Factors Associated with Shiga Toxin-Producing Escherichia coli Shedding by Dairy and Beef Cattle.

UNLABELLED: Shiga toxin-producing Escherichia coli (STEC) is an important foodborne pathogen that can cause hemorrhagic colitis and hemolytic-uremic syndrome. Cattle are the primary reservoir for STEC, and food or water contaminated with cattle feces is the most common source of infections in humans. Consequently, we conducted a cross-sectional study of 1,096 cattle in six dairy herds (n = 718 animals) and five beef herds (n = 378 animals) in the summers of 2011 and 2012 to identify epidemiological factors associated with shedding. Fecal samples were obtained from each animal and cultured for STEC. Multivariate analyses were performed to identify risk factors associated with STEC positivity. The prevalence of STEC was higher in beef cattle (21%) than dairy cattle (13%) (odds ratio [OR], 1.76; 95% confidence interval [CI], 1.25, 2.47), with considerable variation occurring across herds (range, 6% to 54%). Dairy cattle were significantly more likely to shed STEC when the average temperature was >28.9°C 1 to 5 days prior to sampling (OR, 2.5; 95% CI, 1.25, 4.91), during their first lactation (OR, 1.8; 95% CI, 1.1, 2.8), and when they were <30 days in milk (OR, 3.9; 95% CI, 2.1, 7.2). These data suggest that the stress or the negative energy balance associated with lactation may result in increased STEC shedding frequencies in Michigan during the warm summer months. Future prevention strategies aimed at reducing stress during lactation or isolating high-risk animals could be implemented to reduce herd-level shedding levels and avoid transmission of STEC to susceptible animals and people. IMPORTANCE: STEC shedding frequencies vary considerably across cattle herds in Michigan, and the shedding frequency of strains belonging to non-O157 serotypes far exceeds the shedding frequency of O157 strains, which is congruent with human infections in the state. Dairy cattle sampled at higher temperatures, in their first lactation, and early in the milk production stage were significantly more likely to shed STEC, which could be due to stress or a negative energy balance. Future studies should focus on the isolation of high-risk animals to decrease herd shedding levels and the potential for contamination of the food supply.

Herd-level determinants of bovine leukaemia virus prevalence in dairy farms.

The prevalence of bovine leukaemia virus (BLV) was determined in 113 Michigan dairy herds by ELISA testing for anti-BLV antibodies in milk. Additionally, an interview regarding management practices with cooperating herd managers identified farm-level variables thought to be associated with prevalence of BLV. Twenty-three risk factors (P ≤ 0·1) were identified on one-way ANOVA or simple linear regression. Multivariate analysis identified several management practices whose predictive value for increased prevalence of BLV may relate to transmission among herd mates, e.g. reuse of hypodermic needles, lack of fly control, gouge dehorning and increased use of injections in dry cows. Additionally, exclusive breeding of heifers with artificial insemination was associated with decreased BLV prevalence, as compared with at least some use of natural service by a bull. Although intervention studies are needed before causal relationships can be concluded, and unaccounted variables related to transmission exist among dairy herds, these findings suggest management practices that may help dairy producers reduce the transmission of BLV within their herds.

The effect of bovine leukemia virus on dairy cow longevity.

Bovine leukemia virus (BLV) is a retrovirus of cattle that infects approximately 45% of all US dairy cattle, with about 90% of US dairy herds having at least one infected animal. Studies have found BLV infection to be associated with multiple measures of decreased immune function, which may explain the observed economic losses from milk production, decreased cow longevity, and predisposition to lymphoma and other diseases. Our objective was to measure the association between BLV infection and cow longevity in dairy cow operations. Ninety-one dairy herds from 9 US states volunteered to participate in this study. Milking dairy cows (n = 3,611) were tested for BLV antibodies using an ELISA milk test, and their presence in the herd was monitored for an average of 29 mo. The survival analysis controlled for herd and lactation number. Cows sold for dairy purposes were excluded, and individual cow results were not shared with producers so as not to influence culling decisions. Overall, 47.1% (1,701/3,611) of cows were BLV-positive by ELISA. The significant hazard ratio of 1.30 indicated that positive cows were 30% more likely than their negative herdmates to die or be culled during the monitoring period. These results are consistent with other studies in finding a negative effect of BLV infection on cow lifespan.

