Hay versus silage: Does hay feeding positively affect milk composition?

This study provides a direct comparability between milk from cows fed hay or silage produced from the same parent plant material; the influence of feeding either hay or silage on amounts of various milk components was investigated. To give an overview regarding differences in milk composition, protein fractions, free amino acids, polyamines and biogenic amines as well as fatty acid profile and sensory properties were analysed. Moreover, the content of vitamin E and four different B-vitamins (B1, B2, B6 and B12) was determined. Results showed that there are some significant differences between hay milk and silo milk, especially regarding certain key nutrients. Linoleic acid, α-linolenic acid, lysine and putrescine showed higher concentrations in hay milk, while vitamin B12 and spermine were increased in silo milk. Sensory analysis showed that feeding of silage had a significant influence on colour (yellow), consistency and odour intensity, which were more pronounced in silo milk.