Hardly any differences in the composition of milk from cows fed with or without silage

In order to study eventual differences in the composition of milk from cows fed with or without silage bulk tank samples (2 milkings) were analysed for different milk components. During the winter period 18 commercial dairy farms with or without silage feeding and during the summer period 8 and 6 farms, respectively, were sampled. All farms had comparable production conditions (e.g. same region, similar husbandry conditions and milk production levels). There was no significant difference of the gross milk composition between the silage an non silage groups.In both periods concentrations of conjugated linoleic acids (CLA) and omega-3 fatty acids were slightly lower in milk from cows fed with silage. Milk from farms feeding silage had slightly higher concentrations of saturated fatty acids and lower concentrations of unsaturated fatty acids. In addition, milk fat from these farms tended to be more susceptible to fat damage.Vitamin and mineral contents were nearly identical for both groups and no sensory differences could be found. During the winter period Clostridium tyrobutyricum spore counts were significantly higher in milk from farms feeding silage.