Major Advances in Milk Marketing: Government and Industry Consolidation

Federal dairy programs have been instituted to assist dairy farmers in marketing their milk. Milk marketing licenses were issued for city markets in 1933 during the depression. Federal Milk Orders replaced licenses in 1937 with enactment of the Agricultural Marketing Agreement Act. Low prices returned in the late 1940s and Congress passed the Agricultural Act of 1949 creating the support program for milk. Congressional involvement in milk marketing was minimal until passage of the 1977 Farm Bill. A support price adjustment to seek favorable political responses from farmers resulted in higher prices and ultimately higher production. Large expenditures and burdensome supplies caused Congress to make major changes to both programs. Other milk marketing programs have evolved from Congressional actions, including export and promotion programs. The exiting and consolidation of the dairy processors and producers has lead to a reduction in the number of marketing orders.

Major Advances Associated with Reproduction in Dairy Cattle

The purpose of this overview is to review some of the major advances in reproductive technologies, and how they may be applied to meet the challenge of enhancing reproductive efficiency in the high-producing dairy cow of the 21st century. The current population of high-producing dairy cows is considered to be subfertile, as characterized by low pregnancy rates and high rates of embryonic mortality. Coordinated systems of reproductive management have been developed based upon a thorough understanding of the endocrine, cellular, and molecular factors controlling ovarian and uterine function. These systems will partially restore herd reproductive performance. Advances in other reproductive technologies offer possibilities for wider use of superior germplasm. Technologies such as sexed semen, cloning, transgenesis, and preimplantation genetic diagnosis offer the potential to enhance the influence of superior animals on production of food for human consumption. However, at this time, additional research is needed to counteract the higher rates of embryonic and fetal mortality associated with some of these technologies. Furthermore, use of genomics, proteomics, and bioinformatics in the study of reproduction will undoubtedly provide investigators with a greater understanding of the limitations to efficient reproductive processes in the subfertile lactating dairy cow.

Major Advances Associated with Environmental Effects on Dairy Cattle

It has long been known that season of the year has major impacts on dairy animal performance measures including growth, reproduction, and lactation. Additionally, as average production per cow has doubled, the metabolic heat output per animal has increased substantially rendering animals more susceptible to heat stress. This, in turn, has altered cooling and housing requirements for cattle. Substantial progress has been made in the last quarter-century in delineating the mechanisms by which thermal stress and photoperiod influence performance of dairy animals. Acclimation to thermal stress is now identified as a homeorhetic process under endocrine control. The process of acclimation occurs in 2 phases (acute and chronic) and involves changes in secretion rate of hormones as well as receptor populations in target tissues. The time required to complete both phases is weeks rather than days. The opportunity may exist to modify endocrine status of animals and improve their resistance to heat and cold stress. New estimates of genotype x environment interactions support use of recently available molecular and genomics tools to identify the genetic basis of heat-stress sensitivity and tolerance. Improved understanding of environmental effects on nutrient requirements has resulted in diets for dairy animals during different weather conditions. Demonstration that estrus behavior is adversely affected by heat stress has led to increased use of timed insemination schemes during the warm summer months to improve conception rates by discarding the need to detect estrus. Studies evaluating the effects of heat stress on embryonic survival support use of cooling during the immediate postbreeding period and use of embryo transfer to improve pregnancy rates. Successful cooling strategies for lactating dairy cows are based on maximizing available routes of heat exchange, convection, conduction, radiation, and evaporation. Areas in dairy operations in which cooling systems have been used to enhance cow comfort, improve milk production, reproductive efficiency, and profit include both housing and milking facilities. Currently, air movement (fans), wetting (soaking) the cow's body surface, high pressure mist (evaporation) to cool the air in the cows' environment, and facilities designed to minimize the transfer of solar radiation are used for heat abatement. Finally, improved understanding of photoperiod effects on cattle has allowed producers to maximize beneficial effects of photoperiod length while minimizing negative effects.

