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The objectives of this study were to perform an in-lab validation of the Minnesota Easy Culture System II bi-plate method as compared to standardized laboratory culture methods and to describe inter-reader agreement for bi-plate culture results., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2006

The objectives of this study were to perform an in-lab validation of the Minnesota Easy Culture System II tri-plate method as compared to standardized laboratory culture methods and to describe inter-reader agreement for tri-plate culture results., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2006

Bovine viral diarrhea virus (BVDV) is commonly found in cattle and causes significant economic losses. Despite long term and widespread use of commercial modified live vaccines, BVD remains problematic. BVDV are classified into two genotypes, BVDV-1 and BVDV-2, and are further subdivided within the genotype by sequence analysis. Most genetic analysis is performed on the 5'-untranslated region of the genome as it is relatively conserved, however, this region does not code for an antigen. The objective of this study was to characterize recent BVDV field isolates using genetic analysis of the E2 gene in combination with antigenic methods using antisera generated against multiple isolates in a high throughput serum neutralization assay., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2010

Early studies have suggested that bacteria in colostrum may interfere with passive absorption of immunoglobulins (lg) in newborn calves (James et al, 1981), and recent studies reported that calves fed pasteurized colostrum had improved passive transfer of IgG versus calves fed fresh colostrum (Johnson et al, 2007; Heinrichs et al, 2009a). However, a recent study reported that colostrum bacteria counts were not associated with IgG absorption (Heinrichs et al, 2009b). Do pathogenic or non-pathogenic bacteria, living or dead, truly interfere with lg absorption? Bovamine® (Nutrition Physiology Company, LLC, Overland Park, KS) is a direct-fed microbial (DFM or probiotic) containing a patented combination of living Lactobacillus acidophilus ( 1 x 109 cfu/1 g dose) and Propionibacterium freudenreichii (2 x 109 cfu/1 g dose). The study objective was to describe the effect of supplementing colostrum with living or dead DFM on serum total protein (STP) and IgG levels, and apparent efficiency of absorption of IgG (AEA %)., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2010

Lago et al (2008) reported that the adoption of an on-farm culture (OFC) system to guide strategic treatment decisions resulted in a reduction in antibiotic use, but no decrease in bacteriological cure risk for mild or moderate cases of clinical mastitis (CM). The objective of this abstract is to describe the effect of the aforementioned treatment program on other short and long term outcomes after CM., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2009

This study aimed to investigate the efficacy of using the California Mastitis Test (CMT) alone, or the CMT and on-farm culture (OFC) in series, to diagnose and treat subclinical mastitis after calving., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2009

Bovine mastitis is caused by a variety of pathogens, and treatment of bovine mastitis accounts for the greatest usage of antimicrobials on dairy farms. The possibility of increased resistance caused by usage of antimicrobials for treatment of bovine mastitis is a potential concern for veterinarians. The objective was to describe antimicrobial resistance of gram-positive mastitis pathogens isolated from cases of bovine mastitis., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2009

A controlled trial was conducted in 16 commercial dairy herds to describe the effect of an alkalinizing (A) and an acidifying (B) bedding conditioner on bedding pH and bacterial counts when applied twice per week to stalls containing shavings (SH), digested manure solids (DS) or recycled sand (RS) bedding materials. Bedding pH and bacterial counts were measured in samples collected one day, and again in three to four days, after new conditioner was applied to the stalls. Conditioners A and B had an alkalinizing and acidifying effect, respectively, on bedding pH. Although conditioner A reduced coliform bacterial counts by between 0.7 and 1.6 logs in RS and DS bedding for one day and it had no effect on Klebsiella spp. or Streptococcus spp. bacterial counts in these bedding materials. Activity against coliform bacterial counts did not persist for three to four days. Conditioner A reduced bacterial counts in SH by between 0.3 to 1.3 logs for at least one day, but had no persistent activity for three to four days when stalls were rebedded. Conditioner B did not reduce bacterial counts in either DS or RS bedding, and actually increased Klebsiella spp. bacterial counts in DS. However, conditioner B reduced bacterial counts in SH for one day (0.4 to 1.8 log reduction, depending on the bacteria group), with antibacterial activity persisting for three to four days post-application (0.4 to 0.6 log reduction), even though stalls had been rebedded in the interval between conditioner application and collection of the day 3 to 4 bedding samples. For all bedding materials studied, bacterial counts were significantly lower in stalls for which fresh bedding had been added within the previous 24-48 hours. The magnitude of reduction in bacterial counts associated with having recently bedded stalls (approximately 1.6, 0.6, and 1.6 log reduction in coliform, Klebsiella spp., and Streptococcus spp. bacteria, respectively) was, on average, greater than the magnitude of reduction in bacterial counts attributed to the bedding conditioner treatments being studied. These findings suggest that the alkalinizing conditioner A will not be useful on commercial dairies, regardless of bedding type in use, if applied only twice per week in accordance with manufacturer recommendations. The acidifying conditioner B will not be useful on commercial dairies using DS or RS bedding, but may be useful to reduce bacterial counts in SH bedding. Finally, findings suggest that producers can significantly reduce bacterial exposure to teat ends simply by applying fresh bedding to stalls on a more frequent basis., The Bovine Practitioner, Vol. 43, No. 1 (2009 Spring)