Cross-sectional study to describe bovine leukemia virus herd and within-herd ELISA prevalence and bovine leukemia virus proviral load of convenience-sampled Kansas beef cow-calf herds.

OBJECTIVE: Determine bovine leukemia virus (BLV) seroprevalence of adult female cattle in Eastern Kansas beef herds and the proviral load (PVL) of those cattle found to be ELISA positive. ANIMALS: Convenience sample of 2,845 cows from 44 beef herds. PROCEDURES: BLV serostatus was determined using an ELISA antibody test (gp-51; IDEXX). BLV quantitative PCR (qPCR) status and PVL were determined utilizing a qPCR test (SS1 qPCR test; CentralStar Laboratories). The association of age, herd size, and body condition score (BCS) category on the probability of being BLV positive was evaluated with a multiple variable logistic regression analysis that used BLV status as a binary outcome, herd nested within ranch as a random effect, and BCS, herd size, and age category as fixed effects. RESULTS: Forty-two of 44 herds had at least 1 BLV ELISA-positive cow (95.5% herd seroprevalence). Overall, 1,564 of the 2,845 cows were BLV ELISA positive (55.0% individual animal prevalence). No association between BLV ELISA status and herd size or BCS was identified. When evaluated by age, the model-adjusted probability of being BLV ELISA positive was lowest for heifers (1 year of age, first parity) and increased until 5 to 6 years of age. Of the 1,564 ELISA-positive animals, 838 were qPCR positive (53.6%). The model-adjusted probability of being qPCR positive was not associated with age, herd size, or BCS category. CLINICAL RELEVANCE: This study indicated that BLV-seropositive status both as a herd classification and individual animal classification was very common in this population. Because the percentage of BLV-seropositive cows varied between herds and by age, this study provides evidence that it is essential for investigators to control for herd and age in any analysis of the association of BLV serostatus and health and production outcomes of interest. Some BLV ELSIA-seropositive cows were classified as BLV negative by qPCR, and risk factors may differ between classification status by ELISA and qPCR.

Identification of BoLA Alleles Associated with BLV Proviral Load in US Beef Cows.

Bovine leukemia virus (BLV) causes enzootic bovine leukosis, the most common neoplastic disease in cattle. Previous work estimates that 78% of US beef operations and 38% of US beef cattle are seropositive for BLV. Infection by BLV in a herd is an economic concern for producers as evidence suggests that it causes an increase in cost and a subsequent decrease in profit to producers. Studies investigating BLV in dairy cattle have noted disease resistance or susceptibility, measured by a proviral load (PVL) associated with specific alleles of the bovine leukocyte antigen (BoLA) DRB3 gene. This study aims to investigate the associations between BoLA DRB3 alleles and BLV PVL in beef cattle. Samples were collected from 157 Midwest beef cows. BoLA DRB3 alleles were identified and compared with BLV PVL. One BoLA DRB3 allele, *026:01, was found to be associated with high PVL in relation to the average of the sampled population. In contrast, two alleles, *033:01 and *002:01, were found to be associated with low PVL. This study provides evidence of a relationship between BoLA DRB3 alleles and BLV PVL in US beef cows.

Phenotypic Selection of Dairy Cattle Infected with Bovine Leukemia Virus Demonstrates Immunogenetic Resilience through NGS-Based Genotyping of BoLA MHC Class II Genes.