Major Advances in Disease Prevention in Dairy Cattle

This paper describes some of the major points of progress and challenges in health management of dairy cattle in the last 25 yr. A selection of the leading contributors in the field is acknowledged. Specific advances in the areas of transition cow management, epidemiology, udder health, applied immunology, housing design, calf health, and health-monitoring tools are described. The greatest advances in dairy health in the last 25 yr have been the shifts to disease prevention, rather than treatment, as well as from focus on individual animals to groups and herds. A fundamental advancement has been recognition of the multifactorial nature of almost all diseases of importance in dairy cattle. Epidemiology has been a critical new tool used to describe and quantify the interconnected risk factors that produce disease. Another major advance has been redefining disease more broadly, to include subclinical conditions (e.g., subclinical mastitis, ketosis, rumen acidosis, and endometritis). This expansion resulted both from improved technology to measure function at the organ level and, just as importantly, from the evolution of the health management paradigm in which any factor that limits animal or herd performance might be considered a component of disease. Links between cattle and people through consideration of environmental or ecosystem health are likely to further expand the concept of disease prevention in the future. Notable successes are decreases in the incidence of milk fever, clinical respiratory disease in adults, contagious mastitis, and clinical parasitism. There has also been improved protection through vaccination against coliform mastitis and bovine virus diarrhea. Since 1980, average herd size and milk production per cow have increased dramatically. Despite these increased demands on cows' metabolism and humans' management skills, the incidence of most common and important diseases has remained stable. Great progress has been made in understanding the biology of energy metabolism and immune function in transition dairy cows, the time at which the majority of disease occurs. Coupled with an emerging understanding of how best to provide for dairy cows' behavioral needs, transition cow management promises to be the foundation for progress in maintenance and enhancement of the health of dairy cows in the next 25 yr.

Major Technological Advances and Trends in Cheese

Over the last 25 yr, cheese production in the United States has more than doubled with most of the increase due to production in the western states. Processing large volumes of milk into cheese has necessitated changes in vat size and design, reliance on computer software, and milk standardization, including use of membrane concentration of milk either at the cheese plant or on the farm. There has been increased interest in specialty cheeses including cheese made from sheep, goat, and organic milks. In addition, membrane processing of whey into various value-added components has become routine. Changes in cheese manufacturing protocols have resulted in a reduction of the manufacturing time and the necessity for consistent and reliable starter activity. Major advances in the genetics of microorganisms have not only resulted in widespread use of fermentation-produced chymosin but also in starter bacteria with improved resistance to bacteriophage infection. Genomics and proteomics have increased the likelihood of the development of nonstarter adjuncts with specific enzymatic activity. Indeed, the use of adjunct microorganisms to produce cheese with a unique flavor profile or to produce cheese with more consistent or better quality flavor has gained almost universal acceptance.

Major Advances in Our Understanding of Nutritional Influences on Bovine Health

The Journal of Dairy Science has increasingly become a primary outlet for scientific research concerning the health of the dairy cow and her calf. This paper attempts to highlight Journal of Dairy Science articles that have linked nutrition and nutritional strategies to reduce disease incidence on the dairy farm. Disorders associated with an animal's inability to cope with the demands of high production include diseases such as milk fever and ketosis, which clearly are related to the cow's inability to maintain bodily functions in the face of negative calcium or energy balance. Improved nutrition of the late gestation cow can reduce the incidence of some of these disorders. Susceptibility to infectious disease is dependent on the integrity of the immune system, and recent studies have shed light on nutritional factors that affect leukocyte function. Other disorders, such as retained fetal membranes, udder edema, and displacement of the abomasum are not easily categorized as to their cause, but nutritional strategies have been developed to help prevent these disorders as well.

