一起猪呼吸道综合征的诊治

1发病情况2006年月4月份到7月份期间,福建省福清某猪场母猪存栏120头,全场存栏1300多头,在此期间共有35头母猪发病,其中3头母猪发生流产,32头母猪产死胎,死胎数大部份在怀孕100d以后,死胎数占产仔数1/3左右,母猪的发病率占总母猪数29.1%。在此期间共死亡哺乳仔猪250余头。保育猪发病率在50%左右,死亡率在30%左右。猪场以前没有免疫过猪兰耳病疫苗,猪瘟疫苗、猪伪狂犬疫苗、猪口蹄疫苗有正常免疫。通过笔者采取综合性措施很快控制疫情。2临床症状2.1母猪母猪发病时体温在40￣41.2℃,精神不振,采食量下降,外观母猪皮肤较以前苍白,个别表现黄疸…     

一起猪呼吸道综合征的诊治

1发病情况 2006年4月份到7月份期间。福建省福清某猪场母猪存栏120头．全场存栏1300多头，在此期间共有35头母猪发病．其中3头母猪发生流产。32头母猪产死胎，死胎数大部份在怀孕100d以后．死胎数占产仔数1／3左右。母猪的发病率占总母猪数29．1％。在此期间共死亡哺乳仔猪250余头。保育猪发病率在50％左右，死亡率在30％左右。猪场以前没有免疫过猪兰耳病疫苗。猪瘟疫苗、猪伪狂犬疫苗、猪口蹄疫苗有正常免疫。通过笔者采取综合性措施很快控制疫情。     

仔猪类圆线虫病的诊治报告

正仔猪类圆线虫病在我县临床并不少见,由于从外地引进仔猪,加之饲养条件差,又逢雨季,使得该病的发病率高达40%,造成很大的经济损失。现报告如下。1发病情况我县某猪场2005年7月从河北省购入仔猪683头,在购猪时,已进行猪瘟、丹毒双倍量免疫。全猪群于8月31日有5头发病,至10月20日左右,总发病达273头,发病率40%,死亡132头,死亡率19.3%。致死率49%,猪场兽医技术人员曾对该病猪     

猪高致病性猪蓝耳病的综合防制

正猪高致病性猪蓝耳病,是一种具有高度传染性的病毒性传染病,由古典型猪繁殖与呼吸系统综合症发生变异后的毒株所引起,临床上以母猪发热、厌食和流产、木乃伊胎、死产、弱仔等繁殖障碍以及仔猪的呼吸道症状和高度死亡率为特征。受感染种猪场的母猪流产、早产、死胎率可达20%以上,新生断奶仔猪死亡率可高达80%以上;种公猪感染后精液质量下降;育肥猪发病率高,死亡率低,但发病后生长缓慢,饲料报酬降低,康复猪可长期     

某规模化猪场副猪嗜血杆菌病的防制

<正>副猪嗜血杆菌病是由副猪嗜血杆菌(HPS)引起,在当前工厂化养猪生产过程中已成为常发病,该病情产生一方面受天气等外界因素的影响,另一方面同其他细菌病或病毒病共同作用而致。常以咳嗽、瘦小、关节炎、高热为主要病症,而且治疗效果不太显著,给猪场种猪销售带来一定的影响。江苏某猪场存栏母猪600头,2012年3月份,断奶后仔猪到育成舍阶段的仔猪发生该病,其中5号产房521头仔猪,发病率20%,通过诊疗,最后死亡率为8%。     

一起仔猪断奶后多系统衰竭综合征的诊治体会

<正>断奶仔猪多系统衰弱综合征(PMWS)是由猪圆环病毒Ⅱ型(PCV-2)引起的一种断奶后仔猪以全身性消耗为主要特征的新传染病,已在全世界范围内发生和流行。该病多发生于4～18周龄的猪,以8～12周最为常见,较少感染乳猪。受感染的猪群发病率约为2%～50%,病死率达到5%～100%。     

