Public and farmer perceptions of dairy cattle welfare in the United States.

This research used surveys of the public and dairy farmers in the United States to assess perceptions and attitudes related to dairy cattle welfare. Sixty-three percent of public respondents indicated that they were concerned about dairy cattle welfare. Most public respondents agreed that animal welfare was more important than low milk prices but that the average American did not necessarily agree. Most public respondents had not viewed media stories related to dairy cattle welfare. Respondents who had viewed these stories did so on television or Internet. The United States Department of Agriculture (USDA) was viewed as the most accurate source of information related to dairy cattle welfare, followed by the Humane Society of the United States (HSUS) and the American Veterinary Medicine Association (AVMA). Both public and dairy farmer respondents viewed farmers as having the most influence on dairy cattle welfare. However, there was a general pattern of public respondents indicating that groups including USDA, HSUS, and AVMA had a relatively larger influence on dairy cattle welfare than did farmer respondents. In contrast, dairy farmers indicated that individual actors-farmers, veterinarians, consumers-had more influence than the public indicated. When asked about production practices, most public respondents indicated that they would vote for a ban on antibiotic use outside of disease treatment or for the mandated use of pain control in castration. However, a minority indicated they would vote to ban the use of recombinant bovine somatotropin (rbST) or to pay a premium for milk produced without rbST. With respect to explaining public support for the production practice bans and limits, respondents were more likely to vote for the restrictions if they were older, female, had higher income, or had viewed animal welfare stories in the media.

The Coalition for Sustainable Egg Supply: A unique public-private partnership for conducting research on the sustainability of animal housing systems using a multistakeholder approach.

The growing emphasis on ensuring the sustainability of animal agriculture is providing an impetus for the adoption of new approaches to structuring and conducting research. Sustainability is a complex topic involving many considerations related to the economic, social, and environmental impacts of production systems. Successfully addressing this topic requires multidisciplinary research as well as a high degree of communication with food system stakeholders to ensure that the research results contribute to informed decision making. In this paper, we provide an overview of a public-private partnership, the Coalition for Sustainable Egg Supply (CSES), which was formed to support research evaluating the sustainability of laying hen housing systems. Because of increasing public concerns about the behavioral restriction imposed on laying hens housed in conventional cages, the U.S. egg industry is faced with a need to transition to alternative systems. However, before the CSES project, there was limited information available about how this transition might affect trade-offs related to the sustainability of egg production. The goal of the CSES project was to provide this information by conducting holistic research on a commercial farm that had 3 different hen housing systems. The CSES members represented a variety of stakeholders, including food retailers and distributors, egg producers, universities, and governmental (USDA ARS) and nongovernmental organizations. The CSES was facilitated by a not-for-profit intermediary, the Center for Food Integrity, which was also responsible for communicating the research results to food system stakeholders, including via quantitative and qualitative consumer research. In this paper, we describe the structural aspects of the CSES that were responsible for the successful completion and dissemination of the research as well as the insights that were gained regarding multidisciplinary and multi-institutional collaboration, conducting commercial-scale research, fostering and maintaining stakeholder interaction, and communicating research results. Although not without limitations, this project demonstrates that public-private partnerships can be effective strategies for addressing sustainability questions related to animal agriculture and, thus, serves as a useful model for the other animal industries.

Perch use by laying hens in a commercial aviary.