The importance of timing, volume and quality of colostrum fed has long been understood, but the improvement of colostrum quality via on farm heat-treatment is a concept developed only within the last few years. Bacterial contamination of colostrum is not only a potential source of pathogen exposure, but perhaps interferes with the absorption of lg. An earlier pilot study in 49 calves on one farm indicated that feeding heat-treated colostrum enhanced the efficiency of absorption of colostral IgG in the neonatal calf, presumably by reduction in bacteria counts in colostrum. A larger controlled study in six large commercial dairies was undertaken to determine if the pilot study results could be replicated. The objective of this study was to determine if calves fed raw versus heat-treated colostrum differed significantly in serum total solids and serum IgG concentrations., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2008

Mastitis remains the most costly infectious disease, and the most frequent cause of antibacterial use on commercial dairy farms. As such, research should continue on the development and validation of new management tools that will help reduce the health and economic impact of this disease, while at the same time promoting the judicious and strategic use of antimicrobials on dairy farms. The adoption of on-farm culture systems may allow producers to make more strategic mastitis treatment decisions, potentially reducing antimicrobial use while maintaining the future production potential of the cow. The objective of this study was to describe the effect of using an on-farm culture system to guide strategic treatment of clinical mastitis cases on intramammary antibiotic use and bacteriological cure rates in affected quarters., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2008

The dairy industry recognizes the necessity of providing adequate colostrum to newborn calves to obtain passive immunity. This aids in lowering the rate of disease and death amongst young calves. Bacteria in colostrum can interfere with the immunoglobulin G (IgG) absorption in newborn calves, potentially resulting in failure of passive transfer. Industry recommendations currently suggest bacteria levels in colostrum be, American Association of Bovine Practitioners Proceedings of the Annual Conference, 2008

Colostrum is the single most important management factor determining calf health and survival. Calves experiencing successful passive transfer of colostral immunoglobulins (serum IgG > 10.0 mg/ml) have improved preweaning health and survival, improved growth rate and feed efficiency, reduced age at onset of puberty, reduced age at first calving, and improved first and second lactation milk production. Unfortunately, many producers continue to suffer significant losses related to poor colostrum management. Factors affecting the success of a colostrum management program include 1) Quality of colostrum fed, 2) quantity of colostrum fed, 3) quickness of providing the first colostrum feeding and 4) cleanliness of colostrum (i.e. bacterial contamination). Use of commercial colostrum replacement products may offer multiple advantages, including consistent quality, convenience, and cleanliness. However, it is important to evaluate the ability of commercially available colostrum replacement (CR) products to achieve successful passive transfer of immunoglobulin G (lgG) in calves managed under field conditions. The objective of this study was to describe passive transfer of lgG in newborn calves fed one or two doses ( 100 gm IgG or 200 g IgG) of a commercial colostrum-derived colostrum replacement (CR: Land O'Lakes Colostrum Replacement®, Land O'Lakes Animal Milk Products, St. Paul, MN) or 4 quarts of maternal colostrum (MC)., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2007

Identifying and eliminating subclinical intramammary infections (IMI) present at the time of calving could result in milk quality, cow health and production benefits throughout the future lactation. A multi-site, multi-herd, controlled field study aims to validate the efficacy, and to quantify the cost-benefit of incorporating on-farm culture systems into both clinical and subclinical mastitis monitoring and treatment programs. The objective of this manuscript is to present preliminary results describing the prevalence, etiology and self cure rates of subclinical IMI in fresh cows and quarters., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2007