猪增生性肠炎的诊治

湘南某猪场1群仔猪爆发了一起以腹泻、拉酱油色稀粪,皮肤苍白为主的疫病,在200头仔猪中发病猪达152头,发病率达76%,死亡19头,死亡率占发病猪的12.5%。采取肌肉注射四环素和料中拌入支原净和金霉素治疗,效果良好,1周后疫病完全得到控制。     

仔猪葡萄球菌性皮炎的诊治

仔猪渗出性皮炎,又称为仔猪油性皮脂溢”或“猪油皮病”,是一种以急性全身性的皮脂溢出性皮炎为特征、具有高度接触性的传染病。该病病原是葡萄球菌,主要发生于5周龄内的仔猪,l周龄内仔猪发病率最高。死亡率为10%～90%,即使成活也会严重影响仔猪的生长发育,是规模猪场危害较大的一种传染病。现将一起仔猪发生葡萄球菌性皮炎的防治情况报告如下。1发病情况炉下某猪场饲养母猪412头,哺乳仔猪有2519头(212窝),保育猪2486头,育成猪2571头。2006年4—6月间,有79窝,共871头哺乳仔猪仔猪相继发生了一种油脂样皮炎的传染病,死亡92头。主要发生在l周…     

一起蓝耳病、圆环病毒Ⅱ病合并感染继发猪附红细胞体病、猪传染性胸膜肺炎的诊治

1发病情况 粤东某猪场存栏猪800多头(其中母猪82头),2004年4月初先后于育成猪舍的保育猪(1～3月龄)出现以咳嗽、气喘、发热、皮毛松乱或皮肤潮红、食欲不振或废绝为特征的病猪39头(其中死亡19头),发病率占该幢猪舍235头的11.06%,死亡率为发病猪的48.7%.发病初期作为一般感冒和猪肺疫而选用退热药及大量抗菌(如青霉素、链霉素、头孢氨苄、林可霉、氧氟沙星和磺胺类药等)进行治疗不但无效,且疫情进一步蔓延,母猪舍先后出现8头流产或产死胎,还有1窝23日龄的临断奶仔猪(11头)开始发病即2头母猪突然喘气死亡.原先发病之病猪,有的表现贫血、皮毛苍白或黄染,也有出现丘疹性皮炎.     

断奶仔猪爆发溶血性链球菌病的综合诊治报告

临沂市某猪场饲养自繁断奶仔猪２０８头，２００２年１０月初开始相继发生了一种以体温升高、神经症状及败血死亡为主的疾病。据统计本次共有６７头发病，发病率为３２％以上；死亡２３头，死亡率占发病猪只的３４％。给其造成一定的经济损失，我们接诊后通过临床检查和实验室检验等手段确诊为猪的溶血性链球菌病，并采取中西结合综合治疗措施控制了病情，取得满意效果，现将诊治情况报告如下。１发病情况据饲养人员介绍，２０８头仔猪刚断奶不久，日龄相差１～１０d不等，１０月３日全部进行了猪瘟、猪丹毒、猪肺疫三联苗的预防注射。１０…     

