the availability of net energy in the milk of aberdeen angus primiparous cows and his relationship with the calves performance was studied. fourty seven cows, raised under a range condition, in aceguá. rs county, were evaluated between september 2005 to april 2006. milk production (pl) was estimated by before and after suckle method, from birth to weaning (189days), every 21 days. effects studied were pregnancy (g), and milk production level (npl): npla <1035.70 ± 36.65 kg
