Willard C Losinger

Management practices associated with high mortality among preweaned dairy heifers

In a national survey of US dairy operations, 1685 dairy operations reported 47,057 new dairy heifers (either births or acquisitions) and 4427 deaths (9.4%) of preweaned dairy heifer calves over a 3 month period. Stepwise logistic regression was used to identify management practices associated with high mortality among preweaned heifers in dairy operations where at least three dairy heifer calves were born alive or moved on to the operation. Analysis was done twice: once by separating all operations by size into high or low mortality; again using only operations with < 2 and > 10% mortality to eliminate dairy operations with intermediate levels of mortality from the comparisons. Results were similar. Dairy operations in the West were more likely to fall in the high mortality category than dairy operations in the rest of the country. In addition, the following dairy operation characteristics were associated with high death levels in both models: rolling herd average milk production < 7710 kg. preweaned heifers placed in groups of seven or more, a male having primary responsibility for the care and feeding of preweaned heifers, calves not receiving hay or other roughages until > 20 d old, calves fed on mastitic or antibiotic milk after colostrum and calves not given whole milk after colostrum.

Economic impact of reduced milk production associated with Johne's disease on dairy operations in the USA

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 Johnes disease indicated that reduced milk production, associated with the determination of dairy operations as Johnes-positive, reduced consumer surplus by 770 million dollars+/- 690 million dollars, and resulted in a total loss of 200 million dollars+/- 160 million dollars 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 dollars+/- 550 million dollars as a result of the reduced milk production associated with Johnes disease. Uncertainty analysis showed that the estimated reduction in milk production on Johnes-positive dairy operations accounted for most of the uncertainty in the economic-impact estimates. If Johnes 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 dollars+/- 560 million dollars.

Economic impacts of reduced milk production associated with papillomatous digital dermatitis in dairy cows in the USA.

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 Dollars 750 million +/- Dollars 580 million, and to increase the economic surplus of producers by Dollars 560 million +/- Dollars 470 million, with a net economic loss of Dollars 190 million +/- Dollars 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.

Management and nutritional factors associated with the detection of Salmonella sp. from cattle fecal specimens from feedlot operations in the United States

In a convenience sample of 100 feedlot operations (included in the United States Department of Agriculture: Animal and Plant Health Inspection Service 1994 Cattle on Feed Evaluation), up to 25 cattle fecal samples were collected and tested for the presence of Salmonella from each of two pens (the pen which contained the most-recent arrivals, and the pen with cattle that had been on feed the longest). One or more Salmonella spp. were recovered from 38 (38.0%) of the 100 feedlots, 52 (26.0%) of the 200 pens and 273 (5.5%) of the 4977 fecal samples collected. Multivariable logistic regression indicated that feeding tallow and feeding whole cottonseed or cottonseed hulls within seven days prior to fecal sample collection was associated with an increased risk of finding Salmonella in a pen. Variables not found to be significantly associated with the detection of Salmonella in a pen included region, operation size, use of sprinklers, time on feed, type of cattle in the pen, number and concentration of cattle in a pen, feeding probiotics, and various other feeds.

An analysis of mortality in the grower/finisher phase of swine production in the United States

Over a 6-month period, the mean mortality risk (based on 393 operations participating in the United States National Animal Health Monitoring System 1995 National Swine Study, and representing operations with > or = 300 market hogs in 16 states), was 2.3 +/- 0.2% in the grower/finisher production phase (where figures after the +/- represent the standard error of the estimate). Mortality > or = 4% was experienced by 13.5 +/- 2.9% of grower/finisher operations, while 63.6 +/- 5.3% had < or = 2% mortality. To identify factors associated with > or = 4% mortality, stepwise logistic regression [Statistical Analysis Systems, 1989. SAS/STAT Users Guide, Version 6, 4th edn, Vol. 2. SAS Institute, Cary, NC, 794 pp.] was performed twice: once using operations with all mortality rates, and again excluding operations with between 2% and 4% mortality. Final models were run with SUDAAN [Shah, B.V., Barnwell, B.G., Bieler, G.S., 1996. SUDAAN Users Manual, Version 6.40, 2nd edn. Research Triangle Institute, Research Triangle Park, NC, 492 pp.] to take the sample design into account. In addition, SAS and SUDAAN logistic regression models were developed to analyze factors associated with > 2.3% mortality among grower/finisher pigs. Mean weaning age < or = 28 days entered all models as being associated with increased mortality in the grower/finisher unit. Not obtaining all grower/finisher pigs from farrowing units belonging to the operation was associated with > or = 4% mortality among grower/finisher swine. Not typically giving grower/finisher pigs antibiotics or other agents as disease-preventives or growth-promotants in the feed or water, and ranking producer organizations as very or extremely important sources of antibiotic information were associated with < or = 2.3% mortality in the grower/finisher phase.

Design and implementation of the United States National Animal Health Monitoring System 1995 National Swine Study.

