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United States Department of Agriculture

Agricultural Research Service

Research Project: INTERVENTIONS TO REDUCE FOODBORNE PATHOGENS IN SWINE AND CATTLE

Location: Food and Feed Safety Research

Title: Development of colonic microflora as assessed by pyrosequencing in dairy calves fed waste milk

Authors
item Edrington, Thomas
item Dowd, Scot -
item Farrow, Russel -
item Hagevoort, G -
item Callaway, Todd
item Anderson, Robin
item Nisbet, David

Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 4, 2012
Publication Date: July 30, 2012
Repository URL: http://handle.nal.usda.gov/10113/57308
Citation: Edrington, T.S., Dowd, S.E., Farrow, R.F., Hagevoort, G.R., Callaway, T.R., Anderson, R.C., Nisbet, D.J. 2012. Development of colonic microflora as assessed by pyrosequencing in dairy calves fed waste milk. Journal of Dairy Science. 95:4519-4525.

Interpretive Summary: Dairy farms often use milk from sick cows, or from those that have just given birth, to feed young calves. In an effort to make the milk healthier for the calves, some producers pasteurize this waste milk prior to feeding. This practice, while eliminating harmful pathogens such as Salmonella, may also kill beneficial bacteria that would aid in gut maturation of the calf. To evaluate the effects of feeding pasteurized waste milk on calf microflora, we collected fecal samples from calves fed either pasteurized or non-pasteurized waste milk at multiple ages up to 6 months of age. The fecal samples were examined for bacterial diversity using a pyrosequencing technique. In general, bacterial diversity as represented by the total number of different species was greater for the calves fed pasteurized waste milk at all ages (except 1 week of age) and increased with increasing age in both treatments. Salmonella were detected in 9 out of 14 (64%) of the week-old calves fed non-pasteurized milk but not in any fed pasteurized waste milk. Certain types of bacteria that are important in the rumen of cattle were more prevalent in the pasteurized animals and became significantly higher in the older animals from this group. The consistent detection of Salmonella in the younger animals fed non-pasteurized milk and its absence in all other groups is an important finding related to this feeding practice. This study clearly shows that pasteurization of waste milk prior to feeding to young calves is an appropriate and even beneficial practice.

Technical Abstract: The objective of the current study was to examine the effect of pasteurization of waste milk used to feed dairy calves on the bacterial diversity of their lower gut. Using 16S rDNA bacterial tag-encoded FLX amplicon pyrosequencing (bTEFAP), fecal samples from dairy calves aging from 1 week to 6 months old and fed either pasteurized or non-pasteurized waste milk were analyzed for bacterial diversity. Calves were maintained on two separate farms and aside from how the waste milk was treated, were housed and cared for similarly. Fifteen calves were sampled from each age group (1, 2, and 4 weeks, and 2, 4, and 6 months of age; n = 90 samples per milk treatment, 180 total samples) on each farm via rectal palpation and the samples shipped and frozen prior to analysis. In general, bacterial diversity as represented by the total number of different species was greater for the calves fed pasteurized waste milk at all ages (except 1 week of age) and increased with increasing age in both treatments. Proteobacteria, Bacteroidetes, and Firmicutes were the predominant phyla. Differences in phyla and class were observed among treatments and age of calf but with no consistent trends. Salmonella were detected in 9 out of 14 (64%) of the week-old calves fed non-pasteurized milk. Treponema, an important beneficial bacteria in cattle rumen, was more prevalent in the pasteurized animals and became higher (P < 0.001) in the older animals from this group. Escherichia-Shigella were detected among treatments at all ages and highest at one week of age, averaging approximately 21 and 20% of all bacteria for calves fed pasteurized and non-pasteurized waste milk, respectively and declining as calves aged (2.6 and 1.3%). The consistent detection of Salmonella in the younger animals fed non-pasteurized milk and its absence in all other groups is an important finding related to this feeding practice.

Last Modified: 4/17/2014