Characterization of the bovine leukocyte antigen (BoLA) DRB3 gene has shown that specific alleles associate with susceptibility or resilience to the progression of bovine leukemia virus (BLV), measured by proviral load (PVL). Through surveillance of multi-farm BLV eradication field trials, we observed differential phenotypes within seropositive cows that persist from months to years. We sought to develop a multiplex next-generation sequencing workflow (NGS-SBT) capable of genotyping 384 samples per run to assess the relationship between BLV phenotype and two BoLA genes. We utilized longitudinal results from milk ELISA screening and subsequent blood collections on seropositive cows for PVL determination using a novel BLV proviral load multiplex qPCR assay to phenotype the cows. Repeated diagnostic observations defined two distinct phenotypes in our study population, ELISA-positive cows that do not harbor detectable levels of provirus and those who do have persistent proviral loads. In total, 565 cows from nine Midwest dairy farms were selected for NGS-SBT, with 558 cows: 168 BLV susceptible (ELISA-positive/PVL-positive) and 390 BLV resilient (ELISA-positive/PVL-negative) successfully genotyped. Three BoLA-DRB3 alleles, including one novel allele, were shown to associate with disease resilience, *009:02, *044:01, and *048:02 were found at rates of 97.5%, 86.5%, and 90.3%, respectively, within the phenotypically resilient population. Alternatively, DRB3*015:01 and *027:03, both known to associate with disease progression, were found at rates of 81.1% and 92.3%, respectively, within the susceptible population. This study helps solidify the immunogenetic relationship between BoLA-DRB3 alleles and BLV infection status of these two phenotypic groupings of US dairy cattle.

Developing an open-access antimicrobial resistance learning site for veterinary medical students.

Recognizing the crucial role of veterinarians in mitigating antimicrobial resistance (AMR), the Centers for Disease Control and Prevention (CDC) has funded the development of a suite of educational materials to promote the responsible veterinary medical use of antimicrobials. An open-access, Web-based multimedia curriculum regarding antimicrobial resistance in veterinary practice was thus created. The antimicrobial-resistance learning site (AMRLS) for veterinary medical students was completed and made available for use in January 2011 (http://amrls.cvm.msu.edu/). Designed for integration into existing veterinary medical courses, the AMRLS is also a resource for continuing education for practicing veterinarians, animal scientists, and food-animal industry specialists. This Web site emphasizes the mechanisms by which AMR emerges and spreads, the significant role of veterinarians in mitigating AMR, and the need to preserve the efficacy of antibiotics for future generations.

Diagnostic Measures of Disease Progression in Cattle Following Natural Infection with Bovine Leukemia Virus.

This study describes the longitudinal changes in bovine leukemia virus (BLV) ELISA antibodies, proviral load (PVL), and blood lymphocyte counts (LC) observed over a 2.5-year period in naturally infected cattle. The dataset utilized was from a BLV intervention field trial on three Midwestern dairy herds. Our analysis showed ELISA false negatives were more likely to occur in cattle with low PVL and normal LC. On average, negligible changes in LC were observed during six-month intervals. Periods of lymphocytosis, defined as >10,000 lymphocytes per uL of blood, were observed in 31.5% (68/216) of BLV test-positive cattle. In BLV test-positive cows, an average increase of 2900 to 3100 proviral copies per 100,000 cells was observed during each subsequent six-month sampling interval. The difference between the minimum and maximum PVL observed for an ELISA-positive cow with 3 or more observations ranged from 0 to 115,600 copies per 100,000 cells (median: 12,900; mean: 19,200). Therefore, following the identification of ELISA-positive cattle and the assessment of PVL and LC, subsequent semiannual tests to assess disease progression may not be needed. Further work is needed to determine how available diagnostic tests can be optimized to design cost-effective testing schemes for BLV control programs.

Natural Infection of Dairy Cows with Bovine Leukemia Virus Affects Immunoglobulin Levels in Saliva and Serum but Not Milk.

