Rapeseed mustard cake (RMC) can be readily used as a protein supplement in lactating cows diet due to its availability and being cheaper than other oil cakes. The use of RMC as protein supplement is constrained due to its higher level of glucosinolates that have variable adverse effect on palatability, intake, nutrient utilization, thyroid hormone status and overall performance of the animals. The new improved varieties of rapeseed mustard cultivar which is low in both erucic acid (