Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/15/2008
Publication Date: 9/25/2008
Citation: Donahue, M., Godden, S., Bey, R., Wells, S., Fetrow, J., Stabel, J.R. 2008. Effect of Feeding Raw Versus Heat-treated Colostrum on Passive Transfer of Immunoglobulin G in Newborn Dairy Calves [abstract]. The American Association of Bovine Practitioners.
Technical Abstract: Introduction 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 Ig. 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 (Johnson et al., 2007). 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. Materials and Methods Six commercial dairy farms in Wisconsin and Minnesota, ranging from 1,200 to 1,600 cows, were enrolled into the study between June and August, 2007. First milking colostrum was collected from fresh cows and refrigerated. Daily or every other day the refrigerated colostrum was pooled to create a new batch, mixed, and then split into two equal portions. One half of each batch of colostrum was kept raw, while the other half was heat-treated at 60 degrees C for 60 minutes using a commercial on farm batch pasteurizer (DairyTech, Inc., Windsor, CO). After processing, duplicate 50 mL samples of both raw and heat-treated colostrum were collected into sterile vials, labeled, dated and frozen. The processed colostrum (raw or heat-treated) was then stored in 3.8 L portions in clean, sanitized, and labeled bottles and refrigerated for subsequent feedings to newborn calves. Newborn calves (n = 1102) enrolled into the study were removed from the dam within one hour of birth and alternately assigned to be fed 3.8 L of either raw or heat-treated colostrum. All colostrum was fed within two hours of birth. Records for calves included calf ID, birthdate, birth time, the type of colostrum fed (raw or heat-treated) and the individual batch of colostrum fed. Calves were then housed individually in barns or hutches. Calf treatment and mortality events occurring between birth and weaning were recorded. Research technicians visited each farm weekly to collect blood samples for previously enrolled calves between the ages of 24 hours and eight days of age. Colostrum samples later underwent laboratory culture to determine microbial total plate count (TPC) and total coliform count (TCC) cultures (cfu/ml), and laboratory determination of colostrum IgG concentrations (mg/ml) using turbidometric immunoassay (TIA). Blood was allowed to clot and the serum collected. Serum total solids concentration (TS, g/dl) was analyzed using a hand-held refractometer. The serum sample was then subsequently split and frozen in paired aliquots. One of these aliquots was later analyzed for serum IgG concentration (mg/ml). Results Preliminary results of mean serum TS concentrations were significantly greater for calves fed heat-treated colostrum (5.83 g/dl) vs. calves fed raw colostrum (5.70 g/dl) (p < 0.001). Similarly, the mean serum IgG concentration was significantly greater for calves fed heat-treated colostrum (16.97 mg/ml) vs. calves fed raw colostrum (14.48 mg/ml) (p < 0.001). Significance Improved serum IgG concentrations in calves fed heat-treated colostrum is thought to be due to reduced bacterial interference with IgG absorption in the gut. Analysis is pending to describe colostrum IgG concentrations (mg/ml), TPC (cfu/ml) and TCC (cfu/ml). Acknowledgements This project was funded by USDA-CSREES. Reference Johnson, J., S. Godden, T. Molitor, T. Ames, and D. Hagman. 2007. The effect of feeding heat tr