Bovine leukemia virus (BLV) is a retroviral infection that disrupts the immune function of infected animals. It is widespread among U.S. dairy cattle. In this pilot study, the average total IgA and IgM concentrations in milk, saliva, and serum samples from BLV ELISA-positive (ELISA+) dairy cows were compared against samples from BLV ELISA-negative (ELISA-) cows using the Kruskal-Wallis test (with ties). The results from ELISA+ cows were also stratified by lymphocyte count (LC) and proviral load (PVL). In milk and saliva from ELISA+ cows, the average total IgA and IgM concentrations were decreased compared to ELISA- cows, although this was only statistically significant for saliva IgM in cows with low PVL (p = 0.0424). Numerically, the average total IgA concentrations were 33.6% lower in milk and 23.7% lower in saliva, and the average total IgM concentrations were 42.4% lower in milk and 15.5% lower in saliva. No significant differences were observed in the total serum IgA concentrations, regardless of PVL and LC. The total serum IgM from ELISA+ cows was significantly decreased (p = 0.0223), with the largest decreases occurring in the highest PVL and LC subgroups. This pilot study is a first step in investigating the impact of BLV on mucosal immunity and will require further exploration in each of the various stages of disease progression.

Effect of changes in number of doses and anatomic location for administration of an Escherichia coli bacterin on serum IgG1 and IgG2 concentrations in dairy cows.

OBJECTIVE: To determine effects of injection site on antibody response to J5 Escherichia coli bacterin. ANIMALS: 28 adult Holstein cows. PROCEDURES: Cows were randomly assigned as control cattle (n = 4 cows), not administered J5 E coli bacterin; 3X (8), administered 3 doses of bacterin SC in the left side of the neck; 5XN (8), administered 5 doses of bacterin SC in the left side of the neck; or 5XSR (8), administered 5 doses of bacterin SC sequentially in the left side of the neck, right side of the neck, right side of the thorax, left side of the thorax, and left side of the neck. Blood samples were collected from the cows to determine anti-J5 E coli IgG1 and IgG2 concentrations. RESULTS: Vaccinated cows had higher mean serum anti-J5 E coli IgG1 concentrations than did control cows. The 5XN and 5XSR cows had higher mean serum anti-J5 E coli IgG1 concentrations than did 3X cows. Additionally, 5XSR cows had higher mean serum anti-J5 E coli IgG1 concentrations than did 5XN cows. Vaccinated cows had higher mean serum anti-J5 E coli IgG2 concentrations than did control cows. The 5XN and 5XSR cows had higher mean serum anti-J5 E coli IgG2 concentrations than did 3X cows. The 5XSR cows had higher mean serum anti-J5 E coli IgG2 concentrations than did all other groups at 84 days after the fifth vaccination. CONCLUSIONS AND CLINICAL RELEVANCE: Sequential doses of core-antigen bacterins administered at different anatomic locations may improve antibody response in dairy cattle.

Prevalence and patterns of antimicrobial resistance in Campylobacter spp isolated from pigs reared under antimicrobial-free and conventional production methods in eight states in the Midwestern United States.

OBJECTIVE: To compare apparent prevalence and patterns of antimicrobial resistance in Campylobacter spp in feces collected from pigs reared with antimicrobial-free versus conventional production methods in 8 states in the Midwestern United States. DESIGN: Cross-sectional study. SAMPLE POPULATION: 95 swine farms that used antimicrobial-free (n = 35) or conventional (60) production methods. PROCEDURES: Fecal samples from 15 pigs/farm were collected. Biochemical and multiplex-PCR analyses were used to identify Campylobacter spp. The minimal inhibitory concentrations of erythromycin, azithromycin, ciprofloxacin, nalidixic acid, gentamicin, and tetracycline for these organisms were determined by use of a commercially available antimicrobial gradient strip. The data were analyzed by use of population-averaged statistical models. RESULTS: Campylobacter spp were isolated from 512 of 1,422 pigs. A subset (n = 464) of the 512 isolates was available for antimicrobial susceptibility testing. The apparent prevalence of Campylobacter spp isolates from pigs on conventional farms (35.8%) and antimicrobial-free farms (36.4%) did not differ significantly. Resistances to azithromycin, erythromycin, and tetracycline were significantly higher on conventional farms (70.0%, 68.3%, and 74.5%, respectively) than antimicrobial-free farms (20.1%, 21.3%, and 48.8%, respectively). Resistances to azithromycin, erythromycin, and tetracycline declined as the number of years that a farm was antimicrobial-free increased. CONCLUSIONS AND CLINICAL RELEVANCE: Production method did not affect the apparent prevalence of Campylobacter spp on swine farms. However, antimicrobial-free farms had a significantly lower prevalence of antimicrobial resistance. Although cessation of antimicrobial drug use will lower resistance over time, investigation of other interventions designed to reduce resistance levels is warranted.

