Experiments were carried out to develop a reliable and practicable method for estimating rate of milk secretion of beef cattle in the field. After preliminary studies a 6-hr, test was adopted; 20 I. U. of oxytocin were given intravenously at the beginning and end of the test period and milk was obtained: by teat cannulation. The method was evaluated under field conditions. Milk yield, fat percentage and energy production were estimated over a lactation period for a herd of 62 Hereford cows. It was concluded that the method could have a wide application in studies of beef cattle husbandry and also would be a useful technique in studies of productivity of animals on pasture.