Major Advances in Extension Education Programs in Dairy Production

The dairy industry has seen structural changes in the last 25 yr that have an impact on extension programming. The number of cows in the United States has decreased by 17%, whereas the number of dairy farms has decreased by 74%. The average milk production per cow has increased from 5,394 to 8,599 kg/lactation. Even though there are fewer farms, dairy farm managers are asking for more specific and targeted information. The extension resources available have also decreased during this period. Because of these changes, shifts have taken place in extension programming and staffing. A key change has been a shift to subject matter-targeted programs and workshops. Extension has also incorporated and expanded use of the Internet. Discussion groups, subject matter courses, and searchable databases are examples of Internet use. There will be continuing shifts in the demographics of the US dairy industry that will influence future extension efforts. It is also probable that fewer extension professionals will be available to provide programming due to changes in funding sources at national, state, and local levels. Future shifts in extension programming will be needed to provide the information needs of the industry with a smaller number of extension workers.

Major Advances in Concentrated and Dry Milk Products, Cheese, and Milk Fat-Based Spreads

Advances in dairy foods and dairy foods processing since 1981 have influenced consumers and processors of dairy products. Consumer benefits include dairy products with enhanced nutrition and product functionality for specific applications. Processors convert raw milk to finished product with improved efficiencies and have developed processing technologies to improve traditional products and to introduce new products for expanding the dairy foods market. Membrane processing evolved from a laboratory technique to a major industrial process for milk and whey processing. Ultra-filtration and reverse osmosis have been used extensively in fractionation of milk and whey components. Advances in cheese manufacturing methods have included mechanization of the making process. Membrane processing has allowed uniform composition of the cheese milk and starter cultures have become more predictable. Cheese vats have become larger and enclosed as well as computer controlled. Researchers have learned to control many of the functional properties of cheese by understanding the role of fat and calcium distribution, as bound or unbound, in the cheese matrix. Processed cheese (cheese, foods, spreads, and products) maintain their importance in the industry as many product types can be produced to meet market needs and provide stable products for an extended shelf life. Cheese delivers concentrated nutrients of milk and bio-active peptides to consumers. The technologies for the production of concentrated and dried milk and whey products have not changed greatly in the last 25 yr. The size and efficiencies of the equipment have increased. Use of reverse osmosis in place of vacuum condensing has been proposed. Modifying the fatty acid composition of milkfat to alter the nutritional and functional properties of dairy spread has been a focus of research in the last 2 decades. Conjugated linoleic acid, which can be increased in milkfat by alteration of the cow's diet, has been reported to have anticancer, anti-atherogenic, antidiabetic, and antiobesity effects for human health. Separating milk fat into fractions has been accomplished to provide specific fractions to improve butter spreadability, modulate chocolate meltability, and provide texture for low-fat cheeses.

Major Advances in Applied Dairy Cattle Nutrition

Milk yield per cow continues to increase with a slower rate of increase in dry matter intake; thus, efficiency of ruminal fermentation and digestibility of the dietary components are key factors in improving the efficiency of feed use. Over the past 25 yr, at least 2,567 articles relating to ruminant or dairy nutrition have been published in the Journal of Dairy Science. These studies have provided important advancements in improving feed efficiency and animal health by improving quality of feeds, increasing feedstuff and overall diet digestibility, better defining interactions among feedstuffs in diets, identifying alternative feed ingredients, better defining nutrient requirements, and improving efficiency of ruminal fermentation. The publications are vital in continuing to make advancements in providing adequate nutrition to dairy cattle and for facilitating exchange of knowledge among scientists. Forages have been studied more extensively than any other type of feed. Cereal grains continue to be the primary contributors of starch to diets, and thus are very important in meeting the energy needs of dairy cattle. Processing of cereal grains has improved their use. Feeding by-products contributes valuable nutrients to diets and allows feedstuffs to be used that would otherwise be handled as wastes in landfills. Many of these by-products provide a considerable amount of protein, nonforage fiber, fat, and minerals (sometimes a detriment as in the case of P) to diets. The primary feeding system today is the total mixed ration, with still considerable use of the pasture system. Major improvements have occurred in the use of protein, carbohydrates, and fats in diets. Although advancements have been made in feeding practices to minimize the risk of metabolic diseases, the periparturient period continues to present some of the greatest challenges in animal health. Computers are a must today for diet formulation and evaluation, but fewer software programs are developed by universities. Several nutrition conferences are held regularly in the United States that are vital for transferring knowledge to the feed industry and the producers of food; the attendance at such programs has increased about 4-fold over the past 25 yr. More emphasis on animal welfare will direct some of the areas of nutrition research. Challenges ahead include having adequate funding for conducting applied nutrition research and for training of students as scientists and for employment in the feed industry.