Impact of bovine leukemia virus infection on beef cow longevity.

Bovine leukosis is a chronic lymphoproliferative disorder caused by bovine leukemia virus (BLV). Previous studies estimate that 38 % of cow-calf beef herds and 10.3 % of individual beef cows in the US are BLV seropositive. About 70 % of BLV infected animals are asymptomatic carriers of the virus, while less than 5% develop lymphosarcoma, the leading reason for carcass condemnation at the US slaughterhouses. Studies provide evidence that BLV infection leads to decreased immune function making animals more vulnerable to other diseases, which could shorten their productive lifespan and increase economic losses in the cattle industry. BLV seropositive dairy cows are reportedly more likely to be culled sooner compared with their uninfected herd mates. Beyond simple prevalence studies, little is known about the impact of BLV infection in beef cattle production or specifically on beef cow longevity. Our objective was to determine the association between BLV infection and cow longevity in beef cow-calf operations. Twenty-seven cow-calf herds from the Upper Midwest volunteered to participate in this study. Female beef cattle (n = 3146) were tested for serum BLV antibodies by ELISA. A subsample of 648 cows were also tested for BLV proviral load (PVL). Culling data was collected for the subsequent 24 months. Twenty-one herds (77.7 %) had at least one BLV-infected animal, and 29.2 % (930/3146) of tested animals were BLV seropositive. Of the BLV-positive cows, 33.7 % (318/943) were culled compared with 32.1 % (541/1682) of the seronegative cows. BLV status did not affect cows' longevity within herds (P = 0.062). However, cows with high BLV PVL had decreased survival within the herd compared with ELISA- negative cows (P = 0.01). Overall, infection with BLV did not impact beef cow longevity unless the disease had progressed to a point of high BLV PVL.

Current Developments in the Epidemiology and Control of Enzootic Bovine Leukosis as Caused by Bovine Leukemia Virus.

Enzootic Bovine Leukosis (EBL) caused by the bovine leukemia virus (BLV) has been eradicated in over 20 countries. In contrast, the U.S. and many other nations are experiencing increasing prevalence in the absence of efforts to control transmission. Recent studies have shown that BLV infection in dairy cattle has a greater impact beyond the long-recognized lymphoma development that occurs in <5% of infected cattle. Like other retroviruses, BLV appears to cause multiple immune system disruptions, affecting both cellular and humoral immunity, which are likely responsible for increasingly documented associations with decreased dairy production and decreased productive lifespan. Realization of these economic losses has increased interest in controlling BLV using technology that was unavailable decades ago, when many nations eradicated BLV via traditional antibody testing and slaughter methods. This traditional control is not economically feasible for many nations where the average herd antibody prevalence is rapidly approaching 50%. The ELISA screening of cattle with follow-up testing via qPCR for proviral load helps prioritize the most infectious cattle for segregation or culling. The efficacy of this approach has been demonstrated in at least four herds. Breeding cattle for resistance to BLV disease progression also appears to hold promise, and several laboratories are working on BLV vaccines. There are many research priorities for a wide variety of disciplines, especially including the need to investigate the reports linking BLV and human breast cancer.

Bovine leukemia virus detection and dynamics following experimental inoculation.

