Technical note: Comparative evaluation of 3 methods for the quantification of nonesterified fatty acids in bovine plasma sampled prepartum.

Serum or plasma concentrations of nonesterified fatty acids (NEFA) are commonly used as biomarkers of lipolysis during the periparturient period in dairy cows. However, NEFA quantification usually requires sample submission to specialized diagnostic laboratories, at significant cost. Alternative methods for the measurement of NEFA concentrations are needed that decrease the cost per sample without compromising accuracy and precision. Our study compared the quantification of NEFA between the gold standard diagnostic laboratory method and 2 alternative methods: a 96-well plate protocol and a small-scale chemistry analyzer (CataChemWell-T; Catachem Inc., Oxford, CT). We used a total of 147 plasma samples collected from cows 7 to 13 d before their expected calving date (7 ± 3.3; mean ± SD days before actual calving) were used. We used linear and Passing-Bablok regression to identify systematic and proportional bias between the alternative methods and the gold standard. We also examined the level of agreement between each alternative method and the gold standard using Bland-Altman plots. We calculated the sensitivity and specificity of the alternative methods for detecting animals with excessive lipid mobilization prepartum (defined as NEFA concentration ≥0.30 mM by the gold standard test). We identified a constant difference between each of the alternative NEFA determination methods and the gold standard. Nevertheless, the mean bias was relatively small (-0.03 mM and -0.02 mM for the 96-well plate and small-scale analyzer methods, respectively). However, this tendency to underestimate NEFA concentrations had only a minimal effect on the ability of the tests to detect cows with excessive lipid mobilization prepartum (specificity 100%; sensitivity 88.9 and 94.4% for the 96-well plate and small-scale analyzer methods, respectively). The 96-well plate and small-scale chemistry analyzer methods tested in this study are suitable for the quantification of NEFA concentrations in plasma and the dichotomous classification of samples as indicators of excessive prepartum lipid mobilization.

Efficacy of oral administration of a modified-live Salmonella Dublin vaccine in calves.

OBJECTIVE: To determine the efficacy a modified-live Salmonella Dublin vaccine administered PO in an extralabel manner in the prevention of diseases associated with Salmonella Dublin infection. DESIGN: Randomized clinical trial. ANIMALS: 288 preweaned Holstein dairy calves on a commercial dairy farm. PROCEDURES: Calves were orally administered either 2 mL of a commercially available, modified-live Salmonella Dublin vaccine (n = 140) or a placebo (148) at 3 and 10 days of age. Signs of diarrhea and depression were recorded daily. Weight gain between 3 days of age and time of weaning was measured. Fecal samples from clinically depressed or diarrheic calves and fresh tissues samples from calves that died were submitted for bacterial culture of Salmonella organisms. RESULTS: Salmonella organisms were isolated from samples of 1.4% (2/140) and 3.4% (5/148) of calves receiving the vaccine and placebo, respectively. Additionally, 57.1% (80/140) and 60.1 % (89/148) of the vaccinated and control calves, respectively, had at least 1 day with an abnormal fecal score. Calves receiving the vaccine and placebo were not significantly different in terms of overall morbidity rate, Salmonella-specific morbidity rate, or average daily gain. Adverse reactions related to administration of the vaccine were not seen. The attenuated vaccine strain was not isolated from any fecal or tissue samples. CONCLUSIONS AND CLINICAL RELEVANCE: This method of vaccination was safe in young Holstein calves, although it was not effective in reducing the incidence of disease or improving weight gain on this farm. However, the power of this study was limited by a low incidence of clinical salmonellosis.

Cooperating with industry to teach food-animal medicine.

Cooperative programs with agribusiness offer opportunities for colleges of veterinary medicine to expand their instructional programs in agricultural practice. Agribusinesses associated with livestock agriculture recognize the importance of veterinary medicine in maintaining a vibrant and successful industry. Stewardship of corporate support involves close communication with advocates within the companies, providing them with documentation of the potential effects of corporate investments. This article describes the creation of the Michigan State University (MSU) Training Center for Dairy Professionals, a key aspect of which was the identification of innovative and productive areas of mutual interest and benefit. In addition to supporting the dairy industry by training veterinary students, the program offers specific benefits to investors, including the use of MSU facilities and direct participation in veterinary instruction.