Nutrition and feeding of the geriatric horse.

Little is known regarding nutrient requirements and feeding of geriatric horses, and more effort should be placed on this area of equine nutrition research. That which is known suggests that some geriatric horses may not have different requirements than other mature horses, whereas others affected by disease or poor dentition may have special nutritional needs. In general, rations for geriatric horses should be based on high-quality roughage supplemented with complementary minerals and vitamins. The need for additional energy aside from that provided by the forage can be supplied by adding energy concentrates, such as cereal grains or fat, to the ration. Processing techniques involving heat, such as pelleting and extruding, are advised when cereal grains are included in the ration so as to improve starch digestibility in the small intestine and avoid starch overload in the hindgut and it subsequent problem (ie, colic, laminitis). In addition, the environment in which geriatric horses are fed should be one that promotes ease of ration consumption and eliminates factors thar impair feed consumption, such as competition from other horses and the need to travel relatively long distances (eg, grazing marginal pastures). Finally, strict attention should be paid to the body condition of geriatric horses so as to evaluate adequacy of the ration and the general health of the horse.     

A Hierarchical Perspective to Woody Plant Encroachment for Conservation of Prairie-Chickens

Encroachment of Great Plains grasslands by fire-sensitive woody plants is a large-scale, regional process that fragments grassland landscapes. Using prairie grouse (Tympanuchus spp.) of conservation concern, we apply hierarchy theory to demonstrate how regional processes constrain lower-level processes and reduce the success of local management. For example, fire and grazing management may be locally important to conservation, but the application of fire and grazing disturbances rarely cause irreversible fragmentation of grasslands in the Great Plains. These disturbance processes cause short-term alterations in vegetation conditions that can be positive or negative, but from a long-term perspective fire maintains large tracts of continuous rangelands by limiting woody plant encroachment. Conservation efforts for prairie grouse should be focused on landscape processes that contribute to landscape fragmentation, such as increased dominance of trees or conversion to other land uses. In fact, reliance on local management (e.g., maintaining vegetation structure) to alter prairie grouse vital rates is less important to grouse population persistence given contemporary landscape level changes. Changing grass height, litter depth, or increasing the cover of forbs may impact a few remaining prairie-chickens, but it will not create useable space at a scale relevant to the historic conditions that existed before land conversion and fire suppression.     

Management practices to overcome the incidence of grass tetany

To minimize the incidence of grass tetany, winter pastures should be established on soils containing Mg-rich minerals, drainage should be improved on five-textured soils, legumes should be included in the sward and soil pH should be at least 5.5. Liming acid soils with dolomitic lime increases forage Mg by supplying Mg and by raising soil pH. Calcitic lime applications also can increase Mg availability to plants on soils with adequate Mg. Low rates of application of soluble Mg salts (less than 100 kg/ha of Mg) effectively increase Mg uptake from noncalcareous soils with low cation exchange capacity. Potassium levels in soils and plants should be kept in the lower range of recommended values. Nitrogen application should be regulated to provide the desired level of forage production. Nitrogen fertilizers, especially the nitrate form, stimulate plant Mg uptake if Mg is available in the soil. The most practical and cost-efficient method of supplementing dietary Mg intake is to provide free-choice Mg. Supplements must be palatable and placed in locations frequently used by cow herds. Including a high-energy feed in the supplement may at times increase its preventive effectiveness by increasing Mg absorption and reducing lipolysis. Regardless of the supplement formulation, Mg intake should be monitored on a regular basis, and formulation or management changes should be initiated if Mg consumption is below required levels. In severe grass tetany outbreaks, foliar application of Mg or administration of Mg via the drinking water may be warranted.     

