Effects of Adding Concentrates to Ad Libitum Roughage Feeding in the Dry Period

Two experiments were conducted to compare feeding dry cows for 6 wk before calving ad lib. roughage alone or ad lib. roughage plus 8 lb of concentrates daily. In one experiment, an equal amount of extra concentrates had been fed in the last part of the preliminary lactation to the cows not fed concentrates during the dry period. The cows used were paired on the basis of their previous lactation. A total of 75 pairs of cows was used in the two experiments. Feeding extra concentrates during the dry period caused a highly significant increase of 302 lb of FCM in the first ]5 wk of the next lactation. Extra concentrates fed during the last of the lactation did not change body condition before calving and did not stimulate lactation after calving. Cows fed concentrates in the dry period gained 30.5 lb more in 35 days than pair-mates not fed grain. They also lost 20.3 lb more in 35 days after calving. These differences in weight change were highly significnt. It is postulated that providing extra nutrients to the prepartum dry cow stimulates metabolism, resulting in high initial lactation levels, and that the high lactation level is partly mainrained at the expense of the accumulated reserve body tissue.