Managing for improved dairy cow health (Proceedings)

Over the last several decades we have witnessed tremendous changes in dairy production systems. A traditional concept that the food animal practitioner could focus primarily on traveling to farms and treating diseased animals has long since been overshadowed by a more complex picture. Dramatic changes have been made in management, nutrition and genetics of our cattle population, in order to increase productivity. Our profession has responded by moving towards 'production oriented' practices, and has changed its view of the importance of certain types of animal problems. We increasingly recognize the importance of suboptimal performance that occurs without overt disease, the occurrence of metabolic and production related diseases and a variety of management problems that limit operation profitability.

Ongoing scientific advancements have also influenced our perception of infectious diseases and our methods of dealing with them. It has been easy for some of us to assume that vaccine improvements make infections ever more preventable, and antibiotic improvements make these diseases ever more treatable. The extent to which our profession seems to have bought into these assumptions is sobering.

It appears that there are numerous health challenges on modern dairies that leave cows at high risk of subsequent culling or death as likely outcomes. The reasons for removal of cows for slaughter are closely related to the causes of death, and most of these are representative of health issues that can be improved.

There are some subclinical metabolic or physiologic problems faced by many cows in modern dairy systems that could predispose to poor outcomes in the face of disease challenges. These include subclinical hypocalcemia, subacute ruminal acidosis, negative energy balance and metabolic disease in early lactation, trace mineral and vitamin deficiency, poor immune responsiveness in the postpartum period, and feed quality problems that induce gastrointestinal disturbances.

Other studies have identified clinically recognizable health problems that increase the risk of death or culling in dairy cows, such as calving difficulty, ketosis/fatty liver disease, coliform mastitis, milk fever, and paratuberculosis. The severity of these diseases in individual animals is highly influential on the outcome. Since most dairy health programs do not monitor or analyze the severity or impact of these diseases, dairies lack the tools needed to associate occurrence with final outcome and may fail to manage the problems appropriately. Differences in outcomes for individual cows may result from failure to apply readily available evaluation and treatment methods appropriate to the specific disease and severity of disease.

Most changes in the dairy industry are done with the intent to decrease cost of inputs into the system. Some examples include increased size and scale of dairy operations, changes in the labor and labor management inputs, changes in veterinary relationship with the dairy. Without question, these changes that increased overall dairy productivity and maintained decreased cost input relative to the overall production.

Most decisions in a low-cost production model are made with economics is the primary driving force, and potential negative impacts on the animals in the production system are seen as problems that must be managed as a consequence of the necessary change. And in fact numerous animal health problems remain prevalent, and even increase with time. There is a real need for the dairy industry and dairy veterinarians to reevaluate dairy management systems with a focus on optimum animal health.

A different business model may be required for improvement of animal well-being on dairies, while maintaining dairy profitability. Total quality management is a business system that has been adopted by almost all industrial and manufacturing systems in the United States. Adopting such a business model would require a significant shift in mindset of producers and veterinarians. It should also provide increased balance in decision-making with animal well-being included as a significant component of productivity.

An overview of the health challenges faced by dairy cows needs to recognize that changes in the modern dairy industry could lead to systematic problems with animal care. The labor force on most dairies is primarily composed of low wage workers without extensive, preexisting dairy cow management skills. The ability of dairy personnel to adequately identify disease in individual animals and respond with prompt individual animal attention is limited by the extent of their experience and training. The overwhelming majority of sick cows on dairies are identified, diagnosed, and treated by farm workers, rather than veterinarians. Poor outcomes could be an issue of poor clinical disease management in addition to any preexisting problem with cow physiology.

Necropsy examination of dead animals to assess and monitor cause of death is rarely performed on dairies. This is in sharp contrast to other intensive livestock management systems, including poultry, swine, and feedlot enterprises, where necropsy monitoring is routine. Most dairy veterinarians focus considerable effort on dairy reproduction, but little time on mortality evaluation. This presents a very significant liability to the dairy industry because efforts to effectively decrease mortality losses are hampered by a lack of monitoring and information that provide accurate assessment of the problem. We believe that dairy workers could be trained to more effectively monitor death losses, and to perform on-farm necropsy examinations in consultation with veterinarians when the veterinarian cannot be present to perform the examination on a freshly dead carcass. We have presented this recommendation to producer groups and produced an on-line training program for that purpose on our website at http://www.cvmbs.colostate.edu/ilm/outreach/necropsy/_notes/index.html Very few producers or veterinarians have pursued this approach, attesting to the notion that monitoring actual cause of death has not been seen as a valuable pursuit.

Because of the complex nature of dairy management systems it is likely that a variety of causes are responsible for high disease and mortality rates, with different rates of occurrence on different operations. The wide range of lactational incidence risk for common diseases (milk fever: 0.03%-22.3%, RP: 1.3 – 39.2%, metritis: 2.2-37.3%, ketosis: 1.3-18.3%, LDA: 0.3-6.3, lameness: 1.8-30%) attests to the complexity of the system. To adequately address such a complex problem requires more accurate information about current losses, followed by management alterations that address the underlying problems. This will require changing the nature of information used in dairy management systems. An example of mastitis prevalence can illustrate this point. The specific infectious organism that causes a clinical mastitis episode can have a dramatic impact on outcome, and appropriate preventative or therapeutic measures need to be tailored to the specific cause, e.g. gram negative vs. gram positive, environmental vs. contagious, Escherichia coli vs. Staphylococcus aureus.28 Assessments and record systems that track "mastitis" without identifying other specific details do not provide sufficient information to promote effective interventions. Similarly, monitoring death losses with generic terms such as "lameness" or "mastitis" and performing this monitoring on the basis of presumption will not allow correction of management problems that may underlie the death.

Traditionally we have relied on the scrutiny and measurement of certain aspects of the product, or product quality control. When product defects are found, then we troubleshoot and try to solve problems reactively. Quality assurance puts the emphasis on process quality assurance, with systematic, proactive methods to do a procedure in a high quality manner. Assuring the quality of these processes, and the various inputs to the product, more effectively guarantees a high quality result, and this will hold true for all phases of the operation, not just the final step of milk production and sale. The benefits of assuring process quality have included decreased production costs, increased productivity, reduced defects and consumer complaints, thus improved consumer confidence and a competitive advantage in product marketing. Components of a TQM program for dairy production would include education of the workers in the system, monitoring of processes that are used, and monitoring of outcomes to identify trends. These are very different activities than most dairy veterinarians have used in their approach to herd health.