Veterinary dairy herd health management in Europe: constraints and perspectives

The nature of veterinary work in dairy health management in Europe has changed over the past years and will change even more dramatically in the near future. The consumers and the media show increasing concern about animal welfare, safety of products of animal origin and traceability of animal products. Farmers in Europe have to produce under strict, often expensive and laborious regulations, while still commercially competing with farmers outside the EU and not subject to the same rules. Veterinarians should adapt their knowledge and skills to the new challenges and developments of the dairy sector. Dairy farmers nowadays ask for support in areas that go beyond clinical activities: environmental protection, welfare, nutrition, grassland management, economics and business management. Bovine practitioners should be able to advise in many different areas and subjects--that is the challenge to our profession. Veterinary education with regards to cattle health management should start with individual animal clinical work, which constitutes the basis of herd health advisory programmes. The bovine practitioner should then look beyond that and regard the herd as the unit. Each diseased cow or group of cows should be detected early enough to avoid financial losses or such losses should be prevented altogether by detecting and managing risk factors contributing to disease occurrence. Herd health and production management programmes represent the first level to optimise dairy farm performance. Expansions to that should further be considered, comprising both animal health and welfare issues, as well as food safety and public health issues. The latter could be addressed by quality risk management programmes following the HACCP-principles. Cattle veterinarians should follow recent developments and invest in new skills and knowledge in order to maintain their usefulness to the modern dairy farmer. Finally we are convinced that the cattle practitioner should evolve into this direction, otherwise the veterinarian as we know him will miss the train in the next years.     

Biotechnical measures for improvement of fertility in cattleMesures biotechniques pour améliorer la fertilité des bovinsBiotechnische massnahmen zur verbesserung der fruchtbarkeit beim rind

Improvement in fertility must first come from improved breeding management and only then from the use of biotechnical procedures. Short-term progestagen treatments, either alone or with ovarian stimulation, have the potential to induce cyclicity during the postpartum anoestrous period, thus reducing the intervals from calving to oestrus and conception and increasing litter size. Embryo transfer to induce twinning offers the possibility of increasing the proportion of cows calving by 7–8% and the calf crop by 30–40%. The measurement of circulating levels of hormones such as progesterone and oestrone sulphate allows the diagnosis of both single and twin pregnancy and may also be used to determine the causes of some infertility problems. Recent studies have indicated that early embryo death rather than fertilization failure is a major factor contributing to reduction in fertility level. Continued study in this area may provide a therapy for increasing embryo survival.     

Investigation planning and data gathering

The goal of outbreak investigation is the identification of the risk factors over which management has control; these factors are known as key determinants. The risk factor approach to disease causality is much more functional than simplistic theories such as agent causality. Many outbreaks, even of infectious disease, do not have simple microbiologic explanations. In the planning of an outbreak investigation, the most critical step is the identification of management procedures that have been found, by scientific studies, to influence risk of the type of disease present. During the investigation, specific disease data, rather than the client's impressions, should be collected so that temporal and risk group analyses may be performed. Performance evaluation should be conducted to determine the breadth of management systems involved and the duration of involvement. Management evaluation must be specific, comprehensive, and targeted by scientific studies, risk group and temporal analyses, physical examination, and laboratory diagnosis. The entire investigation--the planning, the data gathering, the sample collection--must be concentrated on identifying the ways in which management should be changed to restore equilibrium to a herd experiencing excessive losses due to disease.     

Chylothorax in cats: is there a role for surgery?

Chylothorax is a complex disease with many identified underlying causes including cardiac disease, mediastinal masses, heartworm disease and trauma. Management of this disease should be directed at identifying the cause, if possible, and treating the underlying disorder. In cats with idiopathic chylothorax, medical management is recommended initially because the condition may resolve spontaneously. Owners should be made aware of the potential development of fibrosing pleuritis in affected cats. When medical management is impractical or unsuccessful, surgical intervention should be considered. Surgical options include mesenteric lymphangiography and thoracic duct ligation, pericardiectomy, omentalisation, passive pleuroperitoneal shunting, active pleuroperitoneal or pleurovenous shunting, and pleurodesis. Of these, only thoracic duct ligation and pericardiectomy are preferred by the author because, if successful, the result is complete resolution of the chylothorax, thereby reducing the risk of developing fibrosing pleuritis. Omentalisation may be beneficial in some animals as adjuvant therapy, but this procedure may still allow fibrosing pleuritis to occur. Until the aetiology of the effusion in cats with idiopathic chylothorax is understood, the treatment success rate will be less than ideal. Future research needs to be directed at determining the pathophysiologic mechanisms underlying this disease in cats.     

