|Donahue, M - University Of Minnesota|
|Godden, S - University Of Minnesota|
|Bey, R - University Of Minnesota|
|Wells, S - University Of Minnesota|
|Fetrow, J - University Of Minnesota|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 9/30/2009
Publication Date: 12/4/2009
Citation: Donahue, M., Godden, S., Bey, R., Wells, S., Fetrow, J., Stabel, J.R. 2009. Effect of Feeding Heat-Treated Colostrum on Preweaning Health, Economics and Transmission of Mycobacterium avium subsp. paratuberculosis in Dairy Calves: Phase I [abstract]. Conference of Research Workers in Animal Diseases. p. 68.
Technical Abstract: Introduction and Objectives Colostrum provides protective immunoglobulins (Ig) and nutrients essential for calf health and performance. However, colostrum may also represent an early source of pathogen exposure including Mycobacterium avium subsp. paratuberculosis (MAP). Pilot studies have suggested that heat-treatment of colostrum at 60oC for 60 minutes may offer potential benefits to the calf including reduced pathogen exposure and improved passive absorption of colostral Ig.1 The objective of phase I of this study was to describe the effects of on-farm heat-treatment of colostrum on colostrum characteristics and calf health and performance. Materials and Methods The project enrolled calves from six commercial dairy farms in MN and WI during the summer of 2007. First milking colostrum was collected from fresh cows and refrigerated. Refrigerated colostrum was pooled daily or on alternate days to create unique batches of colostrum. One half of each unique batch was kept raw while the second half was heat-treated at 60oC for 60 minutes using a commercial on-farm batch pasteurizer (DairyTech, Inc. Windsor, CO). Samples of raw and heat-treated colostrum were frozen for bacteriological culture and IgG testing. Newborn heifer calves were removed from the dam before suckling and alternately assigned to be fed 3.8 L of either raw (n=523) or heat-treated (n=576) colostrum within two hours of birth. Blood was collected from calves between 1-8 days of age to determine serum IgG levels. Birth and weaning weights were recorded on three farms. All six farms recorded all treatment and death events occurring up to weaning. Preliminary Results Treatment did not affect colostrum IgG levels (heat-treated = 59.2 mg/ml; raw = 60.7 mg/ml, P = 0.42) but significantly reduced colostral microbial counts (logTotal Plate Count: heat-treated = 3.6; raw = 5.4, P < 0.0001). Calves fed heat-treated colostrum had significantly improved serum IgG levels (17.0 mg/ml) as compared to calves fed raw colostrum (14.5 mg/ml) (P < 0.0001). There was no effect of treatment on average daily gain or risk for treatment or death in the first 60 days of life (heat-treated: ADG = 1.4 lb/day, treated = 32.5%, died = 2.6%; raw: ADG = 1.4 lb/day, treated = 36.3%, died = 1.7%) (P > 0.05). Discussion and Conclusions On-farm pasteurization of colostrum reduced colostral bacterial exposure and was associated with enhanced passive absorption of colostral Ig in calves. However, under these study conditions there was no effect of treatment on rate of gain or health in the preweaning period. Explanations for this lack of effect may include low baseline levels of disease on study farms or perhaps other unmeasured factors related to the feeding of heat-treated colostrum. In Phase II of this study animals will be followed into adulthood to describe the effect of treatment on longevity, milk production and risk for infection with MAP during the first three lactations. Acknowledgements The investigators wish to thank the six participating dairy farms plus study technicians Eb Ballinger and Amber Hazel. 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 treated colostrum on passive transfer of immune and nutritional parameters in dairy calves. J. Dairy Sci. 90: 5189-5198.