footrot lesions and microscopic evidence of D nodosus were recorded every fortnight for 2.5 years, supplemented by laboratory culture. Rainfall, soil and air temperature, pasture quantity and composition and soil types were also recorded. Flocks that apparently self cured were relocated to a more favourable site for footrot in the final spring season.
Results The maximum prevalence of feet with clinical footrot lesions was 80.6, 1.3, 14.4, 3.8 and 88.1% at the five sites. Severe footrot occurred for three consecutive spring seasons at one site that had clay loam soil and at least 3500 kg/ha total pasture dry matter annually. However, the infection was asymptomatic for up to 10 weeks between outbreaks. D nodosus was isolated from flocks for 2.5 years at only two sites, although there was microscopic evidence of the organism at other sites in the final year. A thermolabile variant (strain U6) of D nodosus was isolated from the two sites where footrot persisted.
Conclusion Depending on time and location, ovine footrot induced by a protease thermostable strain of D nodosus either self cured or persisted as annual outbreaks interspersed with periods of asymptomatic infection.     

Presence of Leptin and Its Receptor in the Hypothalamus,Uterus and Ovaries of Swine Females Culled with Distinct Ovarian Statuses and Parities

Leptin acts on energy metabolism, affecting reproductive functions through activation of its receptors in the brain and in reproductive organs. This study compared the presence of leptin and its receptor (ObR‐b) in hypothalamus neurons, endometrial glands and oocytes of culled swine females across ovarian statuses and parities. Immunohistochemistry was done in samples of uterus, ovaries and hypothalamus from 28 culled females, using polyclonal antibodies antileptin and ObR‐b. Immunolabelling was compared for sows categorized by parity at culling (0, 1, 2–4 and <4) and ovarian status (luteal and follicular phases of the oestrous cycle and with cysts). Immunolabelling for leptin and ObR‐b in neurons and oocytes was weaker in females with cysts (p < 0.05) than in those at the follicular phase. In endometrial glands, leptin immunolabelling was less intense in females with cysts (p < 0.05), but immunolabelling for ObR‐b was similar across ovarian statuses (p > 0.05). In sows culled with 2–4 parities, leptin immunolabelling in neurons and endometrial glands was more intense than in nulliparous females (p < 0.05). In comparison with sows culled at greater parities, ObR‐b immunolabelling for nulliparous females was less intense in endometrial glands and in oocytes (p < 0.05), but more intense in neurons (p < 0.05). Thus, in swine, the presence of leptin and ObR‐b varies across parities and is more intense in the uterus, ovaries and hypothalamus of females that were cycling before culling than in those having cystic ovaries.