Equine Metabolic Syndrome

Equine metabolic syndrome (EMS) is important because of its association with laminitis. Obesity and insulin resistance are two important components of EMS, and the underlying cause of this syndrome is likely to be enhanced metabolic efficiency. Affected horses are often referred to as “easy keepers” because they require fewer calories to maintain body condition, and enhanced metabolic efficiency is an inherent risk factor for EMS that may be genetically determined. Pony breeds, Morgan horses, and Paso Finos are predisposed to EMS, but this problem can be prevented through effective management. Overfeeding, abundant pasture grass, and inadequate exercise are risk factors that relate to modern management practices. Obesity and adiposity induce insulin resistance, and recent research suggests that this is the determinant of laminitis susceptibility in ponies. Increased plasma insulin concentrations are detected in most affected horses and ponies, so this serves as a useful screening test for EMS. Physical characteristics also should be examined because horses with EMS exhibit regional adiposity in the form of a cresty neck or abnormal adipose tissue deposits close to the tailhead. All horses with enhanced metabolic efficiency, obesity, or regional adiposity should be screened for EMS. The combined intravenous glucose−insulin test can be performed to diagnose insulin resistance in mildly affected horses and quantify insulin sensitivity. Most horses with EMS can be effectively managed by reducing caloric intake, decreasing the starch and sugar content of the diet, increasing exercise, and limiting or eliminating access to pasture, but medical therapy is warranted in select cases.     

Grazing Systems Do Not Affect Bird Habitat on a Sandhills Landscape

Grassland birds are declining faster than any other guild of birds in North America, in part because of degradation of their breeding habitat. Rangeland managers recommend increasing heterogeneity to improve biodiversity; however, on privately owned rangelands, beef production likely decreases heterogeneity on the landscape. One suggestion has been to use multiple grazing systems across a landscape to increase heterogeneity and provide benefits for avian biodiversity, but there is little research to support this recommendation. Thus, our goal was to examine heterogeneity and songbird abundance in relation to grazing systems used by private producers in a large, intact rangeland region. We measured vegetation structure and conducted avian surveys in the Nebraska Sandhills on 11 management units with five different grazing systems, including season-long continuous, deferred rotation, management intensive, dormant season only, and a fixed rotation. On each management unit we assessed the relationship between vegetation structure or songbird abundance and potential management effects, such as grazing system, stocking rate, and management intensity. Season of use and stocking rate were the most common sources of variation in vegetation structure and songbird abundance. Grazing system did not explain variation in vegetation structure or bird abundance, except for heterogeneity in live grass cover, litter cover, shrub cover, and abundance of field sparrows. Vegetation structure varied across the landscape we sampled, but the range of heterogeneity was narrow. Thus, managers should not assume that using a variety of grazing systems across a landscape will inevitably result in heterogeneity of vegetation structure. Rather, managers should focus on creating contrasting vegetation structure in large areas to increase large-scale heterogeneity. This may be achieved through the application of more extreme management practices (e.g., long-term heavy grazing and long-term rest or patch-burn grazing) so that a wider variety of vegetation composition and structure is available to support biodiversity.     

Nutritional factors of lameness and metabolic bone disease in cattle

Lameness in cattle has numerous causes, and many factors interact to interfere with normal locomotion. The nutrients that have been implicated are protein, energy, calcium, phosphorus, copper, manganese, selenium, zinc, and vitamins A, D, and E. The fact that several nutrients may be involved with the problem should not be overlooked. There may also be factors in the diet that interact with the nutrient (particularly with trace minerals) that must be considered. When congenital skeletal deformities are being investigated, the veterinarian should not overlook the nutrition of the dam during pregnancy. When recommending dietary changes, a veterinarian should be careful that new imbalances have not been created and that the producer is not adding nutrients to the diet other than those suggested.     

