The effects of feeding fodder beet with two levels of concentrate allocation to dairy cattle

Twelve cows were used in a cyclic changeover design experiment to examine the effects of feeding fodder beet (variety Kyros) at three levels (0, 2 and 4 kg dry matter (DM) d^?1) with two levels of concentrate feeding (4 and 8 kg DM^?1). Silage was offered ad libitum. At the start of the experiment the mean number of days after calving was 46 and the mean live weight 516 kg. The experiment consisted of four 3-week periods with intake and performance measurements during the last week of each period. An in vitro analysis of the feeds for the silage, fodder beet and concentrate respectively was: DM (g kg-^?1) 189, 163, 860; crude protein (g kg DM^?1) 143,76,201; metabolizable energy (MJ kg DM^?1) 104, 133, 13–5. Silage DM intake decreased but total DM intake increased when fodder beet was fed. The DM intakes (kg d^?1) for treatments (fodder beet/ concentrate) 0/4, 2/4, 4/4, 0/8, 2/8, 4/8 respectively were: silage DM 91, 79, 78, 83, 70 and 68 (s.e.d. =0.31); and total DM 130, 138, 156, 162, 166, 183 (s.e.d. = 0.36). Feeding fodder beet had no significant effects on milk yield or milk composition, but there was a significant increase in milk protein yield when fodder beet was included in the ration. There were no significant interactions between level of fodder beet feeding and concentrate level. Increasing the level of concentrate feeding led to a highly significant increase in milk yield, milk protein content and yield of milk constituents. The yields for treatments 0/4, 2/4,4/4,0/8, 2/8,4/8 respectively were: milk yield (kg d^?1) 206, 204,21 8, 241,235, 244 (s.e.d. = 0–58); fat yield (g d^?1) 827, 793, 885, 954, 936, 954 (s.e.d. = 394); and protein yield (g d^?1) 622, 628, 679, 774, 777, 814 (s.e.d. = 179). There were no significant differences in milk yield and milk composition when fodder beet was included in the diet which may have been due to the low crude protein content of the diet.