A study was made of the effect on the S.N.F. percentage of milk of three types of rations, namely, heavy concentrates, heavy dry roughage and heavy succulent rations, when these were feel throughout the lactation period. The total digestible nutrients and the protein intakes of the three rations were in excess of the maintenance and production requirements of the cows in the groups. These nutrients were somewhat less in the case of the heavy dry roughage and heavy succulent rations than in the heavy concentrate ration.
The results obtained reveal that: (a) when a heavy concentrate ration was fed the S.N.F. percentage of the milk followed the ordinary trend with the advance of stage of lactation, (b) when heavy dry roughage and heavy succulent rations were given, there appears to have been a depressing effect on the S.N.F. percentage.
The milk production of the cows on the heavy concentrate ration did not drop as fast as the productions of those on the heavy dry roughage and heavy succulent rations. On the other hand the B.F. percentage of the cows on the former ration did not increase to the same extent as that of the cows on the latter two rations, but this was probably due to the slower decline in milk production of the former.