The objective of this study was to determine the effect of a metaphylactic prepartum intramammary infusion of 200 mg cephapirin sodium (Cefa-Lak®) per quarter in heifers and mature dairy cows. Treated and control animals from a large, well-managed herd were evaluated for selected production parameters during the immediate post calving period., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2005

Calves with failure of passive transfer are much more susceptible to disease and death than calves with adequate colostral immunoglobulin G (lgG) absorption. Although colostrum is vital to calf health, it can also serve as a vector for pathogens such as Salmonella spp, Listeria monocytogenes, Escherichia coli, Mycoplasma bovis, and Mycobacterium avium subsp. paratuberculosis (MAP), the causative agent of Johne's disease. While batch pasteurization at traditional times and temperatures (145°F [63°C] for 30 minutes) will kill pathogens in colostrum, it destroys significant amounts of lgG. Our objective was to determine if we could use a lower temperature/longer time approach to kill pathogens while still preserving IgG content and activity., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2005

Results of two large national studies indicate that the national preweaning mortality rate in dairy heifers has improved very little over the past ten years (10.8% in National Animal health Monitoring Systems (NAHMS), 1993, 8. 7% in NAHMS, 2002). Failure to reduce mortality in preweaned dairy heifers is partially attributable to poor colostrum management practices. In 1993 (NAHMS), 41 % of 2177 calves sampled between 24 and 48 hrs of age suffered from failure of passive transfer (FPT), or low serum immunoglobulin G (IgG) concentrations. Numerous studies have demonstrated that failure of passive transfer (FPT; calf serum IgG concentration< 10 mg/ml) is associated with a significant increase in risk for morbidity and mortality in the period between birth and weaning (Fowler, 1999; Wells et al, 1996). Conventional factors considered to be important in an effective colostrum management program have included quantity of colostrum fed, quality of colostrum fed (IgG concentration) and quickness (or age at first feeding). Offering a second feeding of colostrum is also frequently recommended. Recently, calf management experts have also begun to evaluate colostrum cleanliness (total bacteria count or total coliform count) as another potentially important factor. Limited studies have suggested that bacteria counts in colostrum not only serve as a pathogen source, but may also reduce efficiency oflgG absorption in the gut. The objective of the current study was to evaluate the relationship between serum IgG concentrations in dairy calves and the aforementioned colostrum management factors (colostrum quantity, quality, quickness, cleanliness)., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2004

Johne's disease (JD) is a chronic and progressive intestinal disease in ruminants caused by Mycobacterium avium subspecies paratuberculosis (Map). The usual route of infection is fecal-oral. The disease manifests in adult cows and results in economic losses. Although Map does not propagate in the environment, it survives for long periods in different environmental conditions expected on many dairy farms. Johne's disease control programs have been developed in different countries and in several US states with a goal to test and classify herds of cattle as infected or presumptively noninfected with maximum accuracy and least cost. Generally, these programs utilize recognized laboratory tests such as ELISA or direct microbiological individual fecal culture. However, these tests have several disadvantages, especially when applied in herds with subclinical disease or low prevalence. Since Map is shed into the environment by dairy cattle through fecal contamination and appears to survive well, a better understanding of Map distribution in the environment could lead to improved herd-screening alternatives. Objectives of the study were: 1) to describe Map distribution and prevalence in the environment on Minnesota dairy farms, and 2) to assess the relationship between culture status of Map in the farm environment and fecal-pooled culture status on dairy farms., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2004

The practice of blanket dry cow antibiotic therapy has been very successful in eliminating many existing infections at dry-off and in preventing new intramammary infections (IMI) during the dry period. However, many new intramammary infections still occur during the dry period due to factors such as delays in keratin plug formation, poor sensitivity of some invading pathogens to intramammary antibiotic preparations, and decreases in antibiotic concentrations near the end of the dry period. The primary objective of this study was to describe whether quarters treated with an internal teat sealant in addition to an antibiotic (treated) at dry-off would develop fewer new intramammary infections during the dry period and early lactation, as compared to quarters treated with antibiotic alone (control). Secondary objectives were to describe the effect of treatment on the prevalence of intramammary infection after calving, the incidence of clinical mastitis events between dry-off and 60 days in milk (DIM), and linear score (LS) after calving., American Association of Bovine Practitioners Proceedings of the Annual Conference, 2003