Regulatory costs on U.S. salmonid farms

The economic effects of the implementation of regulations on aquaculture farms in the United States, while of concern, are not well understood. A national survey was conducted of salmonid (trout and salmon) farms in 17 states of the United States to measure on‐farm regulatory costs and to identify which regulations were the most costly to this industry segment. The response rate was 63%, with a coverage rate of 94.5% of the U.S. production of salmonids. The regulatory system resulted in increased national on‐farm costs of $16.1 million/year, lost markets with a sales value of $7.1 million/year, lost production of $5.3 million/year, and thwarted expansion attempts estimated at $40.1 million/year. Mean farm regulatory costs were $150,506/farm annually, or $2.71/kg; lost markets with annual sales values of $66,274/farm; annual lost production of $49,064/farm; and an annual value of thwarted expansion attempts estimated at $375,459/farm. Smaller‐scale farms were affected to a disproportionately greater negative extent than larger‐scale farms. Per‐farm regulatory costs were, on average, greater for foodfish producers than for producers selling to recreational markets, but per‐kg regulatory costs were greater for those selling to recreational compared to foodfish markets. Regulatory costs constituted 12% of total production and marketing costs on U.S. salmonid farms. The greatest regulatory costs were found to be effluent discharge regulations. The majority of regulatory costs were fixed costs, but regulatory barriers to expansion precluded compensatory adjustments to the business in spite of growing demand for salmonid products. Results of this study show that the on‐farm regulatory cost burden is substantial and has negatively affected the U.S. salmonid industry's ability to respond to strong demand for U.S. farm‐raised salmonid products. Results also suggest that the regulatory system has contributed to the decline in the number of U.S. salmonid farms. While regulations will necessarily have some degree of cost to farms, the magnitude of the on‐farm regulatory cost burden on U.S. salmonid farms calls for concerted efforts to identify and implement innovative regulatory monitoring and compliance frameworks that reduce the on‐farm regulatory cost burden.     

Detailed monitoring of white spot syndrome virus (WSSV) in shrimp commercial ponds in Sinaloa, Mexico by nested PCR

WSSV has caused great losses to the global shrimp industry in recent years. This virus can infect shrimps asymptomatically. However, once the clinical signs are developed, mortalities can reach 100% in 3-10 days. PCR has been extensively used to detect WSSV in a specific and sensitive manner. Nested PCR is even more sensitive than single-step PCR and had been used for the detection of WSSV in asymptomatic populations. In this work, a detailed monitoring of WSSV by nested PCR in shrimp commercial ponds in Guasave County, State of Sinaloa, Mexico, is presented. Five ponds from two different farms were monitored for growth and presence of WSSV. At the beginning of the culture, ponds from both farms showed no or very slight WSSV presence. A 3-day period of rain occurred at both farms 10 and 14 weeks of culture for farms 1 and 2, respectively. At this time, WSSV was widely distributed in the shrimp populations of farm 1 according to nested-PCR data, although no visual symptoms were observed. In ponds of farm 2, WSSV was present at low level. However, the number of PCR-positive groups was drastically increased in both farms by nested and single-step PCR. Abrupt fluctuations in temperature and salinity were documented in farm 2 after the rain, which may have contributed to the increasing of viral load in the pond's shrimp populations. Twelve days after the rain period, estimated mortalities of 80% occurred in farm 1. Nevertheless, the study ponds at farm 2 culture continued normally for three more weeks and were harvested successfully (52% and 67% of survival for ponds 1 and 2, respectively). The removal of 40% and 50% of shrimp population 2-4 days after the raining period may have contributed to the thriving of the cultures. Analyses of the presence of WSSV in individuals of both sexes indicated that there is no preference for this virus to infect male or female shrimp. Also, no differences in weight were found between WSSV infected and non-infected individual shrimps, as well as nested-PCR positive against single-step PCR positive organisms. Nested PCR is more useful to monitor shrimp cultures than single-step PCR since it allows knowing how widely distributed the virus is in asymptomatically populations.     

Asian carp farming systems: towards a typology and increased resource use efficiency