Major Advances in Nutrition: Relevance to the Sustainability of the Dairy Industry

The typical cow has a maintenance requirement of about 10 Mcal of net energy for lactation (NEL) per day. Each kilogram of milk takes an additional 0.7 Mcal of NEL. Thus, the cow producing 45 kg of milk per day needs 4 times as much total energy as she needs for her maintenance requirement alone. The elite cow producing 90 kg/d needs 7 times as much total energy as she needs for maintenance alone. Consequently, the efficiency of using feed energy is much greater for the elite cow than it was for the cow of 100 yr ago consuming a diet of mostly forage. With increased productivity has come the need for fewer cows to produce milk on a per capita basis and increases in net income per cow. However, compared with energetic efficiency, the efficiency of using feed protein to make milk protein has not increased as dramatically, partly because cows are often fed protein in excess. This nitrogen waste is an environmental concern; N losses in manure contribute to water pollution and ammonia emissions from dairy farms. However, the complexities of protein nutrition and limitations in measuring feed N fractions make accurate specifications for feed protein fractions difficult. The economic risk of underfeeding protein is greater than the risk of overfeeding protein, so protein efficiency has not been maximized in the past, nor is it likely to be maximized in the near future. Most cows also are fed excess P, a notable contaminant of surface waters, but several recent studies have shown that feeding P above NRC recommendations has no utility for milk production or fertility. The goal of this article is to examine the impact of nutrition on productivity, efficiency, environmental sustainability, and profitability of the dairy industry.

Major Advances in Testing of Dairy Products: Milk Component and Dairy Product Attribute Testing

Milk component analysis is relatively unusual in the field of quantitative analytical chemistry because an analytical test result determines the allocation of very large amounts of money between buyers and sellers of milk. Therefore, there is high incentive to develop and refine these methods to achieve a level of analytical performance rarely demanded of most methods or laboratory staff working in analytical chemistry. In the last 25 yr, well-defined statistical methods to characterize and validate analytical method performance combined with significant improvements in both the chemical and instrumental methods have allowed achievement of improved analytical performance for payment testing. A shift from marketing commodity dairy products to the development, manufacture, and marketing of value added dairy foods for specific market segments has created a need for instrumental and sensory approaches and quantitative data to support product development and marketing. Bringing together sensory data from quantitative descriptive analysis and analytical data from gas chromatography olfactometry for identification of odor-active compounds in complex natural dairy foods has enabled the sensory scientist and analytical chemist to work together to improve the consistency and quality of dairy food flavors.

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.

The Holstein cow in embryo transfer today as compared to 20 years ago

Embryo transfer practice and results were examined over a 20-year period in Holstein cows and heifers within four commercial embryo transfer programs located in different areas of North America. Mean embryo production per collection decreased (P < 0.05) in one program over time, but not in the other three. Changes in the type of cows entering embryo transfer programs, the number of times they were superstimulated and changes in the brands of gonadotropins used for superstimulation all complicated the analysis of embryo production over time. Data reveal higher pregnancy rates (P < 0.001) following transfer of embryos into Holstein heifers than into lactating dairy cows. It is not clear whether pregnancy rates have decreased over time as a result of the change from surgical to non-surgical embryo transfer. In the two programs in which pregnancy rates were analyzed, there was a decrease (P < 0.001) when non-surgical transfers were adopted in one program, while no change occurred in the other. One of the biggest changes in all programs was that more than 50% of embryos recovered from donors are now frozen after collection, whereas the majority were transferred fresh 20 years ago.

