What can mathematical models bring to the control of equine influenza?

Mathematical modelling of infectious disease is increasingly regarded as an important tool in the development of disease prevention and control measures. This article brings together key findings from various modelling studies conducted over the past 10 years that are of relevance to those on the front line of the battle against equine influenza. The Summary is available in Chinese – see Supporting information.     

The Potch System: An approach to the management of semi‐arid grasslands in southern Africa

A host of grassland management systems have been published and recommended. Whereas earlier approaches to grassland management emphasized the systematic resting aspect, the systems published since 1966 have tended to stress the degree of utilization of the grassland sward. In an attempt to accommodate the periodic dry periods that are so typical of the semi‐arid grasslands of western Transvaal, the Potch system of management was evolved. It aims at the development of a fodder reserve, firstly by delaying the commencement of summer grazing, and secondly, by allowing prolonged periods of absence in the grazing rotation. High utilization grazing within the concept of controlled selective grazing is prescribed. This approach was tested and demonstrated over a period of five years in an experiment comprising 240 beef breeding cows. It appeared that generally, summer grazing only commenced after the third week of November, and that the mean period of occupation amounted to 20 days, with a period of absence of 87 days. A conception rate of 85% of all the cows and heifers mated, was achieved. A stocking rate of 0.53 LSU ha^?1 could be maintained in an area where the general grazing capacity is 0.33 LSU ha^?1.     

The Friesian horse breed: A clinical challenge to the equine veterinarian?

The Friesian horse breed is a beautiful breed for showing, riding and driving. However, some clinical problems seem to have a higher incidence in the Friesian breed compared to other breeds and this raises suspicions that these clinical entities may have a genetic basis.     

Cartilage matrix changes in the developing epiphysis: early events on the pathway to equine osteochondrosis?

REASONS FOR PERFORMING STUDY: The earliest osteochondrosis (OC) microscopic lesion reported in the literature was present in the femorotibial joint of a 2-day-old foal suggesting that OC lesions and factors initiating them may arise prior to birth. OBJECTIVE: To examine the developing equine epiphysis to detect histological changes that could be precursors to OC lesions. METHODS: Osteochondral samples from 21 equine fetuses and 13 foals were harvested from selected sites in the scapulohumeral, humeroradial, metacarpophalangeal, femoropatellar, femorotibial, tarsocrural and metatarsophalangeal joints. Sections were stained with safranin O and picrosiruis red to assess cartilage changes and structural arrangement of the collagen matrix. RESULTS: Extracellular matrix changes observed included perivascular areas of paleness of the proteoglycan matrix associated with hypocellularity and, sometimes, necrotic chondrocytes. These changes were most abundant in the youngest fetuses and in the femoropatellar/femorotibial (FP/FT) joints. Indentations of the ossification front were also observed in most specimens, but, most frequently, in scapulohumeral and FP/FT joints. A cartilage canal was almost always present in these indentations. The vascular density of the cartilage was higher in the youngest fetuses. In these fetuses, the most vascularised joints were the metacarpo- and metatarsophalangeal joints but their cartilage canals regressed quickly. After birth, the most vascularised cartilage was present in the FP/FT joint. Articular cartilage differentiated into 4 zones early in fetal life and the epiphyseal cartilage also had a distinct zonal cartilage structure. A striking difference was observed in the collagen structure at the junction of the proliferative and hypertrophic zones where OCD lesions occur. CONCLUSION: Matrix and ossification front changes were frequently observed and significantly associated with cartilage canals suggesting that they may be physiological changes associated with matrix remodelling and development. The collagen structure was variable through the growing epiphysis and a differential in biomechanical properties at focal sites may predispose them to injury.     

Serological testing—An alternative to boosters?