Meat inspection in New Zealand: prospects for change

Regulatory authorities are facing increasing challenges with respect to the newly-recognised public health risks associated with meat products. Meat inspection resources should be allocated according to their maximum ability to reduce food-borne hazards, rather than according to the classical rules of meat inspection. Scientific evaluation of routine post-mortem inspection procedures for each class of livestock, introduction of the Hazard Analysis Critical Control Point approach to process control, on-line testing for microbiological hazards and residues, and effective management of production, processing and inspection data are central to this process. The meat inspection system that has evolved in New Zealand reflects a response to non-scientific forces such as market requirements and industrial practices rather than scientific discipline. In the future, the daily routine of meat inspectors will be extended well beyond their current slaughterfloor responsibilities, and veterinarians will require specialist skills. Science should be the basis for international food regulation and policy concepts such as equivalence or mutual acceptance are achievable on this basis.     

Aboriginal Precedent for Active Management of Sagebrush-Perennial Grass Communities in the Great Basin

Until recently, most contemporary ecologists have ignored or diminished anecdotal historical accounts and anthropologists' reports about aboriginal fire in the Great Basin. Literature review shows that Indians practiced regular use of fire for many purposes, including the obvious reasons of increasing the availability of desired plants, maintaining habitats for animals used as food, and driving game during hunts. Historical accounts of prehistoric anthropogenic firing, inferences from fire-scar data, and data regarding annual production capability of representative sagebrush (Artemisia spp.)-perennial grass ecological sites indicate that prehistoric conditions were neither fuel- nor ignition-limited. According to many sources, this “active management” by Indians was widespread, significant, and more common than lightning-caused fires, resulting in mosaic vegetation patterns that subsequently moderated the behavior of “natural fires.” This interaction between Indian-burning and lightning fires may have strongly influenced the pre-Euro-American settlement vegetation of the Great Basin. At the very least, the landscape was a patchwork of areas altered by aboriginal people and areas shaped primarily by bio-physical processes. Based on this prehistoric precedent, current historically unprecedented conditions (fuel load and exotic weed invasion threats), and predicted climate change, contemporary active management of sagebrush-perennial grass communities is paramount. Restoration measures should be scientifically based and tailored to achieve ecological resilience and functionality in specific sites. Prescribed fire is not always ecologically appropriate or judicious, especially in Wyoming big sagebrush (A. tridentata spp. wyomingensis) communities, so managers should consider using other alternatives where an intentional low severity distubance is deemed necessary. Properly planned active management would disrupt fuel continuity for lighthning fires, ensure ecological process and successional integrity, and benefit multiple uses on a landscape scale.     

非淀粉多糖酶对仔猪早期生产性能和消化性能的影响

选用10头母猪生产的100多头仔猪 ,研究了玉米—豆粕型仔猪日粮中添加非淀粉多糖酶对仔猪早期生长性能和消化性能的影响。试验组在对照组日粮中添加120g/t非淀粉多糖酶。试验结果表明 ,添加非淀粉多糖酶使断奶仔猪蛋白质消化率提高9.67 %(P<0.05) ,有机物消化率提高15.40 %(P<0.05) ;添加非淀粉多糖酶对仔猪断奶前的生长无明显影响 ,但对断奶后0～14天的生长有显著的促进作用 ,可提高仔猪日增重10.40 %(P<0.05) ,提高窝重17.65 %(P<0.05)。试验结果同时提示断奶仔猪日粮中添加非淀粉多糖酶可有效地缓解仔猪断奶时的应激反应     

Parasitological risks--from animal husbandry to food and humans

Livestock management influences the infection risk with parasites. Extensive outdoor management increases the well being of the animals, but may also increase the infection risk with vector or intermediate host transmitted parasites. Several parasites can be transmitted by food. Trichinellosis again represents an increasing threat to human health by newly discovered species, new reservoir hosts and increasing meat import from eastern Europe. Tapeworm infections with Taenia saginata are more frequent than reported in the official statistics. The accurate prevalence and ways of distribution are not known. Toxoplasma gondii is a serious threat to pregnant, non-immune women and their babies. Cat faeces and pork meat are the most important sources of infection. Information, prevention of transmission and diagnostic examination of endangered persons are necessary to minimise the infection risk. Sarcocystis suihominis forms cysts in muscles of pigs, which may cause gastrointestinal symptoms after oral ingestion. In most cases however this protozoan parasite is not or only transiently harmful.     