The objectives of this study were to determine inter-reader agreement and to describe the accuracy of the Azotest® strip for estimating urea nitrogen concentrations in milk samples from individual cows (n = 214), milk lines (n = 41) and bulk tanks (n = 41). Samples were split, with one portion used for milk urea nitrogen (MUN) analysis using the Azotest® strip, and the second portion submitted to an accredited diagnostic laboratory for MUN analysis using wet chemistry analysis as the gold standard test. There was excellent inter-reader agreement (Kappa = 0.87) in this study for distinguishing between individual cow samples with either normal or high MUN values. However, the overall accuracy of the Azotest® strip was poor, with MUN results from the Azotest® strip being different than those from wet chemistry analysis (P < 0.01). There was poor agreement between the two test methods (Kappa = 0.12 - 0.14); average Azotest® results were approximately 5 mg/dl units higher than the wet chemistry analysis method for either individual cow, milk line or bulk tank samples. Forty-five percent of individual cow samples, and 45% of milk line and bulk tank samples were correctly categorized as low, normal or high. The sensitivity and specificity of the Azotest® strip for detecting high MUN concentrations (vs normal or low) in individual cow samples was 98.7 and 33.1%, respectively, and in pooled milk line and bulk tank samples was 100 and 21.1%, respectively. For this data set, the predictive value of a positive test result when looking for high MUN measures (vs normal or low) was only 33.1 to 35.7%. Thus, approximately two-thirds of samples identified as high by the test strip actually had a normal MUN concentration. The sensitivity and specificity of the Azotest® strip for detecting low MUN concentrations (vs normal or high) in individual cow samples was 0 and 100%, respectively. The test failed to correctly identify any truly low MUN samples as being low, and overestimated the MUN concentration in a high proportion of truly low and normal samples. Given this high degree of test inaccuracy in these data, we conclude that the Azotest® strip will not be beneficial to commercial dairy producers or dairy consultants. The authors recommend that producers wishing to monitor MUN submit milk samples to an accredited diagnostic laboratory for MUN analysis., The Bovine Practitioner, Vol. 37, No. 1 (2003 February)

SummaryGabexate mesilate (GM), a synthetic serine protease inhibitor with a short half-life time of approx. 80 sec, was applied as the exclusive anticoagulant in small scale extracorporeal circulation in narcotized dogs and sheep. The animals underwent a veno-venous bypass. As the blood was drawn out of the femoral vein, GM was infused immediately into the extracorporeal system. GM was greatly reduced because of its short half-life time before the blood reentered the animal via a brachial vein. In order to control the coagulatory state of the blood, the Activated Clotting Time (ACT), Partial Thromboplastine Time (PTT) and Recalcification Time (RT) were measured in regular intervals. In addition, a screen pressure test device was used to monitor on line during ECC the tendency of blood clotting. It was shown that the blood of the extracorporeal system was sufficiently anticoagulated by an infusion of 0.03 mg/ml/min GM. During two hours ECC, simultaneously measured ACT - values of the animals only differed up to 10 percent from the native values. Pilot studies have shown that the results of these model investigations could be successfully transferred to extracorporeal circulation with membrane oxygenators and pumps as they are clinically used.

Extracorporeal CO2-removal promises to be an efficient alternative to the conservative treatment of advanced lung diseases. Extracorporeal CO2-removal is achieved in a veno-venous bypass in combination with low frequency ventilation. Positive clinical results in the treatment of adult respiratory distress syndrome (ARDS) are encouraging. In order to prove the applicability of this method to different kinds of respiratory insufficiency, physiological studies using animal models are necessary. We report here on experiments with dogs and sheep undergoing a veno-venous bypass employing a CO2-eliminator. The experimental results are compared with theoretical values which predict the important relationships between blood flow rate of the extracorporeal circulation (ECC), the CO2-elimination capacity of the CO2-eliminator and the low ventilation rate (down to apnea for 5 h) of the natural lung. It was shown that the blood gas data as well as acid base status could be maintained within physiological ranges.