the cows were all crossbred animals all in their second to fourth lactation and at 100-120 d of lactation when the experiment began. the animals were balanced for these factors across the two groups, and account was also taken of their average live weight of 450 kg and previous milk production. all cows also had individual acces adlibitum to fresh Leucaena leucocephala supplementation at milking times. A pre-experimental period of l wk was allowed on the experimental area and indoor feeding for the animals to adapt to their changed management conditions and for preliminary milk production data to be collected.