Resource use efficiency in Asian carp farming systems is analysed based on a survey of 2493 farms of nine countries. Multivariate classification of farms by intensity and diversity identified six farm types: four types of specialized aquaculture farms at different levels of intensity, and two types of integrated agriculture–aquaculture systems. Pond‐based, specialized semi‐extensive systems (using mainly inorganic fertilizers and feeds of off‐farm origin), and integrated semi‐intensive systems (using feeds and fertilizer of both on and off‐farm origin) are by far the most common types, accounting for 59% and 27% of all farms respectively. Specialized semi‐extensive systems also show the highest protein and nutrient (N and P) use efficiencies, and among the highest labour use efficiency. Super‐intensive cage farms are less efficient in nutrient and labour use, but provide very high returns to land and capital investment. On average, the aquaculture components of integrated agriculture– aquaculture systems are less nutrient, land, and labour efficient than specialized semi‐extensive systems. Integrated semi‐extensive systems (using organic fertilizers of on‐farm origin) are particularly inefficient across all indicators. Hence in practice, gains in overall resource use efficiency through on‐farm integration with agricultural production are constrained by the relative inefficiency of the aquaculture subsystems on integrated farms. Although such systems can likely be improved, integration as such is not a panacea to increasing resource use efficiency. Wide variation in resource use efficiency within all systems indicates potential for substantial efficiency gains through improved management regardless of the fundamental choice of system.     

White spot syndrome virus epizootic in cultured Pacific white shrimp Litopenaeus vannamei (Boone) in Taiwan

White spot syndrome virus (WSSV) has caused significant losses in shrimp farms worldwide. Between 2004 and 2006, Pacific white shrimp Litopenaeus vannamei (Boone) were collected from 220 farms in Taiwan to determine the prevalence and impact of WSSV infection on the shrimp farm industry. Polymerase chain reaction (PCR) analysis detected WSSV in shrimp from 26% of farms. Juvenile shrimp farms had the highest infection levels (38%; 19/50 farms) and brooder shrimp farms had the lowest (5%; one of 20 farms). The average extent of infection at each farm was as follows for WSSV‐positive farms: post‐larvae farms, 71%; juvenile farms, 61%; subadult farms, 62%; adult farms, 49%; and brooder farms, 40%. Characteristic white spots, hypertrophied nuclei and basophilic viral inclusion bodies were found in the epithelia of gills and tail fans, appendages, cephalothorax and hepatopancreas, and virions of WSSV were observed. Of shrimp that had WSSV lesions, 100% had lesions on the cephalothorax, 96% in gills and tail fans, 91% on appendages and 17% in the hepatopancreas. WSSV was also detected in copepoda and crustaceans from the shrimp farms. Sequence comparison using the pms146 gene fragment of WSSV showed that isolates from the farms had 99.7–100% nucleotide sequence identity with four strains in the GenBank database – China ( AF332093 ), Taiwan ( AF440570 and U50923 ) and Thailand ( AF369029 ). This is the first broad study of WSSV infection in L. vannamei in Taiwan.     

A COMPARISON OF THE ECONOMIC PERFORMANCE OF OFFSHORE AND INSHORE AQUACULTURE PRODUCTION SYSTEMS IN KOREA

The economic performance of the current inshore rock bream aquaculture industry conducted in Yeosu, Korea was compared with a pilot commercial scale offshore aquaculture farm in Jeju, Korea. Data was collected from 12 inshore farms and two production cycles of the offshore farm for use in Monte Carlo simulations run over a ten year time horizon. Net present value was compared for the inshore farms and two survival rate scenarios for the offshore farm. The offshore farm is expected to have a higher survival rate if it can withstand tsunamis and avoid pollution, disease and red tide impacts that are prevalent inshore. When the offshore farm was modeled with its observed higher survival rate, its average net present value ($1,016,483) significantly outperformed the inshore farms average net present value ($182,153). In the second scenario, the offshore farm survival rate was lowered based on performance data from the inshore farms. Not surprisingly, given the higher investment costs, the offshore farm performed poorly in terms of average net present value ($-137,142) compared to the inshore farms when it no longer had the advantage of high survival rates.     