Non-cage housing systems, such as the aviary, are being implemented by the laying hen industry, including in North America, in an attempt to improve the welfare of hens. Perches are a resource that is consistently included in aviaries. Hens are strongly motivated to perch, and perching can improve leg bone strength. However, hens may prefer elevated perches, particularly at night, and thus simply providing perches is not enough to improve welfare; they must be provided in a way that allows all hens to access them. Observations of laying hens using perches and ledges (flat, solid metal shelves to assist hens' movement between tiers) in a commercial aviary revealed variation in where hens roosted within the tiered aviary enclosure across the flock cycle (peak, mid and end of lay; P < 0.001 for all age points). Hens most often preferred roosting in the highest enclosure levels, leading to crowding on upper perches and ledges while perch space remained available on lower levels. Restricted access to preferable perches may cause frustration in hens, leading to welfare issues. Hens roosted more on perches at peak lay than mid and end lay (P < 0.001) but roosted less on ledges at peak lay than mid and end lay (P < 0.001). Additionally, more hens roosted on both perches and ledges in the 'dark' observation period compared with the number of hens roosting during the 'light' observation period (P < 0.001). Further research should look at all structural elements within the system that are used by hens for roosting, such as edges of tiers and upper wire floors, to evaluate how changes in perching preferences across the lay cycle may correlate with system design and bird-based parameters.

Litter use by laying hens in a commercial aviary: dust bathing and piling.

The laying hen industry, including in the United States, is responding to social concerns about hen welfare by implementing alternative housing systems such as the aviary, to provide more space and resources to large groups of hens. Data detailing the behavior of hens in commercial aviaries is needed to determine hens' use of the resources in order to understand their impact on hen welfare. The open litter area of aviaries provides additional space for hens during the day. Litter is also a substrate for dust bathing which is a strongly motivated natural behavior. Hens are often synchronous in their performance of dust bathing, which may lead to overcrowding in the litter area. Additionally, the open litter area can facilitate expression of unusual behavior such as flock piling (defined as the occurrence of densely grouped clusters of hens, resulting from no obvious cause and occurring randomly throughout the day and flock cycle) which may be a welfare concern. Therefore, we conducted observations of hen occupancy of the open litter area and the performance of dust bathing and flock piling across 3 production points (peak lay, mid lay and end of lay) for two flocks of Lohmann White laying hens housed in a commercial aviary. All areas of the open litter area were occupied to the same degree. Hens performed dust bathing throughout the day but showed peak dust bathing activity in the afternoon for Flock 1 (all P < 0.001) and in the late morning for Flock 2 (all P < 0.001). Overall, 174 incidents of piling behavior were observed between the 2 flocks, with piles varying in size, duration, and time of occurrence; however, no smothering was detected. Crowding on the open litter area sometimes occurred during peak periods of synchronous dust bathing and when hens piled. Further research is needed to understand the welfare implications of individual hen use of the open litter area and the causes and welfare implications of hen piling.

Laying hen movement in a commercial aviary: Enclosure to floor and back again.

Many producers in the laying hen industry, including in North America, are phasing out conventional cages in response to consumer demands and sometimes subsequent legislation. Alternative housing systems such as aviaries are being implemented in an attempt to improve hen welfare. Aviaries provide additional space and resources to groups of hens, including a litter area on the floor. However, little is known about hen movement between tiered enclosures and floor litter areas in aviary systems. Diurnal rhythms and social attraction may result in peak times of movement that could lead to overcrowding of areas, or alternatively hen preferences may lead to some areas not being fully utilized. We monitored hen movement between tiered enclosures and litter areas, including movement on and off the outer perch, across the day at peak, mid and end of lay in a commercial aviary. Hens moved onto and off of the open litter area across the day, transitioning between tiered enclosures, outer perches, open litter areas, and litter areas under tiered enclosures. At certain times of day, there were periods of greater hen movement down to the open litter area and between litter areas. For example, more hens were typically observed exiting enclosures, jumping from perches to open litter, and traveling between open litter and litter under tiered enclosures in the morning (all P ≤ 0.001). In all but one instance, more hens were observed on open litter areas in the afternoon than at other times of day (all P ≤ 0.029). However, hen re-entry to tiered enclosures showed less circadian patterning. Hen movement was observed between areas of interest at all sampled time periods, indicating hens use all areas of the system. Further research should examine whether all individual hens do move between areas equally, including within levels of the tiered enclosure, or if crowding occurs on the outer perches or in the litter during times of peak movement.

Failed landings after laying hen flight in a commercial aviary over two flock cycles.

