FIG 3.

Vitamin B₁₂ concentrations in rumen, fecal, plasma, and milk samples. To facilitate analysis of the microbiota, the samples for each site were categorized as having high, medium, or low concentrations of vitamin B₁₂ relative to other samples, so that each category contained approximately 33% of the samples. The total milk category is the yield of vitamin B₁₂ produced by the animal on the day of sampling, this number was calculated by multiplying the concentration by the volume of milk produced on the day of measurement.