The issue of the duration of immunity, particularly for the modified live viral components of veterinary vaccines, has been a significant part of the recent vaccination debate. One manufacturer has increased the recommended booster interval for these components to 3 years give name and another now states 'up to 4 years' immunity. There remain many unanswered questions regarding this duration of immunity (DOI). Studies suitable for data sheet claims are time consuming and costly and can only be performed in laboratory dogs under tightly controlled conditions. Evidence from rabies serology testing in the UK shows that the response of individual animals to routine vaccination is highly variable. Much of the published field evidence on the persistence of antibody titres originates from North America, where vaccination strategies and reservoir species differ from Europe. Quantifying the effect of exposure to field virus on the maintenance of immunity in these studies is impossible, and little is known of the circulation of virus in unvaccinated dogs and wild mammals throughout Europe. If owners or vets are concerned about revaccination one option is to assess the need for each booster by performing a blood test. There is some published evidence of the relationship between antibody titres and protective immunity, and tests are available to measure responses to individual viral components of the routine canine and feline vaccines. It must be remembered that most commercial tests to assess immunity only measure antibodies, which are only one aspect of the immune response to vaccination. It is therefore possible that animals without or with low antibody titres are in fact protected. Serological tests are an option if owners are unwilling to have their animal boostered without evidence that it is needed. However, the cost of these tests is likely to exceed that of booster vaccination for the foreseeable future.     

Textbook Analysis——Learning to Speak:An English Video Course

This thesis proposes the evaluation of the textbook-An Eglish Video Course on the basis of analyzing the students and conducting interviews among related teachers and students.     

Is metoclopramide an alternative to tramadol in management of post-operative pain? An experimental study

In this study, metoclopramide was compared with other pharmacological agents for preventing post-operative pain. Sixty Sprague-Dawley male rats, weighing 310-345 g were included in the study; 1 cm surgical incision, including skin, facia, and muscle was made to the plantar surface of rear foot of all anaesthetized rats. Rats were randomized into four groups. In group 1 (group S) 2 cm3 saline, in group 2 (group M) 2 cm3 metoclopramide (5 mg/kg) in group 3 (group T) 2 cm3 tramadol (45 mg/kg), in group 4 (group M+T) half doses of group M and group T was given intraperitoneally. Post-operative pain was assessed after 2 h, first and second days of incision. Post-operative pain scores were found to be significantly lower in group M, group T and group M+T when compared with the control group. But there was no significant difference between these groups. We concluded that metoclopramide, with low cost, fewer side-effects and being significantly effective for preventing post-operative pain, can be an alternative to tramadol.     

Trichomoniasis in finches from the Canadian Maritime provinces — An emerging disease

Trichomoniasis was diagnosed in multiple incidents of mortality in wild purple finch (Carpodacus purpureus) and American goldfinch (Carduelis tristis) in the Canadian Maritimes. Birds exhibited regurgitation, emaciation, and hyperplastic oropharyngitis, ingluvitis, and esophagitis. Trichomonas gallinae was identified by histopathology and polymerase chain reaction (PCR). Trichomoniasis (trichomonosis) is an emerging disease in wild finches of eastern Canada.     

Pathogenesis of osteochondrosis dissecans: How does this translate to management of the clinical case?

Osteochondrosis (OC) is the most prevalent developmental orthopaedic disease in the horse. It is a complex disorder because of the interplay of factors that influence the formation of lesions and the ensuing natural healing process, the end result of which determines clinical outcome. The early pathogenetic mechanism of OC has long remained elusive, but recent research has provided compelling evidence for vascular disturbances leading to areas of ischaemic necrosis in the subarticular growth cartilage as the primary event. The aetiological factors that influence the process of the development of lesions are many and comprise both genetic and environmental factors. The genetic background of OC (dissecans) is highly complex with quantitative trait loci associated with some form of OC found on not fewer than 22 of the 33 chromosomes of the horse, and different manifestations and locations of OC having probably different genetic backgrounds. The environmental factors can be divided into nutritional factors and factors influencing the biomechanical loading of joints. Feeding large quantities of easily digestible carbohydrates is a clear risk factor and also the availability of sufficient copper for mares in the last part of pregnancy is important. Factors influencing the biomechanical loading of joints include the exercise regimen of foals, paddock size and roughness of terrain, and conformation. Equine OC is rarely a life‐threatening disease and the prognosis of (surgical) treatment is good to very good. However, the impact on economics of the equine industry and on horse welfare is large. This impact can only be lessened by the judicious management of both horse breeding and horse husbandry. Some of the measures that would alleviate the burden of OC conflict with (commercial) pressures from the industry and a balance between human‐imposed breeding and performance goals and the interest of the animal itself should be sought.