Many egg producers are adopting alternative housing systems such as aviaries that provide hens a tiered cage and a litter-covered open floor area. This larger, more complex environment permits expression of behaviors not seen in space-limited cages, such as flight. Flight is an exercise important for strengthening bones; but domestic hens might display imperfect flight landings due to poor flight control. To assess the potential implications of open space, we evaluated the landing success of Lohmann white laying hens in a commercial aviary. Video recordings of hens were taken from 4 aviary sections at peak lay, mid lay and end lay across two flock cycles. Observations were made in each focal section of all flights throughout the day noting flight origin and landing location (outer perch or litter) and landing success or failure. In Flock 1, 9.1% of all flights failed and 21% failed in Flock 2. The number of flights decreased across the laying cycle for both flocks. Proportionally more failed landings were observed in the double row sections in Flock 2. Collisions with other hens were more common than slipping on the ground or colliding with aviary structures across sections and flocks. More hens slipped on the ground and collided with physical structures at peak lay for Flock 2 than at other time points. More collisions with other hens were seen at mid and end lay than at peak lay for Flock 2. Landings ending on perches failed more often than landings on litter. These results indicate potential for flight-related hen injuries in aviary systems resulting from failed landings, which may have implications for hen welfare and optimal system design and management.

Improvement of turkey breast meat quality and cooked gel functionality using hot-boning, quarter sectioning, crust-freeze-air-chilling and cold-batter-mincing technologies.

The effect of rapid carcass chilling on breast meat quality was evaluated using commercial (COMM) and random-bred (RB) turkeys. Immediately after slaughter, 48 turkeys from COMM or RB line were randomly subjected to one of four chilling methods: 1) water-immersion chilling (WIC) of the carcasses at 0°C ice slurry, 2) WIC after temperature abuse (TA) of the carcasses at 40°C for 30 min (TA-WIC), 3) hot-boning, quarter sectioning, and crust-freeze-air-chilling (HB-(1)/4CFAC) of breast fillets at -12°C, and 4) HB-(1)/4CFAC of fillets after TA of carcasses (TA-HB-(1)/4CFAC). The TA increased carcass and fillet temperatures by ∼1.3 and ∼4.1°C, respectively, regardless of turkey line, whereas HB-(1)/4CFAC of fillets required 28 and 33% of carcass chilling time for COMM and RB, respectively. During chilling, COMM breast pH rapidly reduced from 6.04 to 5.82, resulting in a significantly lower pH than RB after chilling (P < 0.05), whereas COMM R-value sharply increased from 1.17 to 1.43, causing no difference from RB (P > 0.05). Significantly higher L* value and cooking yield (P < 0.05) were seen in the samples of TA and WIC than those of no TA and HB-(1)/4CFAC, respectively, with no difference observed between COMM and RB fillets (P > 0.05). Higher values of hardness, gumminess, and chewiness were found for RB, no TA, and HB-(1)/4CFAC gels than COMM, TA, and WIC, respectively. These results generally indicated that protein quality and textural properties of turkey fillets were improved, regardless of strains or temperature abuse, using HB-(1)/4CFAC technology.

Fear responses and postmortem muscle characteristics of turkeys of two genetic lines.