Breeding dairy cows for the future in New Zealand

A brief history of the breeding of dairy cattle in New Zealand is provided. Dairy farming in New Zealand is unique compared with the majority of dairy systems in the developed world. New Zealand has a dependence on grass-based diets and a strict requirement for a 365-day calving interval. Four main areas are discussed: future traits to evaluate, advances in genetic evaluation technologies, impacts of crossbreeding, and future progeny testing schemes. These areas are not independent, e.g. the trend of increasing numbers of crossbred cattle in the national herd will have major impacts on the design of breeding schemes. It is foreseeable that in the future there will be improvements in the national breeding goal to better reflect on-farm profitability, and in the definition of traits and methods of data capture within the national breeding goal. Methods of selection and genetic evaluation that are currently feasible for a small population will become feasible for large populations as computing power improves. Genetic improvement of cows in New Zealand will continue to be a critical component of the increased economic efficiency achieved on dairy farms in this country.

Inbreeding in Danish dairy cattle breeds

The purpose of this study was to monitor current and predict future rates of inbreeding in the Danish dairy breeds. Calves born from 1999 until 2003 and registered as Danish Holstein (1,883,983), Danish Jersey (336,966), or Danish Red (261,047) were reference populations. Average complete generation equivalent was approximately 7. For calves born in 2003, average inbreeding was 3.9, 3.4, and 1.4% for Holstein, Jersey, and Danish Red, respectively. In recent years, effective population sizes were 49, 53, and 47, respectively. Based on coancestry statistics, future effective population sizes will be 43, 42, and 51, respectively. The effective number of founders, effective number of ancestors, and effective number of founder genomes were calculated. These measures of genetic diversity were all low for Holstein and Jersey and somewhat larger for Danish Red. The most important ancestors of Danish Holstein were Elevation (13.8%), Chief (10.9%), and Bell (8.5%). The most important ancestor of Danish Red was Momentum (9.4%), a Red Holstein-Friesian. The most important ancestor for Danish Jersey was FYN Lemvig (12.1%) with a large number of progeny in the reference population. The results of this study indicate the necessity for active management of the rate of inbreeding in the future.

An economic evaluation of recombinant bovine somatotropin approval in Japan

A comprehensive econometric model was developed to evaluate potential impacts of recombinant bovine somatotropin (rbST) approval in Japan. Three novel features of the analyses include 1) investigation of impact of rbST on herd-size structure, 2) determination of economic feasibilities of rbST adoption by herd size, and 3) evaluation of policies to mitigate negative effects of rbST approval. Simulation analysis was conducted over a 10-yr projected period assuming rbST was approved in Japan in 2001. Nine hypothetical scenarios were simulated to examine sensitivity of simulation results. Simulation results indicate that rbST approval would accelerate structural change in Japan's dairy industry toward fewer, larger farms. Negative effects of rbST on farm income are projected to be more severe for smaller farms, because of higher costs, lower profit-earning ability, lower milk yields, and lower adoption rates of rbST. Larger farms benefit from rbST adoption if milk demand is maintained. However, if concerns about rbST induce significant milk demand decreases, even the largest farms' income and cow numbers will decrease. Thus, Japan's dairy industry could be caught in a double downward spiral of declining milk prices and production. Assuming rbST is approved, small farms would benefit by using the technology, but they fare best if rbST is not approved. Two policies could be effective in mitigating possible farm income losses. First, lost farm income can be offset if dairy cooperatives can exercise greater market power to control fluid milk marketings. Second, because generic milk advertising has positive effects on both milk demand and farm income, increasing check-off rates to fund more advertising could ease farm income losses.

[Total bacterial count in raw milk from the dairy farms that characterize the zone northwest of Santa Fe and south of Santiago del Estero]

A total of 6,998 raw milk samples of bulk tank, belonging to 55 dairy farms associated to the Cooperativa Tambera Nueva Alpina Ltda., were collected between the years 1993 and 2002. The Total Mesophilic Aerobic Microorganisms Count was analyzed, obtaining a medium value of 1.2 x 10(5) +/- 2.4 x 10(5) CFU/ml that characterizes the zone. The final year of experience, observed a 97% of dairy farms evaluated with averages < or = 1.0 x 10(5) CFU/ml. Only a 3% it surpasses this limit, not being found establishments with levels over 1.5 x 10(5) CFU/ml. Relating this indicators with compositionals parameters, the most significant correlation resulted for: Total Bacterial Count vs Acidity (r = 0.292; P < 0.001) and Total Bacterial Count vs Freezing Point (r = 0.157; P < 0.001. The microbiological quality in raw milk of dairy farms belonging to the northwest zone of Santa Fe and south of Santiago del Estero showed a significant improvement during this time.

