Large strongyles. Recent advances

This review cites recent advances in the knowledge pertaining to infections of large strongyles in equids. Emphasis is placed on Strongylus vulgaris and attention is focused on pathogenesis of clinical manifestations of infections and treatment and control, including chemotherapy of migrating larvae and drug resistance.     

Ascarids. Recent advances

P. equorum is a common and ubiquitous parasite that persists for many years in stables and on pasture in spite of good hygiene and anthelmintic control programs. Foals are usually infected early in life. During the migratory phase of the infection, clinical signs include coughing and a nasal discharge followed by depression and unthriftiness as the worms mature in the gut. Some foals die as a result of intestinal impaction or rupture. Patency is established around 3 months of age, and fecal egg counts may rise to very high levels. From 6 months of age onwards, the ascarid burden diminishes as the foals become immune. Patent infections are seldom found in mature horses and, when present, they tend to be of low magnitude. Preventive measures are aimed at treating foals frequently enough to prevent the development of a large mass of ascarids in the intestine. This is achieved by a 6-weekly dosing regimen using an anthelmintic with proven and reliable efficacy against P. equorum.     

Recent advances in avian virology.

Selected, recent research on the following avian diseases, and their causative viruses, has been reviewed: chicken anaemia, infectious bursal disease, turkey rhinotracheitis, avian nephritis, fowlpox, influenza, infectious bronchitis and turkey enteritis.     

Recent advances in inhalation anesthesia.

Both desflurane and sevoflurane offer theoretical and practical advantages over other inhalation anesthetics for horses. The lower solubility of both agents provides improved control of delivery and helps to counteract the confounding influence of the voluminous patient breathing circuit commonly used for anesthetizing horses. The lower solubility should account for faster rates of recovery compared with the older agents; whether or not the quality of recovery differs remains to be objectively evaluated in a broad range of circumstances. The pharmacodynamic effects are, in large part, similar to those of isoflurane (e.g., low arrhythmogenicity) but with some differences. For example, desflurane may be overall more sparing to cardiovascular function (especially during controlled ventilation) compared with isoflurane and sevoflurane, which are roughly similar. Respiratory depression with both new agents is equal to or more depressing than isoflurane, suggesting the use of mechanical ventilation, especially in circumstances of prolonged management (i.e., hours of anesthesia). Both new anesthetics, not surprisingly, are expensive. From this point there are some agent-unique considerations. The anesthetic potency of both agents is less than that of isoflurane, which influences the cost of anesthesia, but also places an upper limit on inspired oxygen concentration (of particular concern with desflurane). Both agents require new vaporizers, but because of the high boiling point and steep vapor-pressure curve of desflurane, new technology was required. This translates into more costly equipment, adding to the cost of desflurane use. In addition, electricity is necessary for the new desflurane vaporizer to function, which limits its portability and adds additional practical considerations in its clinical use. On the other hand, desflurane strongly resists degradation both in vitro and in vivo, but in vitro degradation of sevoflurane by CO2 absorbents may produce renal injury. This may be true especially in association with low fresh-gas inflow rates (used to reduce the cost of using the new agent), and university based practices, where prolonged anesthesia is common.     

Recent advances in Neospora and neosporosis.

Neospora caninum has emerged as a major cause of abortion in cattle in many countries. This paper reviews recent advances in the life cycle and biology of Neospora with the emphasis on bovine neosporosis. The role of the recently discovered oocyst stage of N. caninum in the epidemiology of neosporosis is discussed. Progress made in serologic diagnosis of N. caninum infection is discussed. There is no vaccine for preventing Neospora-induced abortions in cattle or to prevent oocyst shedding in dogs.     

Recent advances in small animal genetics.

The whole genome sequence of the dog is complete, and partial sequencing of the cat genome is underway. Sequences allow the molecular basis for inherited diseases to be more easily determined, leading to development of DNA tests to verify carrier and affected states as well as potential gene therapy for the treatment of those diseases. To help veterinarians provide genetic services to their clients, the molecular genetic tests currently available are listed in this article. In addition, cloning of small animals is now available to clients on a commercial basis. Information about the cloning process and possible health issues in clones are discussed.     

