Fodder beets in complement of grass silage for dairy cows

Abstract

In four trials (2 at the beginning of the lactation and 2 during mid-lactation) fodder beets were fed to dairy cows with grass silage given ad libitum. Supply of beets was between 0 and 4 kg DM per day per animal. In the two first trials DM content of beets was 12 % versus 21 % in the two other trials. Fodder beets with low DM decrease silage intake notably and their « fill value » is about 1, which is high for this type of food. On the other hand beets with high DM have a fill value of about 0,5, similar to that of concentrates. When animals received beets their milk production decreased slightly (0,23 kg/day), but, at the same time protein content of the milk increased 0,85 point and fat content 1,23 point. In our experimental conditions, taking in account the ash content of the beets and the digestive interactions due to their concentrate nature dietary energy values with beets is correct and similar to that predicted for the value of feed.