Commercial turkey production has increased greatly in recent decades. Along with increased production, problems with turkey meat quality have also increased. Research with other species has demonstrated that differences in meat quality exist among pigs and cattle differing in characteristics such as fearfulness. However, associations between fear responses and postmortem (PM) muscle characteristics related to the meat quality of turkeys have not been examined. This study evaluated the test-retest repeatability of responses of male commercial (COMM) and randombred (RB) turkeys in an open field (OF) test, which is used to assess fear and activity levels of poultry. Another objective of this study was to evaluate the relationship between behavioral OF responses and PM breast muscle characteristics (pH and R-value) that are related to meat quality. Thirdly, this study evaluated differences in pH and R-value between the turkey lines. Male COMM and RB turkeys were each housed in groups in 4 pens. Turkeys were individually tested in an OF (2.74×2.74 m, divided into 81 squares) at 1, 4, and 11 wk (COMM N=27; RB N=33). Turkeys were then grouped into clusters based on a cluster analysis of OF behavior. Turkeys were processed and meat quality characteristics were evaluated at 15-17 wk for COMM and 20-21 wk for RB turkeys. Results were analyzed using a mixed model (SAS 9.4). Breast muscle pH and R-value did not differ between genetic lines, and there were no differences in pH and R-value among clusters within genetic lines. These findings suggest that OF responses measured during rearing are not related to PM breast muscle pH and R-value, which ultimately affect meat quality. Further research is needed to assess whether other types of fear responses are associated with meat quality and whether differences in R-value between genetic lines are associated with differences in other meat quality characteristics.

The Coalition for Sustainable Egg Supply project: An introduction.

In the United States, empirical information on the sustainability of commercial-scale egg production is lacking. The passage of state regulations specific to hen housing created urgency to better understand the effects of different housing systems on the sustainability of the egg supply, and stimulated the formation of a coalition, the Coalition for a Sustainable Egg Supply (CSES), to conduct research on this topic. The CSES is a multi-stakeholder group with 27 members, including food manufacturers, research institutions, scientists, restaurants, food service, retail food companies, egg suppliers, and nongovernmental organizations. A commercial-scale study was developed to better understand the effect of 3 housing systems (conventional cage, enriched colony, and cage-free aviary) on 5 areas related to a sustainable egg supply. These 5 sustainability areas represent effects on people, animals, and the environment: animal health and well-being, environment, food safety, worker health and safety, and food affordability. Five teams of scientists, each associated with a sustainability area, conducted an integrated field study at a commercial site in the upper Midwest through 2 flock cycles in 3 housing systems. This paper provides a brief overview of the CSES project to serve as an introduction for the papers that follow in this volume of Poultry Science.

Comparative evaluation of three egg production systems: Housing characteristics and management practices.

This paper is an integral part of the special publication series that arose from the multidisciplinary and multi-institutional project of the Coalition for Sustainable Egg Supply (CSES). The CSES project involves 3 housing systems for egg production at the same research farm site in the Midwest, USA, namely, a conventional cage (CC) house, an aviary (AV) house, and an enriched colony (EC) house. The CC house (141.4 m L×26.6 m W×6.1 m H) had a nominal capacity of 200,000 hens (6 hens in a cage at a stocking density of 516 cm2/hen), and the cages were arranged in 10 rows, 8 tiers per cage row, with a perforated aisle walkway at 4-tier height. The AV house (154.2 m L×21.3 m W×3.0 m H) and the EC house (154.2 m L×13.7 m W×4.0 m H) each had a nominal capacity of 50,000 hens. The AV house had 6 rows of aviary colonies, and the EC house had 5 rows of 4-tier enriched colonies containing perches, nestbox, and scratch pads (60 hens per colony at a stocking density of 752 cm2/hen). The overarching goal of the CSES project, as stated in the opening article of this series, was to comprehensively evaluate the 3 egg production systems from the standpoints of animal behavior and well-being, environmental impact, egg safety and quality, food affordability, and worker health. So that all the area-specific papers would not have to repeat a detailed description of the production systems and the management practices, this paper is written to provide such a description and to be used as a common reference for the companion papers.

Integration: valuing stakeholder input in setting priorities for socially sustainable egg production.

