Evaluation and Observation of Testing Feed Efficiency in Angus Seedstock Heifers

A total of 38 Angus heifers in four contemporary groups over two years were evaluated for pelleted feed intakes, feed conversions and residual feed intake (RFI) using a PinPointer feeding system at Wardens Farms, Council Bluffs, Iowa. Daily pellet intakes (.47 mcal/lb of NEg) averaged 18.6 lbs during the first week and peaked at week nine with 26 lbs. Individual heifer variation on a percent of body weight basis was from 2.1% to 3.3%, but during week 2 the range was 1.7%. Adjusted feed conversions calculated using BIF guidelines averaged 8.11 and 13.24 for 2005 and 2006, respectively. RFIs by methodology averaged zero, but had a standard deviation of 1.24 and 1.18 for both years, respectively, which is similar to evaluations looking at bulls for efficiency. RFIs calculated at 56 days on test were compared to end of test RFIs and were found to be significantly (P\u3c.0001) correlated at .85. RFI was found to be significantly (P\u3c.0001) correlated to average daily feed intake at .61, but not correlated to any other measures of performance including ultrasound traits