The current status and future of commercial embryo transfer in cattle

A commercially viable cattle embryo transfer (ET) industry was established in North America during the early 1970s, approximately 80 years after the first successful embryo transfer was reported in a mammal. Initially, techniques for recovering and transferring cattle embryos were exclusively surgical. However, by the late 1970s, most embryos were recovered and transferred nonsurgically. Successful cryopreservation of embryos was widespread by the early 1980s, followed by the introduction of embryo splitting, in vitro procedures, direct transfer of frozen embryos and sexing of embryos. The wide spread adoption of ethylene glycol as a cryoprotectant has simplified the thaw-transfer procedures for frozen embryos. The number of embryos recovered annually has not grown appreciably over the last 10 years in North America and Europe; however, there has been significant growth of commercial ET in South America. Within North America, ET activity has been relatively constant in Holstein cattle, whereas there has been a large ET increase in the Angus breed and a concomitant ET decrease in some other beef breeds. Although a number of new technologies have been adopted within the ET industry in the last decade, the basic procedure of superovulation of donor cattle has undergone little improvement over the last 20 years. The export-import of frozen cattle embryos has become a well-established industry, governed by specific health regulations. The international movement of embryos is subject to sudden and dramatic disturbances, as exemplified by the 2001 outbreak of foot and mouth disease in Great Britain. It is probable that there will be an increased influence of animal rights issues on the ET industry in the future. Several companies in North America are currently commercially producing cloned cattle. The sexing of bovine semen with the use of flow cytometry is extremely accurate and moderate pregnancy rates in heifers have been achieved in field trials, but sexed semen currently is available in only a few countries and on an extremely limited basis. As of yet, all programs involving the production of transgenic cattle are experimental in nature.

Dairy processing

The United States dairy processing sector is dynamic and adaptive to new changes in the market place. Changes in consumer preferences and manufacturing technologies are resulting in new challenges to the processing sector. Consumers want a wider array of quality dairy products. Fluid processors are adapting to changing consumer demands for beverage products by introducing new flavors, providing ultrapasteurization, and using creative packaging. In addition, United States food manufacturers are requesting dairy processors to provide new dairy fractions such as MPC for new nutrition products. United States dairy policy is attempting to adapt to these changes. Federal order reform has resulted in new market-oriented signals for dairy farmers to produce what the market wants; namely, quality milk components. US dairy farmers, however, also wants to maintain programs such as the DPSP that have had the unfortunate consequence of spurring demand for protein imports (i.e., MPCs, casein, and caseinates) and also resulted in a disincentive to produce these new innovative protein products here in the United States. Surplus skim milk solids are now moving into US Government warehouses rather than into commercial markets. The future of the United States dairy industry will clearly be toward producing innovative products that the market wants. There is a strong market for dairy products not only here in the United States but also overseas, which will mean learning to compete on a global scale. The challenge is to modernize our United States milk pricing programs to provide dairy farmers and processors proper price signals while providing a minimum level of support to dairy farmers. The benefit of a greater orientation toward the market place will be stronger rates of growth for United States-produced dairy products.

Changes in working conditions and health among dairy farmers in southern Sweden. A 14-year follow-up