Bovine leukemia virus (BLV) infects more than 40% of the United States cattle population and impacts animal health and production. Control programs aiming to reduce disease prevalence and incidence depend on the ability to detect the BLV provirus, anti-BLV antibodies, and differences in blood lymphocyte counts following infection. These disease parameters also can be indicative of long-term disease progression. The objectives of this study were to determine the timing and to describe early fluctuations of BLV-detection by qPCR, ELISA, and lymphocyte counts. Fifteen Holstein steers were experimentally inoculated with 100 µL of a blood saline inoculum. Three steers served as in-pen negative controls and were housed with the experimentally infected steers to observe the potential for contract transmission. Five additional negative controls were housed separately. Steers were followed for 147 days post-inoculation (DPI). Infections were detected in experimentally infected steers by qPCR and ELISA an average of 24- and 36 DPI, respectively. Significant differences in lymphocyte counts between experimentally infected and control steers were observed from 30 to 45 DPI. Furthermore, a wide variation in peak proviral load and establishment was observed between experimentally infected steers. The results of this study can be used to inform control programs focused on the detection and removal of infectious cattle.

Control of Bovine Leukemia Virus in Three US Dairy Herds by Culling ELISA-Positive Cows.

The objective of this trial was to evaluate a test-and-cull approach to controlling bovine leukemia virus (BLV) in US dairy herds with a low BLV prevalence. Despite worldwide distribution of the virus, 21 nations have eradicated BLV from their dairy cattle and are currently considered 'BLV-free.' In contrast, the US has attempted no industry-wide BLV control programs and has experienced an increase in BLV prevalence among dairy cows to about 40%. This raises concerns about production efficiency, herd health, and sustainability. In a pilot field trial with three Midwestern-US dairy herds, a test-and-cull approach using ELISA screening of milk samples was successful in reducing BLV prevalence in two herds. In the third herd, BLV prevalence increased following the introduction of infected heifers that were raised at an out-of-state calf raising facility. This trial demonstrated that a test-and-cull approach to BLV control can be successful in US dairy herds with low BLV prevalence, but ongoing surveillance is necessary to prevent reintroduction of the virus.

Lack of Bovine leukemia virus transmission during natural breeding of cattle.

Bovine leukosis is a chronic lymphoproliferative disorder that leads to significant economic losses in the beef and dairy industries. The major route of virus transmission is believed to be iatrogenic through the transfer of blood containing infected lymphocytes. In addition, BLV proviral DNA has been identified in nasal secretions, saliva, milk, colostrum, semen and smegma; however, natural transmission of BLV through these secretions has not been clearly demonstrated. The use of bulls for natural breeding has been identified as a risk factor in BLV infected dairy herds. However, the risk of BLV-infected bulls transmitting the virus is unknown. The objective of this study was to evaluate the potential for BLV transmission during natural breeding between a BLV-infected bull and uninfected heifers. Forty healthy, BLV seronegative, and proviral-negative beef heifers were randomly assigned to one of two groups: control heifers (n = 20) exposed to a BLV seronegative and proviral negative bull and challenged heifers (n = 20) exposed to a BLV seropositive and proviral-positive bull. Each group was housed with the bull for a period of 38 days in a 5-acre pasture to replicate the housing of commercial beef cattle during the breeding season. Blood samples were collected from heifers at -60, -30 and 0 days prior to breeding and day 30, 60 and 90 after the breeding period ended. Blood samples were tested for BLV antibodies by ELISA and BLV proviral DNA by CoCoMo-qPCR. New infection was not detected by ELISA or CoCoMo-qPCR in any of the challenge or control heifers at any time point during the study. Based on these results, BLV infected bulls that are healthy and aleukemic may not be a significant risk of BLV transmission during a defined breeding season.

Breeding bulls as a potential source of bovine leukemia virus transmission in beef herds.