Recent advances in respiratory conditions in cattle.

The study of cattle respiratory diseases during the last decade show that several observations made in the late 1960s are still relevant today. Many of these diseases are shared with other countries in Europe, but the developments discussed will be examined with the respiratory disease problems that occur in Britain in mind. The new information is dealth with as it applies to (i) structure, function and immunology of the lungs (ii) diseases of calves indoors (iii) diseases of young animals grazing, (iv) diseases of adult animals indoors and (v) diseases of adult animals grazing.     

类胡萝卜素的研究进展

自然界中类胡萝卜素种类繁多,按其结构不同可分为胡萝卜素和类胡萝卜素含氧衍生物两大类。β-胡萝卜素是类胡萝卜素家族中的典型代表,可分裂形成两分子的维生素A,是动物体所必需的胡萝卜素。类胡萝卜素分子中重要的共同结构是都含有一个带有9个双键异戊二烯的链,在链的两端各有一个β-紫萝酮环,此环可能以异构型、取代型和开环型的形式存在。链中双键共轭,双键的数目,可能表明其抗氧化的能力。     

甘露寡糖应用研究进展

甘露寡糖作为一种新型微生态添加剂 ,具有吸附肠道病原菌和发挥免疫调节作用的双重功效 ,从而达到提高动物的生产性能。1　甘露寡糖的来源甘露寡糖 (Mannos -oligosacccharides ,MOS) ,是从富含甘露寡糖的酵母细胞壁中通过酶解法提取出来的磷酸化的葡甘露聚糖蛋白复合体 ,是甘露低聚糖的俗称。它广泛存在于魔芋粉、瓜儿豆胶、田菁胶及多种微生物细胞壁内 (葡甘露寡糖 ) ,目前商品用甘露寡糖主要通过酶解法进行生产。大量研究表明 ,不同来源的甘露寡糖在结构上有差异 ,如研究较多的魔芋甘露寡糖是由分子比为1∶1 5的葡萄糖和甘露糖残基通…     

Recent advances in the treatment of vaccine-associated sarcomas.

This article reviews the background information about vaccine-associated sarcomas followed by diagnostic procedures essential to understand how to determine the extent of the primary and metastatic tumor as well as to understand the general health of the patient. It also addresses the importance of understanding the nonmedical needs of the client who is faced with this perplexing problem.     

Recent advances in the field of doping detection.

Patterns of doping in Britain have on the whole changed from the use of CNS stimulants and depressants to therapeutic substances, or to accidental doping by feeding contaminated food or food supplements. Progress in detection and identification is largely a result of improvements in separation and isolation, especially by gas chromatography, together with the introduction of mass spectrometry. Radiommunoassay and high performance liquid chromatography promise to be important techniques in the future, especially in detection of anabolic steroids and corticosteroids.     

Equine strongyles. I. Development of anthelmintic resistance

Small strongyles (cyathostomes) that are resistant against anthelmintics have become a major problem in equine medicine in the recent years. In many European countries benzimidazole-resistant cyathostomes are widespread and are now present in well over 50% of equine populations investigated. In contrast, resistance against ivermectin has not been reported despite its widespread use in the recent years. Optimising the frequency of treatments based on quantitative faecal monitoring is of great importance to preserve remaining anthelmintic efficacy.     

Epidemiology of strongyles in ponies in Ontario.

The transmission of strongyles among 54 Shetland-cross mature ponies was examined from May 30 to November 22, 1983 when the ponies were on pasture and over the ensuing winter when they were in loose housing. Fecal and pasture herbage samples were taken fortnightly through the pasture season and periodically thereafter. Three foals born and reared on pasture were weaned and removed from pasture, two in early August and one in mid-September, and housed for a period before necropsy. Daily maximum and minimum air temperature and total precipitation were recorded. The mean fecal strongyle egg count was highest in the spring and early summer and lowest over the winter. Few larvae were found on the herbage in late May and their numbers were near zero by the third week in June. Subsequently, the numbers increased, were highest from late August through to mid-October and then declined and were low over the winter. Few strongyles were found in two foals removed earlier in the season, and many in the one later. The transmission of strongyles appeared to occur, therefore, principally from mid-summer to mid-fall.