Setting directions and goals for animal production systems requires the integration of information achieved through internal and external processes. The importance of stakeholder input in setting goals for sustainable animal production systems should not be overlooked by the agricultural animal industries. Stakeholders play an integral role in setting the course for many aspects of animal production, from influencing consumer preferences to setting public policy. The Socially Sustainable Egg Production Project (SSEP) involved the development of white papers on various aspects of egg production, followed by a stakeholder workshop to help frame the issues for the future of sustainable egg production. Representatives from the environmental, food safety, food retail, consumer, animal welfare, and the general farm and egg production sectors participated with members of the SSEP coordination team in a 1.5-d workshop to explore socially sustainable egg production. This paper reviews the published literature on values integration methodologies and the lessons learned from animal welfare assessment models. The integration method used for the SSEP stakeholder workshop and its outcome are then summarized. The method used for the SSEP stakeholder workshop can be used to obtain stakeholder input on sustainable production in other farm animal industries.

Animal behavior and well-being symposium: Farm animal welfare assurance: science and application.

Public and consumer pressure for assurances that farm animals are raised humanely has led to a range of private and public animal welfare standards, and for methods to assess compliance with these standards. The standards usually claim to be science based, but even though researchers have developed measures of animal welfare and have tested the effects of housing and management variables on welfare within controlled laboratory settings, there are challenges in extending this research to develop on-site animal welfare standards. The standards need to be validated against a definition of welfare that has broad support and which is amenable to scientific investigation. Ensuring that such standards acknowledge scientific uncertainty is also challenging, and balanced input from all scientific disciplines dealing with animal welfare is needed. Agencies providing animal welfare audit services need to integrate these scientific standards and legal requirements into successful programs that effectively measure and objectively report compliance. On-farm assessment of animal welfare requires a combination of animal-based measures to assess the actual state of welfare and resource-based measures to identify risk factors. We illustrate this by referring to a method of assessing welfare in broiler flocks. Compliance with animal welfare standards requires buy-in from all stakeholders, and this will be best achieved by a process of inclusion in the development of pragmatic assessment methods and the development of audit programs verifying the conditions and continuous improvement of farm animal welfare.

Introduction--the Socially Sustainable Egg Production project.

The social and political pressure to change egg production from conventional cage systems to alternative systems has been largely driven by the desire to provide more behavioral freedom for egg-laying hens. However, a change of this magnitude can affect other components of the production system and may result in unintended outcomes. To understand this issue, a Socially Sustainable Egg Production project was formed to 1) conduct a holistic and integrated systematic review of the current state of knowledge about various aspects of sustainable egg production, and 2) develop a coordinated grant proposal for future extramural funding based on the research priorities identified from the review. Expert study groups were formed to write evidence-based papers in 5 critical sustainability areas: hen health and welfare, economics, food safety and quality, public attitudes, and environmental impacts. These papers were presented as the PSA Emerging Issues Symposium on Social Sustainability of Egg Production at the 2010 Poultry Science Association meeting.

Anterior mitral leaflet curvature in the beating ovine heart: a case study using videofluoroscopic markers and subdivision surfaces.

The implantation of annuloplasty rings is a common surgical treatment targeted to re-establish mitral valve competence in patients with mitral regurgitation. It is hypothesized that annuloplasty ring implantation influences leaflet curvature, which in turn may considerably impair repair durability. This research is driven by the vision to design repair devices that optimize leaflet curvature to reduce valvular stress. In pursuit of this goal, the objective of this manuscript is to quantify leaflet curvature in ovine models with and without annuloplasty ring using in vivo animal data from videofluoroscopic marker analysis. We represent the surface of the anterior mitral leaflet based on 23 radiopaque markers using subdivision surfaces techniques. Quartic box-spline functions are applied to determine leaflet curvature on overlapping subdivision patches. We illustrate the virtual reconstruction of the leaflet surface for both interpolating and approximating algorithms. Different scalar-valued metrics are introduced to quantify leaflet curvature in the beating heart using the approximating subdivision scheme. To explore the impact of annuloplasty ring implantation, we analyze ring-induced curvature changes at characteristic instances throughout the cardiac cycle. The presented results demonstrate that the fully automated subdivision surface procedure can successfully reconstruct a smooth representation of the anterior mitral valve from a limited number of markers at a high temporal resolution of approximately 60 frames per minute.

The ethical aspects of regulating production.

