感染猪放线杆菌(Ⅰ型)对猪红细胞免疫功能的影响

将24头健康DLY仔猪按性别、体重随机分为2组,采用鼻腔喷雾法一组接种生理盐水(对照组CG),另一组含3.8×107 cfu·mL-1猪放线杆菌(APP)的稀释液(试验组TG),研究感染APP对猪血常规指标和红细胞免疫功能的影响。结果表明,猪感染APP后,血液中的白细胞总数(WBC)、中性粒细胞数(GRA)、中间细胞数(MID)均极显著升高(P<0.01),淋巴细胞数(LYM)却极显著降低(P<0.01);TG的E-C3bRR(红细胞C3b受体花环)极显著高于CG组(P<0.01),E-ICR(红细胞免疫复合物花环)低于CG组,差异不显著(P>0.05)。试验表明,感染放线杆菌猪的防御能力增强,但其免疫力下降,并且红细胞免疫功能及清除循环血液中免疫复合物的作用增强。     

生猪屠宰环节微生物状况调查及建议

通过检测屠宰环节中生猪表皮微生物的菌落总数和生产用水卫生状况,对某屠宰企业的微生物污染情况进行了调查,旨在改善和提高屠宰企业卫生管理水平,提出改进意见,为完善企业HACCP体系提供理论基础。     

基于多种深度学习算法的田间玉米籽粒检测与计数

为快速准确获取玉米收获过程中遗失籽粒数信息,进行收割损失调节等管理,对比评估了单阶段和两阶段主流目标检测网络对田间玉米籽粒计数的性能。首先,利用RGB相机获取包含不同背景和不同光照的图像数据,并进一步生成数据集;其次,构建籽粒识别的不同目标检测网络,包括Mask R-CNN、EfficientDet-D5、YOLOv5-L、YOLOX-L,并利用所采集的420幅有效图像对构建的四种网络进行训练、验证、测试,图像数分别为200、40和180幅;最后,依据测试集图像的识别结果进行籽粒计数性能评价。试验结果表明,YOLOv5-L网络对测试集图像检测的平均精度为78.3%,模型尺寸仅为89.3 MB;籽粒计数的检测正确率、漏检率和F₁值分别为90.7%、9.3%和91.1%,处理速度为55.55 f/s,识别与计数性能均优于Mask R-CNN、EfficientDet-D5和YOLOX-L网络,并对具有不同地表遮挡程度和籽粒聚集状态的图像具有较强的鲁棒性。深度学习目标检测网络YOLOv5-L可实现实际作业中玉米收获损失籽粒的实时监测,精度高、适用性强。     

断奶应激对仔猪红细胞免疫功能的影响研究

为了研究早期断奶应激对仔猪红细胞免疫功能的影响,试验采用同窝杜×(大×长)三元杂交健康仔猪12只,分别于断奶前3天、断奶后3天及断奶后2周进行红细胞受体C3b花环试验、免疫复合物IC花环试验及血常规检验,观察断奶应激对仔猪红细胞免疫功能、红细胞数量及血红蛋白含量影响的动态变化。结果表明:断奶应激导致仔猪红细胞C3b受体花环率(C3bRR率)、红细胞总数和血红蛋白含量降低,IC花环率(ICR率)的变化明显。说明断奶应激可导致仔猪红细胞免疫功能下降,红细胞免疫功能低的仔猪更容易发生(断奶)应激性腹泻。     

Reliability in somatic cell count measurement of clinical mastitis milk using DeLaval cell counter

Somatic cell counts (SCC) measurements are typically performed using quantitative methods, such as the Breed method (Breed) and the Fossomatic method (FSCC). The DeLaval cell counter (DCC) developed recently is a quantitative somatic cell counter with a low initial cost and superior portability. However, since the DCC was specifically developed for measuring SCC of ≤ 4 × 10⁶ cells/mL milk from bulk tanks or individual cows, its reliability for estimating SCC that exceed this concentration has not yet been clarified. This study therefore examined whether it is possible to accurately measure SCC by diluting milk samples with initial SCC of 4 × 10⁶ cells/mL, as seen in clinical mastitis milk. We collected milk samples from 99 quarters of 99 Holstein cows with clinical mastitis. These milk samples were diluted 10‐fold with saline and thoroughly mixed before performing SCC measurement with the DCC. The correlation coefficients of SCC measured by the FSCC, Breed and DCC methods indicated strong correlations between each pair of methods. The findings showed that DCC can be used to identify bovine clinical mastitis milk and is useful as a quantitative SCC measurement device on farm sites.     