OBJECTIVE: To determine the prevalence of bovine leukemia virus (BLV) in beef bulls; evaluate the presence of BLV provirus DNA in blood, smegma, and semen samples; and analyze whether blood BLV proviral load was associated with differential blood cell counts. DESIGN: Observational cross-sectional study. ANIMALS: 121 beef bulls ≥ 2 years old from 39 Michigan herds. PROCEDURES: Blood, smegma, and semen samples were collected from each bull during a routine breeding soundness examination. An ELISA was used to detect serum anti-BLV antibodies. A coordination of common motifs-quantitative PCR assay was used to detect BLV provirus DNA in blood, smegma, and semen samples. Bulls with positive results on both the BLV serum ELISA and coordination of common motifs-quantitative PCR assay were considered infected with BLV. RESULTS: 19 of 39 (48.7%) herds and 54 of 121 (44.6%) bulls were infected with BLV. Provirus DNA was detected in the blood of all 54 and in smegma of 4 BLV-infected bulls but was not detected in any semen sample. Lymphocyte count was significantly greater in BLV-infected bulls than in uninfected bulls. The proportion of BLV-infected bulls with lymphocytosis (16/54 [29.6%]) was greater than the proportion of uninfected bulls with lymphocytosis (6/67 [9%]). Lymphocyte count was positively associated with BLV proviral load in BLV-infected bulls. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that almost half of beef bulls and herds were infected with BLV, and BLV provirus DNA was detected in the smegma of some BLV-infected bulls. Bulls may have an important role in BLV transmission in beef herds.

Human Mycobacterium bovis infection and bovine tuberculosis outbreak, Michigan, 1994-2007.

Mycobacterium bovis is endemic in Michigan's white-tailed deer and has been circulating since 1994. The strain circulating in deer has remained genotypically consistent and was recently detected in 2 humans. We summarize the investigation of these cases and confirm that recreational exposure to deer is a risk for infection in humans.

Factors influencing the survival of dairy cows after correction of left displaced abomasum.

OBJECTIVE: To determine factors that influenced culling or death of cows with left displaced abomasum (LDA) subsequent to correction by a roll-and-toggle (R&T) procedure or via laparotomy. DESIGN: Cohort study. ANIMALS: 810 Holstein dairy cows with LDA. PROCEDURES: Data regarding method of repair and risk factors for survival after correction of LDA were collected during a 1-year period. Outcomes were compared at days 14 and 60 after LDA correction for 3 groups of cattle (veterinarians performed R&T [V-R&T], herd personnel performed R&T [H-R&T], and veterinarians performed surgical repair via laparotomy [V-Surg]). RESULTS: Survival rates 14 days after LDA correction for the V-R&T, H-R&T, and V-Surg groups were 87% (286/329), 81% (327/403), and 85% (66/78), respectively. At 60 days after LDA correction, survival rates for the V-R&T, H-R&T, and V-Surg groups were 79% (260/329), 71% (286/403), and 73% (57/78), respectively. Multivariable analysis indicated that factors positively associated with failure to remain in the herd at 60 days after LDA correction included current mastitis status, history of a previous LDA, high preoperative risk, and correction of LDA by herd personnel rather than by a veterinarian. CONCLUSIONS AND CLINICAL RELEVANCE: Correction of LDA by veterinarians via an R&T procedure yielded results that were generally comparable to those for correction by veterinarians via laparotomy. Although survival rates at days 14 and 60 after surgery differed significantly between the V-R&T and H-R&T groups, herd personnel in this study used the R&T procedure to correct LDA and achieved survival rates within the range for those of practicing veterinarians.

Public health education at Michigan State University.

Many reports have highlighted the need for the veterinary profession to fill critical shortages of veterinarians in public health and food safety. Michigan State University's College of Veterinary Medicine offers educational programs within the professional veterinary curriculum, as well as graduate degree programs, to meet these societal needs. Within the scope of the professional veterinary curriculum, educational opportunities in public health include clerkships in veterinary public health and an innovative Web-based curriculum on judicious use of antimicrobials. For graduate degree programs, Michigan State University has a memorandum of understanding with the University of Minnesota for the Master of Public Health degree and an innovative Online Professional Master of Science in Food Safety degree program. A new option available is the opportunity for veterinary students to pursue the Master of Science in Food Safety concurrently with the DVM (DVM/MS in Food Safety). These educational programs will prepare graduates to meet societal needs in public health and food safety.