FEEDING OF BRONOWSKI, SPAN AND COMMERCIAL RAPESEED MEALS WITH OR WITHOUT ADDITION OF MOLASSES OR FLAVOR IN RATIONS OF LACTATING COWS

Lactating Holstein dairy cows rvere used in two experiments to determine if using Bronowski (low glucosinolate) rapeseed meal (RSM) in place of commercial RSM (high glucosinolate) would allow greater quantities of RSM to be used in dairy rations without adverscly atfccting animal performance. A third experiment was carried out to determine the effect of pelleting and adding either molasses or "feed flavor" on consumption of a dairy ration containing l97c commercial RSM or l97c Span RSM with no additives. Whcn commcrcial RSM made up 14% of the grain mixture (11.9% including hay), grain consumption was reduced (P 0.05) on level of milk production. When Bronowski made up 10, l7 or 24vr: of the grain mixturc in place of soybean meal (SBM), fced intake, milk eomposititrn. digestibility of the ration and nitrogen retention were not different (P>0.05). The addition of 19% commercial or Span RSM in place of SBM reduced ad libituni grain consumption but not significantly fP>0.05). Pelleting or addition of molasses or "feed flavor" did not fP>0 05) improve ad libitum intake of rations containing commercial RSM. However, the trend was for greater consunption. Daily milk yield was higher (P<0.05) fbr SBM. flavored feed and Span RSM treatments compared to the commercial RSM treatment. Thc low fat test fP<0.0-5) observed for the SBM and pellctcd RSM rations could be due to lower fibre level in the first case and a pelleting effect in the second case. Dcux essais ont 616 conduits sur des vaches Holstein en lactation pour ddterminer si I'cmploi du tourteau de colza Bronowski (faiblc tcneur cn glucosinolate) au lieu de