Numerical Methods in Marine Ecology

In order to elucidate the taxonomic status of the melanistic, girdled lizard, Cordylus cordylus niger, occurring in the Cape Peninsula and the Saldanha Bay area, South Africa, character variation among populations of the C. cordylus complex in the section of the Cape Province south of 32°3C latitude and west of 19°30' longitude was analysed. Variation for 92 external morphological characters at 54 localities was determined. Distinct patterns of interlocality variation were observed in only eight characters, but interestingly, these patterns were concordant in all eight cases. The observed patterns are interpreted as indicating that three phenotypic forms of the nominate species occur in the south-western Cape, namely a coastal melanistic form (= C. c. niger), occurring in insular and peninsular situations along the coast; a montane melanistic form occurring at relatively high altitudes along the western section of the Cape Fold Mountains; and the typical form (= C. c. cordylus), occurring commonly along the coastal lowlands, but also further inland at some places.     

Milk production increase following treatment of Dutch dairy cattle with thiabendazole

Summary

In a trial involving 542 dairy cattle on 28 farms, 276 were treated once with thiabendazole within two days of calving. The treated group showed an average increase in milk yielded over the non‐return group of 229.8 kg during the subsequent lactation.

In the treated group, total milk fat production was increased over that of the controls by 7.4 kg per cow; milk protein was increased by 6.9 kg per cow. All treatment parameter differences were highly significant at the 1% level of probability.     

天冬氨酸对脂多糖刺激断奶仔猪生长性能、血细胞分类计数和血液生化指标的影响

本试验旨在研究天冬氨酸(ASP)对脂多糖(LPS)刺激断奶仔猪生长性能、血细胞分类计数和血液生化指标的影响。试验选用24头断奶仔猪,分为对照组、LPS组、LPS+0.5%ASP组(0.5%ASP)、LPS+1.0%ASP组(1.0%ASP)。结果表明:0.5%和1.0%ASP可缓解LPS刺激导致的日增重的降低(P<0.05);注射LPS 4 h后,0.5%或1.0%ASP可显著缓解LPS刺激导致的淋巴细胞比例、血小板数量的降低和嗜酸性粒细胞比例的升高,增加红细胞平均血红蛋白(HGB)浓度(P<0.05);注射LPS 24 h后,0.5%和1.0%ASP可显著缓解嗜中性粒细胞数量、嗜中性粒细胞比例的升高和淋巴细胞比例的降低(P<0.05);0.5%或1.0%ASP可显著缓解LPS刺激引起的谷丙转氨酶、谷草转氨酶、碱性磷酸酶、尿素氮、血糖的升高和谷丙转氨酶/谷草转氨酶的降低(P<0.05)。结果显示,ASP缓解了LPS刺激所导致的生长抑制和应激反应。     

Has the optimum time for faecal nematode egg count reduction testing in sheep in New Zealand changed?

Abstract

AIM: To determine what, if any, changes have taken place in the optimum time, for undertaking faecal egg count reduction tests (FECRT) in sheep in New Zealand.

METHODS: A comparison was made between the numbers and types of nematode genera adequately represented for testing purposes (faecal nematode egg count (FEC) of >50 epg) in initial FECRT case submissions to a veterinary laboratory in New Zealand, during two 4-year periods, in 1992–1995 and 2006–2009.

RESULTS: Although there were some minor differences between them, the seasonal patterns of occurrence remained basically the same for all parasite genera in both datasets, with their individual peak periods of representation occurring during February to May in all instances. Not surprisingly, this period of maximum seasonal occurrence for each parasite genus also coincided with those months of the year when the greatest numbers of worm genera were adequately represented for faecal nematode egg count reduction (FECR) testing.

CONCLUSIONS: The results of this study indicate that the optimum time for conducting FECRT in sheep in New Zealand continues to be during the late summer-autumn months of February to May. However, they also reaffirmed that even during this optimal period there are still likely to be many occasions when relatively few nematode genera may be sufficiently well represented for satisfactory FECR testing. Accordingly, veterinary practitioners ought to be aware that, in order to obtain a complete picture of the resistance status of all worm genera on a particular property, such testing may need to be carried out on more than one occasion.