上海市规模化猪场猪瘟感染状况的调查

经对上海市12家规模化猪场猪瘟感染状况的调查,发现临床上主要表现母猪的繁殖障碍型猪瘟和育肥肉猪群的温和型猪瘟形式,病症上趋于非典型化。经ELISA检测,来自7个区县20个规模化猪场的不同生产阶段的猪群中,生产公母猪猪瘟带毒率最高,达23.5%,哺乳仔猪和保育猪分别为1.68%和2.52%,育肥肉猪为7.14%;对BVD带毒状况调查,仅在育肥肉猪中检出阳性2头,占0.84%,检测结果与猪瘟临床发病情况具有相关性。     

Long‐term epidemiological survey of Kudoa thyrsites (Myxozoa) in Atlantic salmon (Salmo salar L.) from commercial aquaculture farms

Kudoa thyrsites (Myxozoa) encysts within myocytes of a variety of fishes. While infected fish appear unharmed, parasite‐derived enzymes degrade the flesh post‐mortem. In regions of British Columbia (BC), Canada, up to 4–7% of fillets can be affected, thus having economic consequences and impacting the competitiveness of BC's farms. K. thyrsites was monitored in two farms having high (HP) or low (LP) historical infection prevalence. At each farm, 30 fish were sampled monthly for blood and muscle during the first year followed by nine samplings during year two. Prevalence and intensity were measured by PCR and histology of muscle samples. In parallel, fillet tests were used to quantify myoliquefaction. Infections were detected by PCR after 355 and 509 degree days at LP and HP farms, respectively. Prevalence reached 100% at the HP farm by 2265 degree days and declined during the second year, whereas it plateaued near 50% at the LP farm. Infection intensities decreased after 1 year at both farms. Blood was PCR‐positive at both farms between 778 and 1113 degree days and again after 2000 degree days. This is the first monitoring project in a production environment and compares data between farms with different prevalence.     

Hydrodynamic implications in and around a caged finfish farm and its implications on the dispersal of farm debris

One of the key factors in determining the accumulation of sediment and soluble nutrients within a lease is water movement. Water masses entering and leaving the farm determine the finfish ecosystem interaction. Understanding the hydrodynamic interaction with the farm is therefore key to understanding the potential ecological effects of individual farms. In addition, finfish farms are now being proposed in exposed offshore environments and have caused concern regarding their potential down stream impacts on currents and wave climate. Seven current meters, oxygen probes and CTD were deployed to examine the hydrodynamic interactions inside and outside a 270 m long Salmon farm in Newfoundland, Canada. Current meter results indicate that the finfish farm cages have a clear shadowing effect on the currents. Currents upstream were found to be considerably faster than those recorded downstream during the sampling period. Current speeds inside the farm were also found to be considerably slower than those found outside of the farm especially during high flow events. In situ observations of currents were found to be similar to those predicted by previous CFD and hydrodynamic modelling studies. Modeling was also undertaken to calculate the energy lost as currents enter and leave a series of fish cages. In comparison to the observed flow the model compares relatively well. Flow recorded downstream of the farm was observed to be in the range predicted by the model as was the flow recorded inside and outside the cages. Current speed downstream of the farm is clearly affected by farm orientation which has important implications for the dispersal of farm debris. Average oxygen saturation within the cages over the 5 day sampling period was 80.2 %± SD 5.7 %, compared to nearly 100 %, 20 m and 50 m from the farm site. Orientation of the farm may play some part in determining the location and amount of oxygen depletion within the farm. The farm also acts to push water from deeper in the water column up into the cages which has implications for farms situated in heavily stratified environments.     