Polls and surveys conducted within the United States show general agreement that there is public support for the protection of farm livestock and poultry. Concurrent with the growing public sentiment is the recent adoption of socially responsible corporate policies by major food retailers relative to animal welfare. The animal welfare assurance and audit programs developed by the private sector are an attempt to assure consumers that best practice measures and independent oversight result in a reasonable quality of life for food-producing animals. These programs represent voluntary self-regulation and arguably a market-based approach to secure the welfare of food-producing animals. Animal advocacy organizations historically seek regulatory oversight of animal care practice. Legislative routes that require government promulgation and enforcement of animal care regulations represent an involuntary form of animal welfare assurance. There are ethical considerations concerning the employment of voluntary or involuntary regulation of the welfare of food-producing animals. For example, degree of public endangerment, economic impact, viability of small to medium producers, food price, food quality, and food security are prominent among the ethical considerations in deliberating whether to impose regulatory mandates on production. In either regulatory approach, the public must be convinced that the welfare of food-producing animals can be secured in a transparent and convincing manner.

Value-added animal agriculture: inclusion of race and gender in the professional formula.

The Morrill Act establishing the land grant university system created public higher education institutions and paved the way for women and racial minorities to access them. Today women are -50% of the undergraduate population in animal science (AS) departments at the original land grant state universities, but racial minorities lag far behind, in part because the schools created under the 1890 legislation provided a diversion away from the state universities. Demographic trends from the U.S. Census and the Bureau of Labor Statistics indicate increasing positive growth in nonwhite workforce participation, with concurrent decreases in non-Hispanic male participation; men and women will be nearly equally represented by early in the 21st Century. In the faculties of AS departments, both women and minorities are seriously under-represented; causative factors underlying this phenomenon are similar. Although, historically, adherence to role stereotypes and divisions of labor explain some of the under-representation, these assumptions do not hold across all economic classes. Other factors contributing to the scarcity of women and faculty of color in AS include assumptions and mechanisms of scientific research itself; the very neutrality and disinterestedness of researchers, inherent in the scientific method, prevent recognition that values and personal biases affect decisions of hiring selections and mentoring effectiveness. We explore the cultural factors that underlie these values and biases that are common not only to agriculture but also to science more broadly.

What are animal science departments doing to address contemporary issues?

Animal science departments are principle progenitors and disseminators of scientific information relating to the production of agricultural animals and their food products. The Land-Grant university missions of teaching, research, and extension are conduits designed to advance and enhance scientific knowledge within agriculture and to make this knowledge available to the public. I conducted an electronic survey to determine whether animal science departments are addressing contemporary issues through the traditional missions of the Land-Grant university system, which issues they are addressing, and how they are addressing these issues. Sixty-three animal science department administrative heads (AH) were contacted through an E-mail listserve maintained through Michigan State University. An introductory letter described the goals of the survey and asked the AH to submit contact information for faculty coordinators of teaching, research, and extension within their departments. Forty-nine percent of the administrative heads responded and submitted contact information for 72 faculty members. Survey questions were sent to the identified faculty. The total survey return was 38.9%, 37.7% of the respondents answered questions for teaching, 31.1% for research, and 31.1% for extension. Animal waste, animal welfare, and food safety are examples of issues where all three missions have concentrated efforts. However, graduate student education on issues was identified as lacking emphasis. Animal science departments are responding to contemporary issues in all three of the Land-Grant mission components.

Farm animal well-being and intensive production systems.