The objective of this study was to describe and analyse the changes in working conditions and health among dairy farmers in Scania in southern Sweden during the period 1988-2002 by a repeat of a mail-in survey. Altogether, 83 % of the male and 90 % of the female dairy farmers reported some kind of symptoms in the musculoskeletal system during the 12 months prior to the 2002 questionnaire. This is an increase compared to the farmers in 1988. The highest significant changes were an increase of symptoms in the shoulder, neck and in the wrists/hands. The milkers reported most often incidental as well as persistent symptoms in the shoulders. The frequency of hip symptoms was significantly higher among those male milkers who had quit milking during the interim than for the active milkers in 1988. The milkers studied in 2002 had, on average, increased their working time per week, increased the number of cows milked as well as the use of more milking units. In 1988, almost all the milkers studied were working in tethering systems while in 2002 more than one quarter were working in loose-housing systems. The opinion among most of the farmers, both in 1988 and in 2002, regardless of age or sex, was that silage handling and the milking procedure were the most strenuous work operations. On the other hand, the milkers obtained their greatest pleasure from the actual milking job as well as from their work to promote the welfare of the animals. Unprofitability and great investment demands had a bearing on the retirement of milkers but, on the other hand, a high potential of the milkers could have continued 10-15 more years as dairy farmers if the work conditions had been better, e.g. associated with fewer health problems. Apart from the need for developing technical devices to facilitate the milking operation, further research is needed concerning the dairy farmers' well-being and quality of life, perceived stress, and leisure time activities and how these and similar factors influence the prevalence of musculoskeletal symptoms. Strategies for preventive and intervention measures must consider physical workplace factors as well as personal and lifestyle characteristics.

Milk and dairy products in the 21st century. Prepared for the 50th anniversary of the journal of agricultural and food chemistry

Dairying into the 21st century will largely continue with the trends seen in the past few decades, although there is always the possibility of an unlikely but disruptive event. The politics of globalization will potentially be important in freeing up global trade in dairy products. Production on the farm will become increasingly efficient, resulting in continuing price benefits to the consumer. At the same time, increasing attention will be paid by the consumer, producer, and manufacturer to safety and quality issues. Environmental concerns will increase in importance, and the issue of methane production may be important for the industry over the next two decades. It is unlikely that genetically modified milk will be introduced soon, even if public acceptance ceases to be an issue; however, the use of genetic markers for accelerated genetic improvement of cows will have rapidly increasing importance. Despite increasing pressure from nonmilk alternatives, milk and dairy will still be the best sources of nutrition for the young and for traditional dairy products. Consumer concerns will be of overriding importance for the industry, and the safety of dairy foods must become absolute. Recent advances in the chemical, physical, and information sciences and technologies will be utilized to gain greater understanding of the increasingly complex food systems and to support the consumer objectives.

Is the modern high potential dairy cow suitable for organic farming conditions?

It is not acceptable to compromise animal welfare in any system of farming. Feeding should be aimed at meeting the nutritional requirements at the various stages of production. This paper deals with the detrimental effects that organic, extensive or low input farming systems may have on the energy status in early lactation of the high potential dairy cow. Bovine ketosis is the most important disease resulting from insufficient energy intake in early lactation. It is also important to realize that ketosis is a part of the so-called periparturient disease complex, which includes milk fever, mastitis, retained placenta, endometritis and poor fertility also. All these diseases are interrelated and reflect to a large extent the nutritional status of the animal. If organic dairy farming is to be successful the breeding programmes have to divert from selection for high yields as a main goal, to more emphasis on a flatter lactation curve, less production diseases and longevity.

Monitoring nitrogen leaching for the evaluation of the Dutch minerals policy for agriculture in clay regions

This paper presents the results of the Dutch monitoring program for agriculture in the clay regions for the period 1996-2000 and evaluates the monitoring strategy. A wide range of farms (25 to 85%) had a NO3--N concentration in tile drainwater higher than the EU standard of 11.3 mg/l. The low figure is related to wet winters; the high, to dry winters. Arable farms are more prone to NO3- leaching than dairy farms. On arable farms, about 25% of the N surplus leached to groundwater and tile drainwater, on dairy farms this was about 15%. N in tile drainwater has shown to be the best indicator for monitoring the effects of farming practice changes in the clay regions. The average NO3--N concentration in tile drainwater was 18.8 and 3.2 mg/l in borehole water on farms where both were monitored. It is known that N use has a relationship with NO3- in tile drainwater and not with NH4+ and organic N. The presented results indicate that crop rotation and precipitation strongly influence NO3- concentration in tile drainwater.