The United States Department of Agricultures National Animal Health Monitoring System 1995 National Swine Study was designed to estimate management, health and productivity parameters on pig operations in the United States. Sixteen major swine-producing states that accounted for nearly 91% of June 1, 1995 swine inventory and nearly three-fourths of United States swine producers were included in the study. In the initial phase of the study, National Agricultural Statistics Service enumerators collected information from 1477 producers involved in all phases of swine production (farrowing, nursery, and grower/finisher). Of these, 405 operations with > or = 300 finisher pigs (with at least one finisher pig > or = 54 kg) participated in the subsequent component of the study, which involved on-farm visits by state and federal veterinary medical officers and animal health technicians, and which concentrated on the grower/finisher phase of production. Of those eligible to take part in the second phase of the study, participation was higher among independent producers (48.3%) than among contract producers (15.3%). Participation was also higher among operations that used advanced record-keeping systems (such as record cards for individual breeding hogs or a computer-based record-keeping system). Thus, study results could have been influenced by response biases. As a biosecurity measure, 40.5 +/- 2.1% of operations restricted entry to employees only. For operations that permitted non-employees to enter the premises, relatively few enforced other biosecurity measures on visitors (0.4 +/- 0.1% required feed-delivery personnel and livestock handlers to shower before entering the premises; 3.3+/- 0.9% required a footbath; and 7.0 +/- 1.5% required feed-delivery personnel and livestock handlers not to have visited another operation with pigs on that day). The most common method of waste storage (used by 49.9 +/- 3.8% of operations with > or = 300 finisher pigs) was below-floor slurry or deep pit.

Economic impacts of reduced milk production associated with epidemiological risk factors for Johne's disease on dairy operations in the USA

An examination of the economic effects of epidemiologic risk factors for Johnes 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.

Mortality attributed to respiratory problems among finisher pigs in the United States.

In the 1995 National Swine Study of the United States National Animal Health Monitoring System, producers identified respiratory problems as the leading cause of death in pigs during the grower/finisher phase of production. Over a six-month period, 61.7 +/- 4.1% (mean +/- SEM) of operations reported at least one death attributed to respiratory problems among finisher pigs (based on 388 operations representing operations with > or = 300 finisher pigs in 16 states). Mean mortality attributed to respiratory problems was 0.9 +/- 0.1% of finisher pigs per operation. Stepwise logistic regression (using SAS) was used to identify factors associated with operations attributing at least one death to respiratory problems, and to identify factors associated with reporting > or = 2% mortality attributed to respiratory problems. Final models were run with SUDAAN to account for the sampling strategy. Attributing at least one death to respiratory problems was associated with having > or = 3000 pigs enter the grower/finisher unit over a six-month period; diagnosis of Haemophilus (or Actinobacillus) in the past 12 months; and keeping pigs in the grower/finisher unit > 120 days (as compared to < 100 days). Not having a farrowing facility, mean weaning age < 28 days, and < 50% of finisher pigs on solid concrete only were associated with reporting > or = 2% mortality attributed to respiratory problems.

Design and implementation of the United States National Animal Health Monitoring System 1994–1995 Cattle on Feed Evaluation, and an evaluation of the impact of response biases

The 1994-95 Cattle on Feed Evaluation was a cooperative project (sponsored by the United States Department of Agriculture) involving Washington State University, state agricultural departments, and several agencies of the United States Department of Agriculture). The project focused on cattle-on-feed operations in 13 states that accounted for over 85% of the United States cattle on feed inventory. Participants were selected from National Agricultural Statistics Service list frames. Questionnaires were administered by telephone to operations with a one-time capacity of fewer than 1000 cattle; larger operations were visited twice to administer questionnaires. The participation rate for the first phase of the study was 56.7%. Ninety-one percent of eligible operations completed the second phase of the study. Data summarized from this national study can be used to profile management practices on cattle-feeding operations in the United States. Differences between participants and non-participants did not appear to be great. However, one does need to be mindful of the fact that a small percentage of the producers accounted for the vast majority of feedlot cattle marketed when interpreting the results.

Welfare effects of the use of recombinant bovine somatotropin in the USA

The welfare effects of increased milk production associated with the use of recombinant bovine somatotropin (rBST) on dairy operations in the USA were examined for 1996. Results that derived from three different estimates of the milk-production response to rBST were evaluated and compared. One estimate, derived from a survey of dairy producers in Connecticut, led to economic-impact estimates that were not statistically significant. A second, derived from a national survey that concentrated on the health and management of dairy cattle, led to estimates that were unbelievably high. A third, derived from a national survey that concentrated on the economics of dairy producers, provided the most reasonable estimates of economic impacts. Results of economic analysis, using the latter results, indicated that if rBST had not caused milk production to increase, then the market price of milk would have been 2.2 +/- 1.5 cents/kg higher, and the total value of the milk produced would have risen from Dollars 23.0 +/- 0.6 billion to Dollars 24.1 +/- 1.0 billion. A welfare analysis demonstrated that the increased milk production (and the reduced market price) associated with the use of rBST in the USA caused the economic surplus of consumers to rise by Dollars 1.5 +/- 1.0 billion, while the economic surplus of dairy producers fell by Dollars 1.1 +/- Dollars 0.8 billion. Increased milk production associated with rBST yielded a total gain to the US economy of Dollars 440 +/- 280 million. An analysis of annual percent changes in the number of dairy cows per operation, milk production per cow, total milk production, total number of dairy cows, and total number of dairy operations in the USA suggested that the dairy industrys long-term economic growth path was stable from 1989-2001 inclusive, and did not receive a shock resulting from the introduction of rBST.