Principal economic effects of cormorant predation on catfish farms

Substantial economic losses of farmed catfish to fish‐eating birds such as the double‐crested cormorant, Phalacrocorax auritus, continue to be reported on U.S. catfish farms. An economic analysis was conducted of the on‐farm effects of both the increased expenditures to scare fish‐eating birds from catfish farms and of the value of the catfish that were consumed by cormorants. A survey was conducted of U.S. catfish farmers in the Delta region of Mississippi and Arkansas, to obtain farm‐level data on expenditures to scare birds. Estimations of the lost revenue from catfish consumed by cormorants were developed from a concurrent study on cormorant distribution, abundance, and diet in the region. The economic effects of bird predation in terms of both fish consumption and management costs were evaluated across three farm sizes and nine catfish production practices. Catfish farmers spent on average $704/ha ± $394/ha to scare birds, making bird‐scaring costs one of the top five costs of raising catfish. The greatest cost components of scaring birds were manpower (39% of all bird‐scaring costs) and the variable and fixed costs of trucks used to scare birds (34% of all bird‐scaring costs). Losses were greater on hybrid than channel catfish fingerling ponds. Industry‐wide, the value of catfish losses averaged $47.2 million (range of $25.8–$65.4 million). Total direct economic effects (including both the increased costs to scare birds and the revenue lost from fish consumed by cormorants despite bird‐scaring attempts) averaged $64.7 million (ranging from $33.5 to $92.6 million). Profitability improved by 4% to 23% across the farm size/production strategies analyzed upon removal of the economic effects from bird predation, with greater effects occurring on smaller‐scale farms. One‐third of the farm size and production scenarios analyzed changed from being unprofitable to showing a profit in the absence of such negative economic effects associated with bird depredation. Overall, the combined effects of increased farm expenditures to scare birds from farms and the value of the catfish lost to predation by cormorants caused substantial negative economic effects on catfish farms.     

Characterization of intake and effluent waters from intensive and semi-intensive shrimp farms in Texas

Two commercial shrimp farms in south Texas were evaluated for influent and effluent water quality from June to October 1994. The intensive farm, Taiwan Shrimp Village Association (TSV) had an average annual yield of 4630 kg ha^?1 while the semi‐intensive farm, Harlingen Shrimp Farm (HSF), had a yield of 1777 kg ha^?1. The study had three objectives: (1) to compare influent and effluent water from the intensive and semi‐intensive shrimp farms, (2) to show which effluent water‐quality indicators exceeded allowable limits, (3) to indicate inherent problems in farms operated with water exchange and summarize how findings from this study led to changes in farms' management that limited potential negative impact on receiving streams. Water samples were collected and analysed twice a week for the TSV farm and once a week for the HSF farm. Samples were analysed for dissolved oxygen (DO), salinity, pH, ammonia‐nitrogen (NH₃‐N), nitrite‐nitrogen (NO₂‐N), nitrate‐nitrogen (NO₃‐N), total phosphorus (TP), total reactive phosphorus (TRP), five‐day carbonaceous biochemical oxygen demand (cBOD₅), total suspended solids (TSS) and settleable solids (SettSols). Most of the effluent constituents showed fluctuations throughout the sampling period often related to harvest activity. Effluent pH at TSV was lower than influent values but within the regulatory requirements set by Texas Commission of Environmental Quality (TCEQ), formerly known as Texas Natural Resource Conservation Commission (TNRCC). HSF effluent pH values were higher than its influent, but still within TCEQ limits. Effluent DO mean levels were generally below the regulatory daily mean requirement, with values at TSV often below those for influent. Effluent nutrient concentrations and net loads were generally higher at the intensive shrimp farm, with NH₃‐N mean concentrations above the daily mean set by the TCEQ on several occasions. Effluent TSS concentrations were higher than influent for both farms, with daily mean values above the TCEQ limit. The two farms presented similar TSS concentrations despite their different stocking densities. However, TSS total net load and net load per hectare were higher at the intensive farm. The semi‐intensive farm presented higher cBOD₅ concentrations and net loads despite its lower stocking density, with daily mean values above the TCEQ limit. The cBOD₅ net load at TSV presented negative values indicating higher load at the influent than at the effluent. Analyses showed no evidence of self‐pollution between influent and effluent at the two farms. The high feed conversion ratio (FCR) values (2.3 and 2.7 for the intensive and the semi‐intensive farm respectively) suggest that better feed management is needed to reduce nutrient and solid net loads release from the two farms. The data obtained from this study resulted in several modifications in design and management of the two farms that reduced the potential negative impact on receiving streams. A brief summary of the improvement in selected effluent water‐quality indicators at the intensive shrimp farm is provided.