Animal welfare, or well-being, is a social issue with ethical, scientific, political, and aesthetic properties. Answering questions about the welfare of animals requires scientific definition, assessment, solutions, and public acceptance. With respect to the actual well-being of the animal, most issues are centered on how the animal "feels" when managed within a specific level of confinement, during special agricultural practices (e.g., tail docking, beak trimming, etc.) and handling. Questions of this nature may require exploration of animal cognition, motivation, perception, and emotional states in addition to more commonly recognized indicators of well-being. Several general approaches have emerged for solving problems concerning animal well-being in intensive production systems: environmental, genetic, and therapeutic. Environmental approaches involve modifying existing systems to accommodate specific welfare concerns or development of alternative systems. Genetic approaches involve changing the behavioral and (or) physiological nature of the animal to reduce or eliminate behaviors that are undesirable within intensive system. Therapeutic approaches of a physical (tail docking, beak trimming) and physiological (drug and nutritional therapy) nature bring both concern and promise with regard to the reduction of confinement stress. Finally, the recent focus on commodity quality assurance programs may indirectly provide benefits for animal well-being. Although research in the area of animal well-being will provide important information for better animal management, handling, care, and the physical design of intensive production systems there is still some uncertainty regarding public acceptance. The aesthetics of modern intensive production systems may have as much to do with public acceptance as with science.

Review: welfare perspectives on hens kept for egg production.

The wild ancestors of chickens, along with those of most other farm animals, were preadapted to domestication because their lack of specialized requirements allowed them to adapt to a wide variety of environments provided by humans. Currently most commercial chickens kept for table-egg production are incubated, reared, and maintained as productive adults in high-density, artificial environments. Nevertheless, there are limits to adaptability as indicated by behavioral, physiological, immunological, and individual productivity indicators when environmental conditions become extreme. However, with the exception of obvious injury, no single criterion is likely to be adequate. Multiple indicators are required to obtain reliable evaluation of whether husbandry practices and environmental conditions reduce hens' welfare significantly. Concern for the well-being of hens has led to the phasing out of cages in two European countries. Although cages are known to be associated with some problems of well-being, it is known also that they have some welfare advantages for hens over alternative systems of production and they have definite economic advantages for producers. Therefore, it is doubtful whether the use of cages should be denied without exploring further the possibilities of cage modification or genetic selection aimed at improving the well-being of hens in such environments. Ethical perspectives relative to animals have been evolving since the time of Aristotle more than 300 yr B.C. Recent developments include divergence of welfare concerns between utilitarian and animal rights based philosophies. The utilitarians generally agree that animals may be used for human benefit if unnecessary pain and suffering are avoided and humane care and management criteria are met. Fundamentally, rights-oriented groups reject such exploitation. The general public exhibits a continuum of attitudes towards animals. However, there are indications that they are moving towards a protectionist attitude toward farm animals. Many requirements for good husbandry are known. However, uncertainty prevails in some areas, particularly with the necessity of routine procedures such as beak trimming and the amount of space needed, optimal group size, and whether nests, roosts, litter, and other quality of environment features are necessities or luxuries in terms of hens' welfare. Floor and feeder space and group size seem to be of paramount importance, and space that is adequate for well-being seems to be greater than that which yields the greatest net income. Genetic solutions to several behavior-related problems that compromise hens' well-being seem to be feasible and worthy of greater emphasis by commercial poultry breeders.

Prothrombin biosynthesis: characterization of processing events in rat liver microsomes.

Plasma and hepatic microsomal forms of rat prothrombin have been compared by sodium dodecyl sulfate-polyacrylamide electrophoresis and isoelectric focusing. The major prothrombin species that accumulated in the microsomes of rats treated with warfarin had a molecular weight of 78 500 and a pI in 8 M urea of 6.3-6.5. Plasma prothrombin had a molecular weight of 83 500 and a pI of 5.3-5.7. Microsomes from normal rat liver contain a second pool of precursor with a molecular weight of 83 500, and digestion with the glycosidase Endo H indicated that this form has been processed to contain complex carbohydrates, while the Mr 78 500 form is a high mannose form and is the substrate for the vitamin K dependent carboxylase. Treatment of rats with tunicamycin revealed that glycosylation was not essential for carboxylation or secretion from the liver. Comparison of the aglyco forms of prothrombin and its precursors suggests that the intracellular forms contain a basic, Mr approximately 1500 peptide that is missing from the plasma form of prothrombin.