Performing Department
Animal Dairy & Veterinary Sciences
Non Technical Summary
Automated milk microbiology testing will be further validated for newly described bacteria isolated from dairy cow milk samples. Clinical pathology testing will help to develop a simple, practical calf blood test panel to help reduce death loss in pre-weaned dairy calves. A milk preservative will be evaluated for possible effectiveness in reducing bacteria counts for a longer period of time after calf milk is pasteurized, making it safe to feed calves for a greater amount of time before it must be discarded or re-pasteurized.
Animal Health Component
100%
Research Effort Categories
Basic
35%
Applied
65%
Developmental
(N/A)
Goals / Objectives
Validation of clinical significance of novel milk culture isolates identified using MALDI-TOF. Clinical pathology testing of dairy calves. Study different concentrations of sodium percarbonate in colostrum and milk for their effects on bacteria counts over time under the conditions which exist when those products are fed to dairy calves.
Project Methods
Of the > 70,000 milk samples cultured per year, those with unusual mastitis isolates will be traced back to cows of origin. Means and medians of continuous variables such as age-season-and-fat corrected milk production (305ME), daily milk production, SCC, etc. will be calculated for each pathogen isolated from milk. Clinical mastitis will be recorded electronically, and evaluated as a proportion of the cases of each pathogen isolated. Continuous and categorical outcomes will be analyzed with the appropriate statistical tests.We have access to the data from a calf farm that raises 6,000 dairy calves per year. We will focus on calves during the first 60 days of life, until weaning age when mortality plummets relative to the first two months of life. The Chemwell T® clinical pathology analyzer that we have validated and used for 7 years will be the utilized. At first, we will test both whole blood and serum - different tests require one sample or the other - from the calves for a large panel of blood tests and parameters including cell counts, minerals, and enzymes. All sample collection procedures will be performed under the supervision of a veterinarian in accordance with an animal welfare audit that the calf farm participates in annually. No one from USU will collect any of the blood samples. 200 calves with signs of disease will be tested in order of their contracting the diseases. Diarrhea, coughing, nasal discharge, head tilt, off feed, weakness, or recumbency are recorded and entered into DC305 electronic records. Treatments, duration of treatments, and recovery or death are also recorded. Tests including CBC, Diff, glucose, packed cell volume (PCV), Na, K, Cl, pCO2, base excess, anion gap, pH, BUN, Cr, creatine kinase (CK), and others will be performed on all 200 initial study calves with disease signs. 200 calves with no signs of disease will also be tested at 1-12, 13-24, 25-36, 37-48, and 49-60 days of age, with 40 calves tested within each age range. After we evaluate the prognostic and treatment guidance value of the various test results, we will "distill down" to the most practical and meaningful panel of tests for prognosis and treatment of sick dairy calves.Sodium percarbonate milk preservative will first be studied in bacteria-spiked milk samples. Known concentrations of E. coli bacteria will be added to sterile milk, with the concentrations then verified by their numbers within the total standard plate count (SPC). Five doses (concentrations) of sodium percarbonate will be studied, and SPC will be measured after 1, 2, 3, 4, 5, 6, 7, 8 and 24 hr of incubation. Based on our previous work, the milk samples will be incubated indoors at 37° C (8). After this preliminary work, 3 doses (concentrations) of sodium percarbonate will be studied in buckets of raw milk that mimic the conditions under which it is fed to calves. SPC will be transformed to the log of SPC for analyses, and then reverse-transformed to raw SPC for descriptive statistics. Analysis of variance (ANOVA), and if significant differences were indicated, Tukey's multiple comparison test will be used to evaluate differences in means of the continuous outcome variable SPC among the ordinal categories of sodium percarbonate (treatment) dose.