应用DNA—荧光染料法评定瘤胃细菌细胞计数的研究

本研究应用瘤胃Succinogenes85细菌 ,用DNA荧光染料法探讨一种新的、简便而快速、无需厌氧操作的方法来评定瘤胃细菌计数。结果表明 ,加进DNA染料后 ,用超声波裂解细胞的时间不能低于30分钟 ,并且裂解后的样品在室温下平衡90分钟 ,对细菌的DNA含量没有影响。应用DNA荧光染料法测定的瘤胃细菌数与用细胞流动器测得的数值相比 ,从统计分析来看 ,没有显著差异(P<0.01)。     

Opposing offspring sex ratio variations with increasing age and weight in mouflon mothers (Ovis musimon).

There are two main theories explaining offspring sex biases in polygynous mammals. Trivers and Willard (1973) argue that mothers with greater reproductive resources should invest in the sex with the greater variance in reproductive success, usually sons. In contrast, because daughters in many polygynous mammals stay with their mother and compete with her for food, Local Resource Competition theory (e.g. Clark, 1978; Silk, 1983) predicts that the mothers with the greatest reproductive resources should invest in daughters. We investigated the strategy of sex allocation of a captive, outdoor population of 139 mouflon mothers, Ovis musimon, kept in a game state. A complex picture emerged in which, despite weight and body condition being correlated with age in female mouflons, mothers lambed more daughters with increasing age but also, within a given age, gave birth to more sons with increasing weight. Results may be useful in game management aimed at increasing the recruitment or quality of males in managed populations.     

Effects of final dilution rate, sperm concentration and times for cooling and glycerol equilibration on post-thaw characteristics of canine spermatozoa

This study re-evaluated a protocol for cryopreservation of canine semen. Semen from 4 beagle dogs was pooled, concentrated by centrifugation and adjusted to increasing sperm concentrations by adding back seminal plasma. The prepared or original semen was diluted with an extender (Egg yolk-Tris-citrate-glucose) and cooled to 4 degrees C (cooling), followed by a second dilution with the same extender including glycerol, equilibrated at 4 degrees C (equilibration), then stored in liquid nitrogen. The semen was diluted for frozen samples having a fixed sperm concentration with increasing dilution rates or for those having the reverse combinations. Various dilution rates of 2.5-10 folds or sperm concentrations of 0.25-2.5 x 10(8)/ml had no significant effect on post-thaw sperm characteristics. When cooling was done for different times (0-26 hr) with glycerol equilibration for 1 hr, post-thaw characteristics were better at 2 and 3 hr of cooling, while various times for equilibration (0-4 hr) with cooling for 3 hr had no effect. These results suggest that different dilution rates and sperm concentrations within the ranges tested may not affect the post-thaw sperm characterisitics and that sufficient time for cooling may be essential but a specific equilibration time may not necessarily be required.     

Early weaning beef calves.

Early weaning is a management practice that reduces grazing pressure on pastures by decreasing the nutrient requirements of cows. Calves that are weaned early are relatively efficient at converting feed to gain, and can weigh as much, or more than, calves allowed to remain with their dams until a conventional weaning age is reached. Balanced diets with excellent physical, chemical, and palatability characteristics are essential to stimulate intake and induce calves to perform at acceptable levels. Every effort should be made to minimize stress on calves during the weaning period. Early weaned calves, if exposed to high-starch diets at a young age, may be more likely to reach their genetic potential to marble than calves weaned at conventional ages.     

玉米青贮饲料乳酸菌检测培养基中放线菌酮添加量的优选

通过在MRS培养基、马丁培养基中添加放线菌酮0、5、10、20、40、80、160、320mg/L和640mg/L的5个试验,研究了玉米青贮饲料乳酸菌检测中放线菌酮在培养基中的适宜添加量。结果表明:添加放线菌酮40mg/L以上时能够极显著(P<0.01)抑制青贮玉米霉菌的生长。因此,确定40mg/L为检测或纯化培养青贮玉米乳酸菌时的适宜添加量;鉴于青贮玉米中乳酸菌是真菌的100倍以上,在乳酸菌培养时通过加大接种液的稀释倍数可达到避免样品真菌污染的目的。