In 1991, USDA's National Animal Health Monitoring System (NAHMS) conducted its first dairy study, a baseline assessment that focused on the health and management of heifer calves. During the study, producers ranked respiratory disease among the top two most common health problems affecting dairy calves. Over the last 25 years, U.S. dairy producers have participated in six NAHMS studies, yielding a rich repository of information that has helped identify needs for research, extension, and education in the dairy industry. NAHMS’ most recent dairy study, conducted in 2014, provides the latest estimates on dairy cattle health and includes another in-depth look at heifer-calf health. While overall mortality in calves has decreased, bovine respiratory disease (BRD) remains an important cause of morbidity in calves. This raises the concern that BRD mitigation may be at a standstill on dairies. Research and on-farm experience have done much to elucidate the challenges associated with detection and perceived impacts of this complex disease. Continued development and implementation of new methods for monitoring health and detecting disease will provide additional tools to upend stalemating factors associated with BRD control, helping the dairy industry ‘turn a corner’ on this important disease.

The USDA:APHIS National Animal Health Monitoring System collects data on health and health management in livestock and poultry populations throughout the USA in order to provide stakeholders with population estimates to use as benchmarks for comparison, to guide policy development, and to identify research needs and prioritize education efforts. Recent studies of both the beef cattle feedlot industry and dairy heifer rearing operations provided information about BRD occurrence as well as information about prevention and treatment practices used on these operations. While a great deal of effort is dedicated to BRD prevention, there are still opportunities to improve the strategies used. Despite efforts to prevent the disease, BRD continues to be widespread on both of these types of operations.

The goal of this study was to measure the economic impacts of reduced milk production associated with papillomatous digital dermatitis (PDD) in dairy cows in the USA, and of specific risk factors for PDD, in 1996. The method applied was an economic-welfare analysis of producer and consumer surplus, with the GUM Workbench used to analyse uncertainties in the measurements. Reduced milk production associated with PDD was found to reduce consumer surplus by $750 million±$580 million, and to increase the economic surplus of producers by $560 million±$470 million, with a net economic loss of $190 million±$130 million. An examination of the economic effects of specific epidemiologic risk factors for PDD showed that having dairy cows that were not born on the operation had important economic consequences associated with the disease, as did the type of land to which dairy cows had access during the winter months and the type of flooring on which cows walked. Washing hoof-trimming equipment between cows was an important biosecurity measure that was associated with reduced PDD. The epidemiologic model used also implicated hoof trimmers who trimmed cattle hooves on other operations as having an important economic impact associated with this disease, although this finding may have been erroneous.

An examination of the economic effects of epidemiologic risk factors for Johne's disease identified regional and herd size differences as having the greatest impact. Having dairy cows that were not born on the operation was the most important factor over which individual producers had the most immediate control. Economic consequences associated with using multiple-cow-maternity housing and multiple-preweaned-calf housing were not statistically significant. Economic welfare analysis was applied, and the GUM Workbench was used to analyse uncertainties in the estimates of the economic impacts.

Accurately assessing the economic impacts of diseases and other factors that affect milk production requires that the demand for milk be taken into account. Because demand for milk in the USA is relatively inelastic (i.e., consumers generally purchase a somewhat fixed amount over a given time frame, regardless of fluctuations in price), consumers tend to reap much of the benefit of enhanced production. An examination of the economic impacts of Johne's disease indicated that reduced milk production, associated with the determination of dairy operations as Johne's-positive, reduced consumer surplus by $770 million ± $690 million, and resulted in a total loss of $200 million ± $160 million to the US economy in 1996. Most of the economic surplus lost by consumers was transferred to producers, whose economic surplus increased by $570 million ± $550 million as a result of the reduced milk production associated with Johne's disease. Uncertainty analysis showed that the estimated reduction in milk production on Johne's-positive dairy operations accounted for most of the uncertainty in the economic-impact estimates. If Johne's disease had not been present on US dairy operations, then an additional 580 million ±460 million kg of milk would have been produced, but the price would have fallen by 1·1±1·0 cents/kg, and the total value of the milk would have decreased by $580 million ± $560 million.